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ExprNode.cc

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  • ExprNode.cc 291.73 KiB
    /*
     * Copyright © 2007-2021 Dynare Team
     *
     * This file is part of Dynare.
     *
     * Dynare is free software: you can redistribute it and/or modify
     * it under the terms of the GNU General Public License as published by
     * the Free Software Foundation, either version 3 of the License, or
     * (at your option) any later version.
     *
     * Dynare is distributed in the hope that it will be useful,
     * but WITHOUT ANY WARRANTY; without even the implied warranty of
     * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
     * GNU General Public License for more details.
     *
     * You should have received a copy of the GNU General Public License
     * along with Dynare.  If not, see <https://www.gnu.org/licenses/>.
     */
    
    #include <iostream>
    #include <algorithm>
    #include <cassert>
    #include <cmath>
    #include <utility>
    #include <limits>
    
    #include "ExprNode.hh"
    #include "DataTree.hh"
    #include "ModFile.hh"
    
    ExprNode::ExprNode(DataTree &datatree_arg, int idx_arg) : datatree{datatree_arg}, idx{idx_arg}
    {
    }
    
    expr_t
    ExprNode::getDerivative(int deriv_id)
    {
      if (!preparedForDerivation)
        prepareForDerivation();
    
      // Return zero if derivative is necessarily null (using symbolic a priori)
      if (auto it = non_null_derivatives.find(deriv_id); it == non_null_derivatives.end())
        return datatree.Zero;
    
      // If derivative is stored in cache, use the cached value, otherwise compute it (and cache it)
      if (auto it2 = derivatives.find(deriv_id); it2 != derivatives.end())
        return it2->second;
      else
        {
          expr_t d = computeDerivative(deriv_id);
          derivatives[deriv_id] = d;
          return d;
        }
    }
    
    int
    ExprNode::precedence(ExprNodeOutputType output_type, const temporary_terms_t &temporary_terms) const
    {
      // For a constant, a variable, or a unary op, the precedence is maximal
      return 100;
    }
    
    int
    ExprNode::precedenceJson(const temporary_terms_t &temporary_terms) const
    {
      // For a constant, a variable, or a unary op, the precedence is maximal
      return 100;
    }
    
    int
    ExprNode::cost(int cost, bool is_matlab) const
    {
      // For a terminal node, the cost is null
      return 0;
    }
    
    int
    ExprNode::cost(const vector<vector<temporary_terms_t>> &blocks_temporary_terms, bool is_matlab) const
    {
      // For a terminal node, the cost is null
      return 0;
    }
    
    int
    ExprNode::cost(const map<pair<int, int>, temporary_terms_t> &temp_terms_map, bool is_matlab) const
    {
      // For a terminal node, the cost is null
      return 0;
    }
    
    bool
    ExprNode::checkIfTemporaryTermThenWrite(ostream &output, ExprNodeOutputType output_type,
                                            const temporary_terms_t &temporary_terms,
                                            const temporary_terms_idxs_t &temporary_terms_idxs) const
    {
      if (auto it = temporary_terms.find(const_cast<ExprNode *>(this)); it == temporary_terms.end())
        return false;
    
      auto it2 = temporary_terms_idxs.find(const_cast<ExprNode *>(this));
      // It is the responsibility of the caller to ensure that all temporary terms have their index
      assert(it2 != temporary_terms_idxs.end());
      output << "T" << LEFT_ARRAY_SUBSCRIPT(output_type)
             << it2->second + ARRAY_SUBSCRIPT_OFFSET(output_type)
             << RIGHT_ARRAY_SUBSCRIPT(output_type);
    
      return true;
    }
    
    pair<expr_t, int>
    ExprNode::getLagEquivalenceClass() const
    {
      int index = maxLead();
    
      if (index == numeric_limits<int>::min())
        index = 0; // If no variable in the expression, the equivalence class has size 1
    
      return { decreaseLeadsLags(index), index };
    }
    
    void
    ExprNode::collectVariables(SymbolType type, set<int> &result) const
    {
      set<pair<int, int>> symbs_lags;
      collectDynamicVariables(type, symbs_lags);
      transform(symbs_lags.begin(), symbs_lags.end(), inserter(result, result.begin()),
                [](auto x) { return x.first; });
    }
    
    void
    ExprNode::collectEndogenous(set<pair<int, int>> &result) const
    {
      set<pair<int, int>> symb_ids_and_lags;
      collectDynamicVariables(SymbolType::endogenous, symb_ids_and_lags);
      for (const auto &[symb_id, lag] : symb_ids_and_lags)
        result.emplace(datatree.symbol_table.getTypeSpecificID(symb_id), lag);
    }
    
    void
    ExprNode::computeTemporaryTerms(const pair<int, int> &derivOrder,
                                    map<pair<int, int>, temporary_terms_t> &temp_terms_map,
                                    map<expr_t, pair<int, pair<int, int>>> &reference_count,
                                    bool is_matlab) const
    {
      // Nothing to do for a terminal node
    }
    
    void
    ExprNode::computeBlockTemporaryTerms(int blk, int eq, vector<vector<temporary_terms_t>> &blocks_temporary_terms,
                                         map<expr_t, tuple<int, int, int>> &reference_count) const
    {
      // Nothing to do for a terminal node
    }
    
    void
    ExprNode::writeOutput(ostream &output) const
    {
      writeOutput(output, ExprNodeOutputType::matlabOutsideModel, {}, {});
    }
    
    void
    ExprNode::writeOutput(ostream &output, ExprNodeOutputType output_type) const
    {
      writeOutput(output, output_type, {}, {});
    }
    
    void
    ExprNode::writeOutput(ostream &output, ExprNodeOutputType output_type, const temporary_terms_t &temporary_terms, const temporary_terms_idxs_t &temporary_terms_idxs) const
    {
      writeOutput(output, output_type, temporary_terms, temporary_terms_idxs, {});
    }
    
    void
    ExprNode::compile(ostream &CompileCode, unsigned int &instruction_number,
                      bool lhs_rhs, const temporary_terms_t &temporary_terms,
                      const temporary_terms_idxs_t &temporary_terms_idxs, bool dynamic, bool steady_dynamic) const
    {
      compile(CompileCode, instruction_number, lhs_rhs, temporary_terms, temporary_terms_idxs, dynamic, steady_dynamic, {});
    }
    
    void
    ExprNode::writeExternalFunctionOutput(ostream &output, ExprNodeOutputType output_type,
                                          const temporary_terms_t &temporary_terms,
                                          const temporary_terms_idxs_t &temporary_terms_idxs,
                                          deriv_node_temp_terms_t &tef_terms) const
    {
      // Nothing to do
    }
    
    void
    ExprNode::writeJsonExternalFunctionOutput(vector<string> &efout,
                                              const temporary_terms_t &temporary_terms,
                                              deriv_node_temp_terms_t &tef_terms,
                                              bool isdynamic) const
    {
      // Nothing to do
    }
    
    void
    ExprNode::compileExternalFunctionOutput(ostream &CompileCode, unsigned int &instruction_number,
                                            bool lhs_rhs, const temporary_terms_t &temporary_terms,
                                            const temporary_terms_idxs_t &temporary_terms_idxs, bool dynamic, bool steady_dynamic,
                                            deriv_node_temp_terms_t &tef_terms) const
    {
      // Nothing to do
    }
    
    VariableNode *
    ExprNode::createEndoLeadAuxiliaryVarForMyself(subst_table_t &subst_table, vector<BinaryOpNode *> &neweqs) const
    {
      int n = maxEndoLead();
      assert(n >= 2);
    
      if (auto it = subst_table.find(this);
          it != subst_table.end())
        return const_cast<VariableNode *>(it->second);
    
      expr_t substexpr = decreaseLeadsLags(n-1);
      int lag = n-2;
    
      // Each iteration tries to create an auxvar such that auxvar(+1)=expr(-lag)
      // At the beginning (resp. end) of each iteration, substexpr is an expression (possibly an auxvar) equivalent to expr(-lag-1) (resp. expr(-lag))
      while (lag >= 0)
        {
          expr_t orig_expr = decreaseLeadsLags(lag);
          if (auto it = subst_table.find(orig_expr); it == subst_table.end())
            {
              int symb_id = datatree.symbol_table.addEndoLeadAuxiliaryVar(orig_expr->idx, substexpr);
              neweqs.push_back(datatree.AddEqual(datatree.AddVariable(symb_id, 0), substexpr));
              substexpr = datatree.AddVariable(symb_id, +1);
              assert(dynamic_cast<VariableNode *>(substexpr));
              subst_table[orig_expr] = dynamic_cast<VariableNode *>(substexpr);
            }
          else
            substexpr = const_cast<VariableNode *>(it->second);
    
          lag--;
        }
    
      return dynamic_cast<VariableNode *>(substexpr);
    }
    
    VariableNode *
    ExprNode::createExoLeadAuxiliaryVarForMyself(subst_table_t &subst_table, vector<BinaryOpNode *> &neweqs) const
    {
      int n = maxExoLead();
      assert(n >= 1);
    
      if (auto it = subst_table.find(this);
          it != subst_table.end())
        return const_cast<VariableNode *>(it->second);
    
      expr_t substexpr = decreaseLeadsLags(n);
      int lag = n-1;
    
      // Each iteration tries to create an auxvar such that auxvar(+1)=expr(-lag)
      // At the beginning (resp. end) of each iteration, substexpr is an expression (possibly an auxvar) equivalent to expr(-lag-1) (resp. expr(-lag))
      while (lag >= 0)
        {
          expr_t orig_expr = decreaseLeadsLags(lag);
          if (auto it = subst_table.find(orig_expr); it == subst_table.end())
            {
              int symb_id = datatree.symbol_table.addExoLeadAuxiliaryVar(orig_expr->idx, substexpr);
              neweqs.push_back(datatree.AddEqual(datatree.AddVariable(symb_id, 0), substexpr));
              substexpr = datatree.AddVariable(symb_id, +1);
              assert(dynamic_cast<VariableNode *>(substexpr));
              subst_table[orig_expr] = dynamic_cast<VariableNode *>(substexpr);
            }
          else
            substexpr = const_cast<VariableNode *>(it->second);
    
          lag--;
        }
    
      return dynamic_cast<VariableNode *>(substexpr);
    }
    
    bool
    ExprNode::isNumConstNodeEqualTo(double value) const
    {
      return false;
    }
    
    bool
    ExprNode::isVariableNodeEqualTo(SymbolType type_arg, int variable_id, int lag_arg) const
    {
      return false;
    }
    
    void
    ExprNode::fillErrorCorrectionRow(int eqn,
                                     const vector<int> &nontarget_lhs,
                                     const vector<int> &target_lhs,
                                     map<tuple<int, int, int>, expr_t> &A0,
                                     map<tuple<int, int, int>, expr_t> &A0star) const
    {
      vector<pair<expr_t, int>> terms;
      decomposeAdditiveTerms(terms, 1);
    
      for (const auto &it : terms)
        {
          pair<int, vector<tuple<int, int, int, double>>> m;
          try
            {
              m = it.first->matchParamTimesLinearCombinationOfVariables();
              for (auto &t : m.second)
                get<3>(t) *= it.second; // Update sign of constants
            }
          catch (MatchFailureException &e)
            {
              /* FIXME: we should not just skip them, but rather verify that they are
                 autoregressive terms or residuals (probably by merging the two "fill" procedures) */
              continue;
            }
    
          // Helper function
          auto one_step_orig = [this](int symb_id) {
                                 return datatree.symbol_table.isAuxiliaryVariable(symb_id) ?
                                   datatree.symbol_table.getOrigSymbIdForDiffAuxVar(symb_id) : symb_id;
                               };
    
          /* Verify that all variables belong to the error-correction term.
             FIXME: same remark as above about skipping terms. */
          bool not_ec = false;
          for (const auto &t : m.second)
            {
              int vid = one_step_orig(get<0>(t));
              not_ec = not_ec || (find(target_lhs.begin(), target_lhs.end(), vid) == target_lhs.end()
                                  && find(nontarget_lhs.begin(), nontarget_lhs.end(), vid) == nontarget_lhs.end());
            }
          if (not_ec)
            continue;
    
          // Now fill the matrices
          for (auto [var_id, lag, param_id, constant] : m.second)
            {
              int orig_vid = one_step_orig(var_id);
              int orig_lag = datatree.symbol_table.isAuxiliaryVariable(var_id) ? -datatree.symbol_table.getOrigLeadLagForDiffAuxVar(var_id) : lag;
              if (find(target_lhs.begin(), target_lhs.end(), orig_vid) == target_lhs.end())
                {
                  // This an LHS variable, so fill A0
                  if (constant != 1)
                    {
                      cerr << "ERROR in trend component model: LHS variable should not appear with a multiplicative constant in error correction term" << endl;
                      exit(EXIT_FAILURE);
                    }
                  if (param_id != -1)
                    {
                      cerr << "ERROR in trend component model: spurious parameter in error correction term" << endl;
                      exit(EXIT_FAILURE);
                    }
                  int colidx = static_cast<int>(distance(nontarget_lhs.begin(), find(nontarget_lhs.begin(), nontarget_lhs.end(), orig_vid)));
                  if (A0.find({eqn, -orig_lag, colidx}) != A0.end())
                    {
                      cerr << "ExprNode::fillErrorCorrection: Error filling A0 matrix: "
                           << "lag/symb_id encountered more than once in equation" << endl;
                      exit(EXIT_FAILURE);
                    }
                  A0[{eqn, -orig_lag, colidx}] = datatree.AddVariable(m.first);
                }
              else
                {
                  // This is a target, so fill A0star
                  int colidx = static_cast<int>(distance(target_lhs.begin(), find(target_lhs.begin(), target_lhs.end(), orig_vid)));
                  expr_t e = datatree.AddTimes(datatree.AddVariable(m.first), datatree.AddPossiblyNegativeConstant(-constant));
                  if (param_id != -1)
                    e = datatree.AddTimes(e, datatree.AddVariable(param_id));
                  if (auto coor = tuple(eqn, -orig_lag, colidx); A0star.find(coor) == A0star.end())
                    A0star[coor] = e;
                  else
                    A0star[coor] = datatree.AddPlus(e, A0star[coor]);
                }
            }
        }
    }
    
    void
    ExprNode::matchMatchedMoment(vector<int> &symb_ids, vector<int> &lags, vector<int> &powers) const
    {
      throw MatchFailureException{"Unsupported expression"};
    }
    
    bool
    ExprNode::isConstant() const
    {
      set<pair<int, int>> symbs_lags;
      collectDynamicVariables(SymbolType::endogenous, symbs_lags);
      collectDynamicVariables(SymbolType::exogenous, symbs_lags);
      collectDynamicVariables(SymbolType::exogenousDet, symbs_lags);
      return symbs_lags.empty();
    }
    
    bool
    ExprNode::hasExogenous() const
    {
      set<pair<int, int>> symbs_lags;
      collectDynamicVariables(SymbolType::exogenous, symbs_lags);
      collectDynamicVariables(SymbolType::exogenousDet, symbs_lags);
      return !symbs_lags.empty();
    }
    
    
    NumConstNode::NumConstNode(DataTree &datatree_arg, int idx_arg, int id_arg) :
      ExprNode{datatree_arg, idx_arg},
      id{id_arg}
    {
    }
    
    int
    NumConstNode::countDiffs() const
    {
      return 0;
    }
    
    void
    NumConstNode::prepareForDerivation()
    {
      preparedForDerivation = true;
      // All derivatives are null, so non_null_derivatives is left empty
    }
    
    expr_t
    NumConstNode::computeDerivative(int deriv_id)
    {
      return datatree.Zero;
    }
    
    void
    NumConstNode::writeOutput(ostream &output, ExprNodeOutputType output_type,
                              const temporary_terms_t &temporary_terms,
                              const temporary_terms_idxs_t &temporary_terms_idxs,
                              const deriv_node_temp_terms_t &tef_terms) const
    {
      if (!checkIfTemporaryTermThenWrite(output, output_type, temporary_terms, temporary_terms_idxs))
        output << datatree.num_constants.get(id);
    }
    
    void
    NumConstNode::writeJsonAST(ostream &output) const
    {
      output << R"({"node_type" : "NumConstNode", "value" : )";
      output << std::stof(datatree.num_constants.get(id)) << "}";
    }
    
    void
    NumConstNode::writeJsonOutput(ostream &output,
                                  const temporary_terms_t &temporary_terms,
                                  const deriv_node_temp_terms_t &tef_terms,
                                  bool isdynamic) const
    {
      output << datatree.num_constants.get(id);
    }
    
    bool
    NumConstNode::containsExternalFunction() const
    {
      return false;
    }
    
    double
    NumConstNode::eval(const eval_context_t &eval_context) const noexcept(false)
    {
      return datatree.num_constants.getDouble(id);
    }
    
    void
    NumConstNode::compile(ostream &CompileCode, unsigned int &instruction_number,
                          bool lhs_rhs, const temporary_terms_t &temporary_terms,
                          const temporary_terms_idxs_t &temporary_terms_idxs, bool dynamic, bool steady_dynamic,
                          const deriv_node_temp_terms_t &tef_terms) const
    {
      FLDC_ fldc(datatree.num_constants.getDouble(id));
      fldc.write(CompileCode, instruction_number);
    }
    
    void
    NumConstNode::collectVARLHSVariable(set<expr_t> &result) const
    {
      cerr << "ERROR: you can only have variables or unary ops on LHS of VAR" << endl;
      exit(EXIT_FAILURE);
    }
    
    void
    NumConstNode::collectDynamicVariables(SymbolType type_arg, set<pair<int, int>> &result) const
    {
    }
    
    void
    NumConstNode::computeSubExprContainingVariable(int symb_id, int lag, set<expr_t> &contain_var) const
    {
    }
    
    BinaryOpNode *
    NumConstNode::normalizeEquationHelper(const set<expr_t> &contain_var, expr_t rhs) const
    {
      cerr << "NumConstNode::normalizeEquation: this should not happen" << endl;
      exit(EXIT_FAILURE);
    }
    
    expr_t
    NumConstNode::getChainRuleDerivative(int deriv_id, const map<int, BinaryOpNode *> &recursive_variables)
    {
      return datatree.Zero;
    }
    
    expr_t
    NumConstNode::toStatic(DataTree &static_datatree) const
    {
      return static_datatree.AddNonNegativeConstant(datatree.num_constants.get(id));
    }
    
    void
    NumConstNode::computeXrefs(EquationInfo &ei) const
    {
    }
    
    expr_t
    NumConstNode::clone(DataTree &datatree) const
    {
      return datatree.AddNonNegativeConstant(datatree.num_constants.get(id));
    }
    
    int
    NumConstNode::maxEndoLead() const
    {
      return 0;
    }
    
    int
    NumConstNode::maxExoLead() const
    {
      return 0;
    }
    
    int
    NumConstNode::maxEndoLag() const
    {
      return 0;
    }
    
    int
    NumConstNode::maxExoLag() const
    {
      return 0;
    }
    
    int
    NumConstNode::maxLead() const
    {
      return numeric_limits<int>::min();
    }
    
    int
    NumConstNode::maxLag() const
    {
      return numeric_limits<int>::min();
    }
    
    int
    NumConstNode::maxLagWithDiffsExpanded() const
    {
      return numeric_limits<int>::min();
    }
    
    expr_t
    NumConstNode::undiff() const
    {
      return const_cast<NumConstNode *>(this);
    }
    
    int
    NumConstNode::VarMaxLag(const set<expr_t> &lhs_lag_equiv) const
    {
      return 0;
    }
    
    expr_t
    NumConstNode::decreaseLeadsLags(int n) const
    {
      return const_cast<NumConstNode *>(this);
    }
    
    expr_t
    NumConstNode::decreaseLeadsLagsPredeterminedVariables() const
    {
      return const_cast<NumConstNode *>(this);
    }
    
    expr_t
    NumConstNode::substituteEndoLeadGreaterThanTwo(subst_table_t &subst_table, vector<BinaryOpNode *> &neweqs, bool deterministic_model) const
    {
      return const_cast<NumConstNode *>(this);
    }
    
    expr_t
    NumConstNode::substituteEndoLagGreaterThanTwo(subst_table_t &subst_table, vector<BinaryOpNode *> &neweqs) const
    {
      return const_cast<NumConstNode *>(this);
    }
    
    expr_t
    NumConstNode::substituteExoLead(subst_table_t &subst_table, vector<BinaryOpNode *> &neweqs, bool deterministic_model) const
    {
      return const_cast<NumConstNode *>(this);
    }
    
    expr_t
    NumConstNode::substituteExoLag(subst_table_t &subst_table, vector<BinaryOpNode *> &neweqs) const
    {
      return const_cast<NumConstNode *>(this);
    }
    
    expr_t
    NumConstNode::substituteExpectation(subst_table_t &subst_table, vector<BinaryOpNode *> &neweqs, bool partial_information_model) const
    {
      return const_cast<NumConstNode *>(this);
    }
    
    expr_t
    NumConstNode::substituteAdl() const
    {
      return const_cast<NumConstNode *>(this);
    }
    
    expr_t
    NumConstNode::substituteModelLocalVariables() const
    {
      return const_cast<NumConstNode *>(this);
    }
    
    expr_t
    NumConstNode::substituteVarExpectation(const map<string, expr_t> &subst_table) const
    {
      return const_cast<NumConstNode *>(this);
    }
    
    void
    NumConstNode::findDiffNodes(lag_equivalence_table_t &nodes) const
    {
    }
    
    void
    NumConstNode::findUnaryOpNodesForAuxVarCreation(lag_equivalence_table_t &nodes) const
    {
    }
    
    int
    NumConstNode::findTargetVariable(int lhs_symb_id) const
    {
      return -1;
    }
    
    expr_t
    NumConstNode::substituteDiff(const lag_equivalence_table_t &nodes, subst_table_t &subst_table, vector<BinaryOpNode *> &neweqs) const
    {
      return const_cast<NumConstNode *>(this);
    }
    
    expr_t
    NumConstNode::substituteUnaryOpNodes(const lag_equivalence_table_t &nodes, subst_table_t &subst_table, vector<BinaryOpNode *> &neweqs) const
    {
      return const_cast<NumConstNode *>(this);
    }
    
    expr_t
    NumConstNode::substitutePacExpectation(const string &name, expr_t subexpr)
    {
      return const_cast<NumConstNode *>(this);
    }
    
    expr_t
    NumConstNode::substitutePacTargetNonstationary(const string &name, expr_t subexpr)
    {
      return const_cast<NumConstNode *>(this);
    }
    
    expr_t
    NumConstNode::differentiateForwardVars(const vector<string> &subset, subst_table_t &subst_table, vector<BinaryOpNode *> &neweqs) const
    {
      return const_cast<NumConstNode *>(this);
    }
    
    bool
    NumConstNode::isNumConstNodeEqualTo(double value) const
    {
      if (datatree.num_constants.getDouble(id) == value)
        return true;
      else
        return false;
    }
    
    bool
    NumConstNode::isVariableNodeEqualTo(SymbolType type_arg, int variable_id, int lag_arg) const
    {
      return false;
    }
    
    bool
    NumConstNode::containsPacExpectation(const string &pac_model_name) const
    {
      return false;
    }
    
    bool
    NumConstNode::containsPacTargetNonstationary(const string &pac_model_name) const
    {
      return false;
    }
    
    expr_t
    NumConstNode::replaceTrendVar() const
    {
      return const_cast<NumConstNode *>(this);
    }
    
    expr_t
    NumConstNode::detrend(int symb_id, bool log_trend, expr_t trend) const
    {
      return const_cast<NumConstNode *>(this);
    }
    
    expr_t
    NumConstNode::removeTrendLeadLag(const map<int, expr_t> &trend_symbols_map) const
    {
      return const_cast<NumConstNode *>(this);
    }
    
    bool
    NumConstNode::isInStaticForm() const
    {
      return true;
    }
    
    bool
    NumConstNode::isParamTimesEndogExpr() const
    {
      return false;
    }
    
    expr_t
    NumConstNode::substituteStaticAuxiliaryVariable() const
    {
      return const_cast<NumConstNode *>(this);
    }
    
    expr_t
    NumConstNode::replaceVarsInEquation(map<VariableNode *, NumConstNode *> &table) const
    {
      return const_cast<NumConstNode *>(this);
    }
    
    VariableNode::VariableNode(DataTree &datatree_arg, int idx_arg, int symb_id_arg, int lag_arg) :
      ExprNode{datatree_arg, idx_arg},
      symb_id{symb_id_arg},
      lag{lag_arg}
    {
      // It makes sense to allow a lead/lag on parameters: during steady state calibration, endogenous and parameters can be swapped
      assert(get_type() != SymbolType::externalFunction
             && (lag == 0 || (get_type() != SymbolType::modelLocalVariable && get_type() != SymbolType::modFileLocalVariable)));
    }
    
    void
    VariableNode::prepareForDerivation()
    {
      if (preparedForDerivation)
        return;
    
      preparedForDerivation = true;
    
      // Fill in non_null_derivatives
      switch (get_type())
        {
        case SymbolType::endogenous:
        case SymbolType::exogenous:
        case SymbolType::exogenousDet:
        case SymbolType::parameter:
        case SymbolType::trend:
        case SymbolType::logTrend:
          // For a variable or a parameter, the only non-null derivative is with respect to itself
          non_null_derivatives.insert(datatree.getDerivID(symb_id, lag));
          break;
        case SymbolType::modelLocalVariable:
          datatree.getLocalVariable(symb_id)->prepareForDerivation();
          // Non null derivatives are those of the value of the local parameter
          non_null_derivatives = datatree.getLocalVariable(symb_id)->non_null_derivatives;
          break;
        case SymbolType::modFileLocalVariable:
        case SymbolType::statementDeclaredVariable:
        case SymbolType::unusedEndogenous:
          // Such a variable is never derived
          break;
        case SymbolType::externalFunction:
        case SymbolType::epilogue:
          cerr << "VariableNode::prepareForDerivation: impossible case" << endl;
          exit(EXIT_FAILURE);
        case SymbolType::excludedVariable:
          cerr << "VariableNode::prepareForDerivation: impossible case: "
               << "You are trying to derive a variable that has been excluded via model_remove/var_remove/include_eqs/exclude_eqs: "
               << datatree.symbol_table.getName(symb_id) << endl;
          exit(EXIT_FAILURE);
        }
    }
    
    expr_t
    VariableNode::computeDerivative(int deriv_id)
    {
      switch (get_type())
        {
        case SymbolType::endogenous:
        case SymbolType::exogenous:
        case SymbolType::exogenousDet:
        case SymbolType::parameter:
        case SymbolType::trend:
        case SymbolType::logTrend:
          if (deriv_id == datatree.getDerivID(symb_id, lag))
            return datatree.One;
          else
            return datatree.Zero;
        case SymbolType::modelLocalVariable:
          return datatree.getLocalVariable(symb_id)->getDerivative(deriv_id);
        case SymbolType::modFileLocalVariable:
          cerr << "modFileLocalVariable is not derivable" << endl;
          exit(EXIT_FAILURE);
        case SymbolType::statementDeclaredVariable:
          cerr << "statementDeclaredVariable is not derivable" << endl;
          exit(EXIT_FAILURE);
        case SymbolType::unusedEndogenous:
          cerr << "unusedEndogenous is not derivable" << endl;
          exit(EXIT_FAILURE);
        case SymbolType::externalFunction:
        case SymbolType::epilogue:
        case SymbolType::excludedVariable:
          cerr << "VariableNode::computeDerivative: Impossible case!" << endl;
          exit(EXIT_FAILURE);
        }
      // Suppress GCC warning
      exit(EXIT_FAILURE);
    }
    
    bool
    VariableNode::containsExternalFunction() const
    {
      if (get_type() == SymbolType::modelLocalVariable)
        return datatree.getLocalVariable(symb_id)->containsExternalFunction();
    
      return false;
    }
    
    void
    VariableNode::writeJsonAST(ostream &output) const
    {
      output << R"({"node_type" : "VariableNode", )"
             << R"("name" : ")" << datatree.symbol_table.getName(symb_id) << R"(", "type" : ")";
      switch (get_type())
        {
        case SymbolType::endogenous:
          output << "endogenous";
          break;
        case SymbolType::exogenous:
          output << "exogenous";
          break;
        case SymbolType::exogenousDet:
          output << "exogenousDet";
          break;
        case SymbolType::parameter:
          output << "parameter";
          break;
        case SymbolType::modelLocalVariable:
          output << "modelLocalVariable";
          break;
        case SymbolType::modFileLocalVariable:
          output << "modFileLocalVariable";
          break;
        case SymbolType::externalFunction:
          output << "externalFunction";
          break;
        case SymbolType::trend:
          output << "trend";
          break;
        case SymbolType::statementDeclaredVariable:
          output << "statementDeclaredVariable";
          break;
        case SymbolType::logTrend:
          output << "logTrend:";
          break;
        case SymbolType::unusedEndogenous:
          output << "unusedEndogenous";
          break;
        case SymbolType::epilogue:
          output << "epilogue";
          break;
        case SymbolType::excludedVariable:
          cerr << "VariableNode::computeDerivative: Impossible case!" << endl;
          exit(EXIT_FAILURE);
        }
      output << R"(", "lag" : )" << lag << "}";
    }
    
    void
    VariableNode::writeJsonOutput(ostream &output,
                                  const temporary_terms_t &temporary_terms,
                                  const deriv_node_temp_terms_t &tef_terms,
                                  bool isdynamic) const
    {
      if (temporary_terms.find(const_cast<VariableNode *>(this)) != temporary_terms.end())
        {
          output << "T" << idx;
          return;
        }
    
      output << datatree.symbol_table.getName(symb_id);
      if (isdynamic && lag != 0)
        output << "(" << lag << ")";
    }
    
    void
    VariableNode::writeOutput(ostream &output, ExprNodeOutputType output_type,
                              const temporary_terms_t &temporary_terms,
                              const temporary_terms_idxs_t &temporary_terms_idxs,
                              const deriv_node_temp_terms_t &tef_terms) const
    {
      auto type = get_type();
      if (checkIfTemporaryTermThenWrite(output, output_type, temporary_terms, temporary_terms_idxs))
        return;
    
      if (isLatexOutput(output_type))
        {
          if (output_type == ExprNodeOutputType::latexDynamicSteadyStateOperator)
            output << R"(\bar)";
          output << "{" << datatree.symbol_table.getTeXName(symb_id) << "}";
          if (output_type == ExprNodeOutputType::latexDynamicModel
              && (type == SymbolType::endogenous || type == SymbolType::exogenous || type == SymbolType::exogenousDet || type == SymbolType::trend || type == SymbolType::logTrend))
            {
              output << "_{t";
              if (lag != 0)
                {
                  if (lag > 0)
                    output << "+";
                  output << lag;
                }
              output << "}";
            }
          return;
        }
    
      int i;
      switch (type)
        {
        case SymbolType::parameter:
          if (int tsid = datatree.symbol_table.getTypeSpecificID(symb_id);
              output_type == ExprNodeOutputType::matlabOutsideModel)
            output << "M_.params" << "(" << tsid + 1 << ")";
          else
            output << "params" << LEFT_ARRAY_SUBSCRIPT(output_type) << tsid + ARRAY_SUBSCRIPT_OFFSET(output_type) << RIGHT_ARRAY_SUBSCRIPT(output_type);
          break;
    
        case SymbolType::modelLocalVariable:
          if (output_type == ExprNodeOutputType::matlabDynamicSteadyStateOperator
              || output_type == ExprNodeOutputType::CDynamicSteadyStateOperator)
            {
              output << "(";
              datatree.getLocalVariable(symb_id)->writeOutput(output, output_type, temporary_terms, temporary_terms_idxs, tef_terms);
              output << ")";
            }
          else
            /* We append underscores to avoid name clashes with "g1" or "oo_".
               But we probably never arrive here because MLV are temporary terms… */
            output << datatree.symbol_table.getName(symb_id) << "__";
          break;
    
        case SymbolType::modFileLocalVariable:
          output << datatree.symbol_table.getName(symb_id);
          break;
    
        case SymbolType::endogenous:
          switch (int tsid = datatree.symbol_table.getTypeSpecificID(symb_id);
                  output_type)
            {
            case ExprNodeOutputType::juliaDynamicModel:
            case ExprNodeOutputType::matlabDynamicModel:
            case ExprNodeOutputType::CDynamicModel:
              i = datatree.getDynJacobianCol(datatree.getDerivID(symb_id, lag)) + ARRAY_SUBSCRIPT_OFFSET(output_type);
              output <<  "y" << LEFT_ARRAY_SUBSCRIPT(output_type) << i << RIGHT_ARRAY_SUBSCRIPT(output_type);
              break;
            case ExprNodeOutputType::CStaticModel:
            case ExprNodeOutputType::juliaStaticModel:
            case ExprNodeOutputType::matlabStaticModel:
              i = tsid + ARRAY_SUBSCRIPT_OFFSET(output_type);
              output <<  "y" << LEFT_ARRAY_SUBSCRIPT(output_type) << i << RIGHT_ARRAY_SUBSCRIPT(output_type);
              break;
            case ExprNodeOutputType::matlabOutsideModel:
              output << "oo_.steady_state(" << tsid + 1 << ")";
              break;
            case ExprNodeOutputType::juliaDynamicSteadyStateOperator:
            case ExprNodeOutputType::matlabDynamicSteadyStateOperator:
              output << "steady_state" << LEFT_ARRAY_SUBSCRIPT(output_type) << tsid + 1 << RIGHT_ARRAY_SUBSCRIPT(output_type);
              break;
            case ExprNodeOutputType::CDynamicSteadyStateOperator:
              output << "steady_state[" << tsid << "]";
              break;
            case ExprNodeOutputType::juliaSteadyStateFile:
            case ExprNodeOutputType::steadyStateFile:
              output << "ys_" << LEFT_ARRAY_SUBSCRIPT(output_type) << tsid + 1 << RIGHT_ARRAY_SUBSCRIPT(output_type);
              break;
            case ExprNodeOutputType::matlabDseries:
              output << "ds." << datatree.symbol_table.getName(symb_id);
              if (lag != 0)
                output << LEFT_ARRAY_SUBSCRIPT(output_type) << lag << RIGHT_ARRAY_SUBSCRIPT(output_type);
              break;
            case ExprNodeOutputType::epilogueFile:
              output << "ds." << datatree.symbol_table.getName(symb_id);
              output << LEFT_ARRAY_SUBSCRIPT(output_type) << "t";
              if (lag != 0)
                output << lag;
              output << RIGHT_ARRAY_SUBSCRIPT(output_type);
              break;
            case ExprNodeOutputType::occbinDifferenceFile:
              output << "zdatalinear(:," << tsid + 1 << ")";
              break;
            default:
              cerr << "VariableNode::writeOutput: should not reach this point" << endl;
              exit(EXIT_FAILURE);
            }
          break;
    
        case SymbolType::exogenous:
          i = datatree.symbol_table.getTypeSpecificID(symb_id) + ARRAY_SUBSCRIPT_OFFSET(output_type);
          switch (output_type)
            {
            case ExprNodeOutputType::juliaDynamicModel:
            case ExprNodeOutputType::matlabDynamicModel:
              if (lag > 0)
                output <<  "x" << LEFT_ARRAY_SUBSCRIPT(output_type) << "it_+" << lag << ", " << i
                       << RIGHT_ARRAY_SUBSCRIPT(output_type);
              else if (lag < 0)
                output <<  "x" << LEFT_ARRAY_SUBSCRIPT(output_type) << "it_" << lag << ", " << i
                       << RIGHT_ARRAY_SUBSCRIPT(output_type);
              else
                output <<  "x" << LEFT_ARRAY_SUBSCRIPT(output_type) << "it_, " << i
                       << RIGHT_ARRAY_SUBSCRIPT(output_type);
              break;
            case ExprNodeOutputType::CDynamicModel:
              if (lag == 0)
                output <<  "x[it_+" << i << "*nb_row_x]";
              else if (lag > 0)
                output <<  "x[it_+" << lag << "+" << i << "*nb_row_x]";
              else
                output <<  "x[it_" << lag << "+" << i << "*nb_row_x]";
              break;
            case ExprNodeOutputType::CStaticModel:
            case ExprNodeOutputType::juliaStaticModel:
            case ExprNodeOutputType::matlabStaticModel:
              output << "x" << LEFT_ARRAY_SUBSCRIPT(output_type) << i << RIGHT_ARRAY_SUBSCRIPT(output_type);
              break;
            case ExprNodeOutputType::matlabOutsideModel:
              assert(lag == 0);
              output <<  "oo_.exo_steady_state(" << i << ")";
              break;
            case ExprNodeOutputType::matlabDynamicSteadyStateOperator:
              output <<  "oo_.exo_steady_state(" << i << ")";
              break;
            case ExprNodeOutputType::juliaSteadyStateFile:
            case ExprNodeOutputType::steadyStateFile:
              output << "exo_" << LEFT_ARRAY_SUBSCRIPT(output_type) << i << RIGHT_ARRAY_SUBSCRIPT(output_type);
              break;
            case ExprNodeOutputType::matlabDseries:
              output << "ds." << datatree.symbol_table.getName(symb_id);
              if (lag != 0)
                output << LEFT_ARRAY_SUBSCRIPT(output_type) << lag << RIGHT_ARRAY_SUBSCRIPT(output_type);
              break;
            case ExprNodeOutputType::epilogueFile:
              output << "ds." << datatree.symbol_table.getName(symb_id);
              output << LEFT_ARRAY_SUBSCRIPT(output_type) << "t";
              if (lag != 0)
                output << lag;
              output << RIGHT_ARRAY_SUBSCRIPT(output_type);
              break;
            default:
              cerr << "VariableNode::writeOutput: should not reach this point" << endl;
              exit(EXIT_FAILURE);
            }
          break;
    
        case SymbolType::exogenousDet:
          i = datatree.symbol_table.getTypeSpecificID(symb_id) + datatree.symbol_table.exo_nbr() + ARRAY_SUBSCRIPT_OFFSET(output_type);
          switch (output_type)
            {
            case ExprNodeOutputType::juliaDynamicModel:
            case ExprNodeOutputType::matlabDynamicModel:
              if (lag > 0)
                output <<  "x" << LEFT_ARRAY_SUBSCRIPT(output_type) << "it_+" << lag << ", " << i
                       << RIGHT_ARRAY_SUBSCRIPT(output_type);
              else if (lag < 0)
                output <<  "x" << LEFT_ARRAY_SUBSCRIPT(output_type) << "it_" << lag << ", " << i
                       << RIGHT_ARRAY_SUBSCRIPT(output_type);
              else
                output <<  "x" << LEFT_ARRAY_SUBSCRIPT(output_type) << "it_, " << i
                       << RIGHT_ARRAY_SUBSCRIPT(output_type);
              break;
            case ExprNodeOutputType::CDynamicModel:
              if (lag == 0)
                output <<  "x[it_+" << i << "*nb_row_x]";
              else if (lag > 0)
                output <<  "x[it_+" << lag << "+" << i << "*nb_row_x]";
              else
                output <<  "x[it_" << lag << "+" << i << "*nb_row_x]";
              break;
            case ExprNodeOutputType::CStaticModel:
            case ExprNodeOutputType::juliaStaticModel:
            case ExprNodeOutputType::matlabStaticModel:
              output << "x" << LEFT_ARRAY_SUBSCRIPT(output_type) << i << RIGHT_ARRAY_SUBSCRIPT(output_type);
              break;
            case ExprNodeOutputType::matlabOutsideModel:
              assert(lag == 0);
              output <<  "oo_.exo_det_steady_state(" << datatree.symbol_table.getTypeSpecificID(symb_id) + 1 << ")";
              break;
            case ExprNodeOutputType::matlabDynamicSteadyStateOperator:
              output <<  "oo_.exo_det_steady_state(" << datatree.symbol_table.getTypeSpecificID(symb_id) + 1 << ")";
              break;
            case ExprNodeOutputType::juliaSteadyStateFile:
            case ExprNodeOutputType::steadyStateFile:
              output << "exo_" << LEFT_ARRAY_SUBSCRIPT(output_type) << i << RIGHT_ARRAY_SUBSCRIPT(output_type);
              break;
            case ExprNodeOutputType::matlabDseries:
              output << "ds." << datatree.symbol_table.getName(symb_id);
              if (lag != 0)
                output << LEFT_ARRAY_SUBSCRIPT(output_type) << lag << RIGHT_ARRAY_SUBSCRIPT(output_type);
              break;
            case ExprNodeOutputType::epilogueFile:
              output << "ds." << datatree.symbol_table.getName(symb_id);
              output << LEFT_ARRAY_SUBSCRIPT(output_type) << "t";
              if (lag != 0)
                output << lag;
              output << RIGHT_ARRAY_SUBSCRIPT(output_type);
              break;
            default:
              cerr << "VariableNode::writeOutput: should not reach this point" << endl;
              exit(EXIT_FAILURE);
            }
          break;
        case SymbolType::epilogue:
          if (output_type == ExprNodeOutputType::epilogueFile)
            {
              output << "ds." << datatree.symbol_table.getName(symb_id);
              output << LEFT_ARRAY_SUBSCRIPT(output_type) << "t";
              if (lag != 0)
                output << lag;
              output << RIGHT_ARRAY_SUBSCRIPT(output_type);
            }
          else if (output_type == ExprNodeOutputType::matlabDseries)
            // Only writing dseries for epilogue_static, hence no need to check lag
            output << "ds." << datatree.symbol_table.getName(symb_id);
          else
            {
              cerr << "VariableNode::writeOutput: Impossible case" << endl;
              exit(EXIT_FAILURE);
            }
          break;
        case SymbolType::unusedEndogenous:
          cerr << "ERROR: You cannot use an endogenous variable in an expression if that variable has not been used in the model block." << endl;
          exit(EXIT_FAILURE);
        case SymbolType::externalFunction:
        case SymbolType::trend:
        case SymbolType::logTrend:
        case SymbolType::statementDeclaredVariable:
        case SymbolType::excludedVariable:
          cerr << "VariableNode::writeOutput: Impossible case" << endl;
          exit(EXIT_FAILURE);
        }
    }
    
    expr_t
    VariableNode::substituteStaticAuxiliaryVariable() const
    {
      if (get_type() == SymbolType::endogenous)
        try
          {
            return datatree.symbol_table.getAuxiliaryVarsExprNode(symb_id)->substituteStaticAuxiliaryVariable();
          }
        catch (SymbolTable::SearchFailedException &e)
          {
          }
      return const_cast<VariableNode *>(this);
    }
    
    double
    VariableNode::eval(const eval_context_t &eval_context) const noexcept(false)
    {
      if (get_type() == SymbolType::modelLocalVariable)
        return datatree.getLocalVariable(symb_id)->eval(eval_context);
    
      auto it = eval_context.find(symb_id);
      if (it == eval_context.end())
        throw EvalException();
    
      return it->second;
    }
    
    void
    VariableNode::compile(ostream &CompileCode, unsigned int &instruction_number,
                          bool lhs_rhs, const temporary_terms_t &temporary_terms,
                          const temporary_terms_idxs_t &temporary_terms_idxs, bool dynamic, bool steady_dynamic,
                          const deriv_node_temp_terms_t &tef_terms) const
    {
      auto type = get_type();
      if (type == SymbolType::modelLocalVariable || type == SymbolType::modFileLocalVariable)
        datatree.getLocalVariable(symb_id)->compile(CompileCode, instruction_number, lhs_rhs, temporary_terms, temporary_terms_idxs, dynamic, steady_dynamic, tef_terms);
      else
        {
          int tsid = datatree.symbol_table.getTypeSpecificID(symb_id);
          if (type == SymbolType::exogenousDet)
            tsid += datatree.symbol_table.exo_nbr();
          if (!lhs_rhs)
            {
              if (dynamic)
                {
                  if (steady_dynamic) // steady state values in a dynamic model
                    {
                      FLDVS_ fldvs{static_cast<uint8_t>(type), static_cast<unsigned int>(tsid)};
                      fldvs.write(CompileCode, instruction_number);
                    }
                  else
                    {
                      if (type == SymbolType::parameter)
                        {
                          FLDV_ fldv{static_cast<int>(type), static_cast<unsigned int>(tsid)};
                          fldv.write(CompileCode, instruction_number);
                        }
                      else
                        {
                          FLDV_ fldv{static_cast<int>(type), static_cast<unsigned int>(tsid), lag};
                          fldv.write(CompileCode, instruction_number);
                        }
                    }
                }
              else
                {
                  FLDSV_ fldsv{static_cast<uint8_t>(type), static_cast<unsigned int>(tsid)};
                  fldsv.write(CompileCode, instruction_number);
                }
            }
          else
            {
              if (dynamic)
                {
                  if (steady_dynamic) // steady state values in a dynamic model
                    {
                      cerr << "Impossible case: steady_state in rhs of equation" << endl;
                      exit(EXIT_FAILURE);
                    }
                  else
                    {
                      if (type == SymbolType::parameter)
                        {
                          FSTPV_ fstpv{static_cast<int>(type), static_cast<unsigned int>(tsid)};
                          fstpv.write(CompileCode, instruction_number);
                        }
                      else
                        {
                          FSTPV_ fstpv{static_cast<int>(type), static_cast<unsigned int>(tsid), lag};
                          fstpv.write(CompileCode, instruction_number);
                        }
                    }
                }
              else
                {
                  FSTPSV_ fstpsv{static_cast<uint8_t>(type), static_cast<unsigned int>(tsid)};
                  fstpsv.write(CompileCode, instruction_number);
                }
            }
        }
    }
    
    void
    VariableNode::collectVARLHSVariable(set<expr_t> &result) const
    {
      if (get_type() == SymbolType::endogenous && lag == 0)
        result.insert(const_cast<VariableNode *>(this));
      else
        {
          cerr << "ERROR: you can only have endogenous variables or unary ops on LHS of VAR" << endl;
          exit(EXIT_FAILURE);
        }
    }
    
    void
    VariableNode::collectDynamicVariables(SymbolType type_arg, set<pair<int, int>> &result) const
    {
      if (get_type() == type_arg)
        result.emplace(symb_id, lag);
      if (get_type() == SymbolType::modelLocalVariable)
        datatree.getLocalVariable(symb_id)->collectDynamicVariables(type_arg, result);
    }
    
    void
    VariableNode::computeSubExprContainingVariable(int symb_id_arg, int lag_arg, set<expr_t> &contain_var) const
    {
      if (symb_id == symb_id_arg && lag == lag_arg)
        contain_var.insert(const_cast<VariableNode*>(this));
      if (get_type() == SymbolType::modelLocalVariable)
        datatree.getLocalVariable(symb_id)->computeSubExprContainingVariable(symb_id_arg, lag_arg, contain_var);
    }
    
    BinaryOpNode *
    VariableNode::normalizeEquationHelper(const set<expr_t> &contain_var, expr_t rhs) const
    {
      assert(contain_var.count(const_cast<VariableNode *>(this)) > 0);
    
      if (get_type() == SymbolType::modelLocalVariable)
        return datatree.getLocalVariable(symb_id)->normalizeEquationHelper(contain_var, rhs);
    
      // This the LHS variable: we have finished the normalization
      return datatree.AddEqual(const_cast<VariableNode *>(this), rhs);
    }
    
    expr_t
    VariableNode::getChainRuleDerivative(int deriv_id, const map<int, BinaryOpNode *> &recursive_variables)
    {
      switch (get_type())
        {
        case SymbolType::endogenous:
        case SymbolType::exogenous:
        case SymbolType::exogenousDet:
        case SymbolType::parameter:
        case SymbolType::trend:
        case SymbolType::logTrend:
          if (deriv_id == datatree.getDerivID(symb_id, lag))
            return datatree.One;
          // If there is in the equation a recursive variable we could use a chaine rule derivation
          else if (auto it = recursive_variables.find(datatree.getDerivID(symb_id, lag));
                   it != recursive_variables.end())
            return it->second->arg2->getChainRuleDerivative(deriv_id, recursive_variables);
          else
            return datatree.Zero;
    
        case SymbolType::modelLocalVariable:
          return datatree.getLocalVariable(symb_id)->getChainRuleDerivative(deriv_id, recursive_variables);
        case SymbolType::modFileLocalVariable:
          cerr << "modFileLocalVariable is not derivable" << endl;
          exit(EXIT_FAILURE);
        case SymbolType::statementDeclaredVariable:
          cerr << "statementDeclaredVariable is not derivable" << endl;
          exit(EXIT_FAILURE);
        case SymbolType::unusedEndogenous:
          cerr << "unusedEndogenous is not derivable" << endl;
          exit(EXIT_FAILURE);
        case SymbolType::externalFunction:
        case SymbolType::epilogue:
        case SymbolType::excludedVariable:
          cerr << "VariableNode::getChainRuleDerivative: Impossible case" << endl;
          exit(EXIT_FAILURE);
        }
      // Suppress GCC warning
      exit(EXIT_FAILURE);
    }
    
    expr_t
    VariableNode::toStatic(DataTree &static_datatree) const
    {
      return static_datatree.AddVariable(symb_id);
    }
    
    void
    VariableNode::computeXrefs(EquationInfo &ei) const
    {
      switch (get_type())
        {
        case SymbolType::endogenous:
          ei.endo.emplace(symb_id, lag);
          break;
        case SymbolType::exogenous:
          ei.exo.emplace(symb_id, lag);
          break;
        case SymbolType::exogenousDet:
          ei.exo_det.emplace(symb_id, lag);
          break;
        case SymbolType::parameter:
          ei.param.emplace(symb_id, 0);
          break;
        case SymbolType::modFileLocalVariable:
          datatree.getLocalVariable(symb_id)->computeXrefs(ei);
          break;
        case SymbolType::trend:
        case SymbolType::logTrend:
        case SymbolType::modelLocalVariable:
        case SymbolType::statementDeclaredVariable:
        case SymbolType::unusedEndogenous:
        case SymbolType::externalFunction:
        case SymbolType::epilogue:
        case SymbolType::excludedVariable:
          break;
        }
    }
    
    SymbolType
    VariableNode::get_type() const
    {
      return datatree.symbol_table.getType(symb_id);
    }
    
    expr_t
    VariableNode::clone(DataTree &datatree) const
    {
      return datatree.AddVariable(symb_id, lag);
    }
    
    int
    VariableNode::maxEndoLead() const
    {
      switch (get_type())
        {
        case SymbolType::endogenous:
          return max(lag, 0);
        case SymbolType::modelLocalVariable:
          return datatree.getLocalVariable(symb_id)->maxEndoLead();
        default:
          return 0;
        }
    }
    
    int
    VariableNode::maxExoLead() const
    {
      switch (get_type())
        {
        case SymbolType::exogenous:
          return max(lag, 0);
        case SymbolType::modelLocalVariable:
          return datatree.getLocalVariable(symb_id)->maxExoLead();
        default:
          return 0;
        }
    }
    
    int
    VariableNode::maxEndoLag() const
    {
      switch (get_type())
        {
        case SymbolType::endogenous:
          return max(-lag, 0);
        case SymbolType::modelLocalVariable:
          return datatree.getLocalVariable(symb_id)->maxEndoLag();
        default:
          return 0;
        }
    }
    
    int
    VariableNode::maxExoLag() const
    {
      switch (get_type())
        {
        case SymbolType::exogenous:
          return max(-lag, 0);
        case SymbolType::modelLocalVariable:
          return datatree.getLocalVariable(symb_id)->maxExoLag();
        default:
          return 0;
        }
    }
    
    int
    VariableNode::maxLead() const
    {
      switch (get_type())
        {
        case SymbolType::endogenous:
        case SymbolType::exogenous:
        case SymbolType::exogenousDet:
          return lag;
        case SymbolType::modelLocalVariable:
          return datatree.getLocalVariable(symb_id)->maxLead();
        default:
          return 0;
        }
    }
    
    int
    VariableNode::maxLag() const
    {
      switch (get_type())
        {
        case SymbolType::endogenous:
        case SymbolType::exogenous:
        case SymbolType::exogenousDet:
          return -lag;
        case SymbolType::modelLocalVariable:
          return datatree.getLocalVariable(symb_id)->maxLag();
        default:
          return 0;
        }
    }
    
    int
    VariableNode::maxLagWithDiffsExpanded() const
    {
      switch (get_type())
        {
        case SymbolType::endogenous:
        case SymbolType::exogenous:
        case SymbolType::exogenousDet:
        case SymbolType::epilogue:
          return -lag;
        case SymbolType::modelLocalVariable:
          return datatree.getLocalVariable(symb_id)->maxLagWithDiffsExpanded();
        default:
          return 0;
        }
    }
    
    expr_t
    VariableNode::undiff() const
    {
      return const_cast<VariableNode *>(this);
    }
    
    int
    VariableNode::VarMaxLag(const set<expr_t> &lhs_lag_equiv) const
    {
      auto [lag_equiv_repr, index] = getLagEquivalenceClass();
      if (lhs_lag_equiv.find(lag_equiv_repr) == lhs_lag_equiv.end())
        return 0;
      return maxLag();
    }
    
    expr_t
    VariableNode::substituteAdl() const
    {
      /* Do not recurse into model-local variables definition, rather do it at the
         DynamicModel method level (see the comment there) */
      return const_cast<VariableNode *>(this);
    }
    
    expr_t
    VariableNode::substituteModelLocalVariables() const
    {
      if (get_type() == SymbolType::modelLocalVariable)
        return datatree.getLocalVariable(symb_id);
    
      return const_cast<VariableNode *>(this);
    }
    
    expr_t
    VariableNode::substituteVarExpectation(const map<string, expr_t> &subst_table) const
    {
      if (get_type() == SymbolType::modelLocalVariable)
        return datatree.getLocalVariable(symb_id)->substituteVarExpectation(subst_table);
    
      return const_cast<VariableNode *>(this);
    }
    
    void
    VariableNode::findDiffNodes(lag_equivalence_table_t &nodes) const
    {
      if (get_type() == SymbolType::modelLocalVariable)
        datatree.getLocalVariable(symb_id)->findDiffNodes(nodes);
    }
    
    void
    VariableNode::findUnaryOpNodesForAuxVarCreation(lag_equivalence_table_t &nodes) const
    {
      if (get_type() == SymbolType::modelLocalVariable)
        datatree.getLocalVariable(symb_id)->findUnaryOpNodesForAuxVarCreation(nodes);
    }
    
    int
    VariableNode::findTargetVariable(int lhs_symb_id) const
    {
      if (get_type() == SymbolType::modelLocalVariable)
        return datatree.getLocalVariable(symb_id)->findTargetVariable(lhs_symb_id);
    
      return -1;
    }
    
    expr_t
    VariableNode::substituteDiff(const lag_equivalence_table_t &nodes, subst_table_t &subst_table,
                                 vector<BinaryOpNode *> &neweqs) const
    {
      if (get_type() == SymbolType::modelLocalVariable)
        return datatree.getLocalVariable(symb_id)->substituteDiff(nodes, subst_table, neweqs);
    
      return const_cast<VariableNode *>(this);
    }
    
    expr_t
    VariableNode::substituteUnaryOpNodes(const lag_equivalence_table_t &nodes, subst_table_t &subst_table, vector<BinaryOpNode *> &neweqs) const
    {
      if (get_type() == SymbolType::modelLocalVariable)
        return datatree.getLocalVariable(symb_id)->substituteUnaryOpNodes(nodes, subst_table, neweqs);
    
      return const_cast<VariableNode *>(this);
    }
    
    expr_t
    VariableNode::substitutePacExpectation(const string &name, expr_t subexpr)
    {
      if (get_type() == SymbolType::modelLocalVariable)
        return datatree.getLocalVariable(symb_id)->substitutePacExpectation(name, subexpr);
    
      return const_cast<VariableNode *>(this);
    }
    
    expr_t
    VariableNode::substitutePacTargetNonstationary(const string &name, expr_t subexpr)
    {
      if (get_type() == SymbolType::modelLocalVariable)
        return datatree.getLocalVariable(symb_id)->substitutePacTargetNonstationary(name, subexpr);
    
      return const_cast<VariableNode *>(this);
    }
    
    expr_t
    VariableNode::decreaseLeadsLags(int n) const
    {
      switch (get_type())
        {
        case SymbolType::endogenous:
        case SymbolType::exogenous:
        case SymbolType::exogenousDet:
        case SymbolType::trend:
        case SymbolType::logTrend:
          return datatree.AddVariable(symb_id, lag-n);
        case SymbolType::modelLocalVariable:
          return datatree.getLocalVariable(symb_id)->decreaseLeadsLags(n);
        default:
          return const_cast<VariableNode *>(this);
        }
    }
    
    expr_t
    VariableNode::decreaseLeadsLagsPredeterminedVariables() const
    {
      /* Do not recurse into model-local variables definitions, since MLVs are
         already handled by DynamicModel::transformPredeterminedVariables().
         This is also necessary because of #65. */
      if (datatree.symbol_table.isPredetermined(symb_id))
        return decreaseLeadsLags(1);
      else
        return const_cast<VariableNode *>(this);
    }
    
    expr_t
    VariableNode::substituteEndoLeadGreaterThanTwo(subst_table_t &subst_table, vector<BinaryOpNode *> &neweqs, bool deterministic_model) const
    {
      switch (get_type())
        {
        case SymbolType::endogenous:
          if (lag <= 1)
            return const_cast<VariableNode *>(this);
          else
            return createEndoLeadAuxiliaryVarForMyself(subst_table, neweqs);
        case SymbolType::modelLocalVariable:
          if (expr_t value = datatree.getLocalVariable(symb_id); value->maxEndoLead() <= 1)
            return const_cast<VariableNode *>(this);
          else
            return value->substituteEndoLeadGreaterThanTwo(subst_table, neweqs, deterministic_model);
        default:
          return const_cast<VariableNode *>(this);
        }
    }
    
    expr_t
    VariableNode::substituteEndoLagGreaterThanTwo(subst_table_t &subst_table, vector<BinaryOpNode *> &neweqs) const
    {
      VariableNode *substexpr;
      int cur_lag;
      switch (get_type())
        {
        case SymbolType::endogenous:
          if (lag >= -1)
            return const_cast<VariableNode *>(this);
    
          if (auto it = subst_table.find(this); it != subst_table.end())
            return const_cast<VariableNode *>(it->second);
    
          substexpr = datatree.AddVariable(symb_id, -1);
          cur_lag = -2;
    
          // Each iteration tries to create an auxvar such that auxvar(-1)=curvar(cur_lag)
          // At the beginning (resp. end) of each iteration, substexpr is an expression (possibly an auxvar) equivalent to curvar(cur_lag+1) (resp. curvar(cur_lag))
          while (cur_lag >= lag)
            {
              VariableNode *orig_expr = datatree.AddVariable(symb_id, cur_lag);
              if (auto it = subst_table.find(orig_expr); it == subst_table.end())
                {
                  int aux_symb_id = datatree.symbol_table.addEndoLagAuxiliaryVar(symb_id, cur_lag+1, substexpr);
                  neweqs.push_back(datatree.AddEqual(datatree.AddVariable(aux_symb_id, 0), substexpr));
                  substexpr = datatree.AddVariable(aux_symb_id, -1);
                  subst_table[orig_expr] = substexpr;
                }
              else
                substexpr = const_cast<VariableNode *>(it->second);
    
              cur_lag--;
            }
          return substexpr;
    
        case SymbolType::modelLocalVariable:
          if (expr_t value = datatree.getLocalVariable(symb_id); value->maxEndoLag() <= 1)
            return const_cast<VariableNode *>(this);
          else
            return value->substituteEndoLagGreaterThanTwo(subst_table, neweqs);
        default:
          return const_cast<VariableNode *>(this);
        }
    }
    
    expr_t
    VariableNode::substituteExoLead(subst_table_t &subst_table, vector<BinaryOpNode *> &neweqs, bool deterministic_model) const
    {
      switch (get_type())
        {
        case SymbolType::exogenous:
          if (lag <= 0)
            return const_cast<VariableNode *>(this);
          else
            return createExoLeadAuxiliaryVarForMyself(subst_table, neweqs);
        case SymbolType::modelLocalVariable:
          if (expr_t value = datatree.getLocalVariable(symb_id); value->maxExoLead() == 0)
            return const_cast<VariableNode *>(this);
          else
            return value->substituteExoLead(subst_table, neweqs, deterministic_model);
        default:
          return const_cast<VariableNode *>(this);
        }
    }
    
    expr_t
    VariableNode::substituteExoLag(subst_table_t &subst_table, vector<BinaryOpNode *> &neweqs) const
    {
      VariableNode *substexpr;
      int cur_lag;
      switch (get_type())
        {
        case SymbolType::exogenous:
          if (lag >= 0)
            return const_cast<VariableNode *>(this);
    
          if (auto it = subst_table.find(this); it != subst_table.end())
            return const_cast<VariableNode *>(it->second);
    
          substexpr = datatree.AddVariable(symb_id, 0);
          cur_lag = -1;
    
          // Each iteration tries to create an auxvar such that auxvar(-1)=curvar(cur_lag)
          // At the beginning (resp. end) of each iteration, substexpr is an expression (possibly an auxvar) equivalent to curvar(cur_lag+1) (resp. curvar(cur_lag))
          while (cur_lag >= lag)
            {
              VariableNode *orig_expr = datatree.AddVariable(symb_id, cur_lag);
              if (auto it = subst_table.find(orig_expr); it == subst_table.end())
                {
                  int aux_symb_id = datatree.symbol_table.addExoLagAuxiliaryVar(symb_id, cur_lag+1, substexpr);
                  neweqs.push_back(datatree.AddEqual(datatree.AddVariable(aux_symb_id, 0), substexpr));
                  substexpr = datatree.AddVariable(aux_symb_id, -1);
                  subst_table[orig_expr] = substexpr;
                }
              else
                substexpr = const_cast<VariableNode *>(it->second);
    
              cur_lag--;
            }
          return substexpr;
    
        case SymbolType::modelLocalVariable:
          if (expr_t value = datatree.getLocalVariable(symb_id); value->maxExoLag() == 0)
            return const_cast<VariableNode *>(this);
          else
            return value->substituteExoLag(subst_table, neweqs);
        default:
          return const_cast<VariableNode *>(this);
        }
    }
    
    expr_t
    VariableNode::substituteExpectation(subst_table_t &subst_table, vector<BinaryOpNode *> &neweqs, bool partial_information_model) const
    {
      if (get_type() == SymbolType::modelLocalVariable)
        return datatree.getLocalVariable(symb_id)->substituteExpectation(subst_table, neweqs, partial_information_model);
    
      return const_cast<VariableNode *>(this);
    }
    
    expr_t
    VariableNode::differentiateForwardVars(const vector<string> &subset, subst_table_t &subst_table, vector<BinaryOpNode *> &neweqs) const
    {
      switch (get_type())
        {
        case SymbolType::endogenous:
          assert(lag <= 1);
          if (lag <= 0
              || (subset.size() > 0
                  && find(subset.begin(), subset.end(), datatree.symbol_table.getName(symb_id)) == subset.end()))
            return const_cast<VariableNode *>(this);
          else
            {
              VariableNode *diffvar;
              if (auto it = subst_table.find(this); it != subst_table.end())
                diffvar = const_cast<VariableNode *>(it->second);
              else
                {
                  int aux_symb_id = datatree.symbol_table.addDiffForwardAuxiliaryVar(symb_id, datatree.AddMinus(datatree.AddVariable(symb_id, 0),
                                                                                                                datatree.AddVariable(symb_id, -1)));
                  neweqs.push_back(datatree.AddEqual(datatree.AddVariable(aux_symb_id, 0), datatree.AddMinus(datatree.AddVariable(symb_id, 0),
                                                                                                                                          datatree.AddVariable(symb_id, -1))));
                  diffvar = datatree.AddVariable(aux_symb_id, 1);
                  subst_table[this] = diffvar;
                }
              return datatree.AddPlus(datatree.AddVariable(symb_id, 0), diffvar);
            }
        case SymbolType::modelLocalVariable:
          if (expr_t value = datatree.getLocalVariable(symb_id); value->maxEndoLead() <= 0)
            return const_cast<VariableNode *>(this);
          else
            return value->differentiateForwardVars(subset, subst_table, neweqs);
        default:
          return const_cast<VariableNode *>(this);
        }
    }
    
    bool
    VariableNode::isNumConstNodeEqualTo(double value) const
    {
      return false;
    }
    
    bool
    VariableNode::isVariableNodeEqualTo(SymbolType type_arg, int variable_id, int lag_arg) const
    {
      if (get_type() == type_arg && datatree.symbol_table.getTypeSpecificID(symb_id) == variable_id && lag == lag_arg)
        return true;
      else
        return false;
    }
    
    bool
    VariableNode::containsPacExpectation(const string &pac_model_name) const
    {
      if (get_type() == SymbolType::modelLocalVariable)
        return datatree.getLocalVariable(symb_id)->containsPacExpectation(pac_model_name);
    
      return false;
    }
    
    bool
    VariableNode::containsPacTargetNonstationary(const string &pac_model_name) const
    {
      if (get_type() == SymbolType::modelLocalVariable)
        return datatree.getLocalVariable(symb_id)->containsPacTargetNonstationary(pac_model_name);
    
      return false;
    }
    
    expr_t
    VariableNode::replaceTrendVar() const
    {
      if (get_type() == SymbolType::modelLocalVariable)
        return datatree.getLocalVariable(symb_id)->replaceTrendVar();
    
      if (get_type() == SymbolType::trend)
        return datatree.One;
      else if (get_type() == SymbolType::logTrend)
        return datatree.Zero;
      else
        return const_cast<VariableNode *>(this);
    }
    
    expr_t
    VariableNode::detrend(int symb_id, bool log_trend, expr_t trend) const
    {
      if (get_type() == SymbolType::modelLocalVariable)
        return datatree.getLocalVariable(symb_id)->detrend(symb_id, log_trend, trend);
    
      if (this->symb_id != symb_id)
        return const_cast<VariableNode *>(this);
    
      if (log_trend)
        {
          if (lag == 0)
            return datatree.AddPlus(const_cast<VariableNode *>(this), trend);
          else
            return datatree.AddPlus(const_cast<VariableNode *>(this), trend->decreaseLeadsLags(-lag));
        }
      else
        {
          if (lag == 0)
            return datatree.AddTimes(const_cast<VariableNode *>(this), trend);
          else
            return datatree.AddTimes(const_cast<VariableNode *>(this), trend->decreaseLeadsLags(-lag));
        }
    }
    
    int
    VariableNode::countDiffs() const
    {
      if (get_type() == SymbolType::modelLocalVariable)
        return datatree.getLocalVariable(symb_id)->countDiffs();
    
      return 0;
    }
    
    expr_t
    VariableNode::removeTrendLeadLag(const map<int, expr_t> &trend_symbols_map) const
    {
      if (get_type() == SymbolType::modelLocalVariable)
        return datatree.getLocalVariable(symb_id)->removeTrendLeadLag(trend_symbols_map);
    
      if ((get_type() != SymbolType::trend && get_type() != SymbolType::logTrend) || lag == 0)
        return const_cast<VariableNode *>(this);
    
      auto it = trend_symbols_map.find(symb_id);
      expr_t noTrendLeadLagNode = datatree.AddVariable(it->first);
      bool log_trend = get_type() == SymbolType::logTrend;
      expr_t trend = it->second;
    
      if (lag > 0)
        {
          expr_t growthFactorSequence = trend->decreaseLeadsLags(-1);
          if (log_trend)
            {
              for (int i = 1; i < lag; i++)
                growthFactorSequence = datatree.AddPlus(growthFactorSequence, trend->decreaseLeadsLags(-1*(i+1)));
              return datatree.AddPlus(noTrendLeadLagNode, growthFactorSequence);
            }
          else
            {
              for (int i = 1; i < lag; i++)
                growthFactorSequence = datatree.AddTimes(growthFactorSequence, trend->decreaseLeadsLags(-1*(i+1)));
              return datatree.AddTimes(noTrendLeadLagNode, growthFactorSequence);
            }
        }
      else //get_lag < 0
        {
          expr_t growthFactorSequence = trend;
          if (log_trend)
            {
              for (int i = 1; i < abs(lag); i++)
                growthFactorSequence = datatree.AddPlus(growthFactorSequence, trend->decreaseLeadsLags(i));
              return datatree.AddMinus(noTrendLeadLagNode, growthFactorSequence);
            }
          else
            {
              for (int i = 1; i < abs(lag); i++)
                growthFactorSequence = datatree.AddTimes(growthFactorSequence, trend->decreaseLeadsLags(i));
              return datatree.AddDivide(noTrendLeadLagNode, growthFactorSequence);
            }
        }
    }
    
    bool
    VariableNode::isInStaticForm() const
    {
      if (get_type() == SymbolType::modelLocalVariable)
        return datatree.getLocalVariable(symb_id)->isInStaticForm();
    
      return lag == 0;
    }
    
    bool
    VariableNode::isParamTimesEndogExpr() const
    {
      if (get_type() == SymbolType::modelLocalVariable)
        return datatree.getLocalVariable(symb_id)->isParamTimesEndogExpr();
    
      return false;
    }
    
    expr_t
    VariableNode::replaceVarsInEquation(map<VariableNode *, NumConstNode *> &table) const
    {
      /* Do not recurse into model-local variables definitions, since MLVs are
         already handled by DynamicModel::simplifyEquations().
         This is also necessary because of #65. */
      for (auto &it : table)
        if (it.first->symb_id == symb_id)
          return it.second;
      return const_cast<VariableNode *>(this);
    }
    
    void
    VariableNode::matchMatchedMoment(vector<int> &symb_ids, vector<int> &lags, vector<int> &powers) const
    {
      /* Used for simple expression outside model block, so no need to special-case
         model local variables */
    
      if (get_type() != SymbolType::endogenous)
        throw MatchFailureException{"Variable " + datatree.symbol_table.getName(symb_id) + " is not an endogenous"};
    
      symb_ids.push_back(symb_id);
      lags.push_back(lag);
      powers.push_back(1);
    }
    
    UnaryOpNode::UnaryOpNode(DataTree &datatree_arg, int idx_arg, UnaryOpcode op_code_arg, const expr_t arg_arg, int expectation_information_set_arg, int param1_symb_id_arg, int param2_symb_id_arg, string adl_param_name_arg, vector<int> adl_lags_arg) :
      ExprNode{datatree_arg, idx_arg},
      arg{arg_arg},
      expectation_information_set{expectation_information_set_arg},
      param1_symb_id{param1_symb_id_arg},
      param2_symb_id{param2_symb_id_arg},
      op_code{op_code_arg},
      adl_param_name{move(adl_param_name_arg)},
      adl_lags{move(adl_lags_arg)}
    {
    }
    
    void
    UnaryOpNode::prepareForDerivation()
    {
      if (preparedForDerivation)
        return;
    
      preparedForDerivation = true;
    
      arg->prepareForDerivation();
    
      // Non-null derivatives are those of the argument (except for STEADY_STATE)
      non_null_derivatives = arg->non_null_derivatives;
      if (op_code == UnaryOpcode::steadyState || op_code == UnaryOpcode::steadyStateParamDeriv
          || op_code == UnaryOpcode::steadyStateParam2ndDeriv)
        datatree.addAllParamDerivId(non_null_derivatives);
    }
    
    expr_t
    UnaryOpNode::composeDerivatives(expr_t darg, int deriv_id)
    {
      expr_t t11, t12, t13, t14, t15;
    
      switch (op_code)
        {
        case UnaryOpcode::uminus:
          return datatree.AddUMinus(darg);
        case UnaryOpcode::exp:
          return datatree.AddTimes(darg, this);
        case UnaryOpcode::log:
          return datatree.AddDivide(darg, arg);
        case UnaryOpcode::log10:
          t11 = datatree.AddExp(datatree.One);
          t12 = datatree.AddLog10(t11);
          t13 = datatree.AddDivide(darg, arg);
          return datatree.AddTimes(t12, t13);
        case UnaryOpcode::cos:
          t11 = datatree.AddSin(arg);
          t12 = datatree.AddUMinus(t11);
          return datatree.AddTimes(darg, t12);
        case UnaryOpcode::sin:
          t11 = datatree.AddCos(arg);
          return datatree.AddTimes(darg, t11);
        case UnaryOpcode::tan:
          t11 = datatree.AddTimes(this, this);
          t12 = datatree.AddPlus(t11, datatree.One);
          return datatree.AddTimes(darg, t12);
        case UnaryOpcode::acos:
          t11 = datatree.AddSin(this);
          t12 = datatree.AddDivide(darg, t11);
          return datatree.AddUMinus(t12);
        case UnaryOpcode::asin:
          t11 = datatree.AddCos(this);
          return datatree.AddDivide(darg, t11);
        case UnaryOpcode::atan:
          t11 = datatree.AddTimes(arg, arg);
          t12 = datatree.AddPlus(datatree.One, t11);
          return datatree.AddDivide(darg, t12);
        case UnaryOpcode::cosh:
          t11 = datatree.AddSinh(arg);
          return datatree.AddTimes(darg, t11);
        case UnaryOpcode::sinh:
          t11 = datatree.AddCosh(arg);
          return datatree.AddTimes(darg, t11);
        case UnaryOpcode::tanh:
          t11 = datatree.AddTimes(this, this);
          t12 = datatree.AddMinus(datatree.One, t11);
          return datatree.AddTimes(darg, t12);
        case UnaryOpcode::acosh:
          t11 = datatree.AddSinh(this);
          return datatree.AddDivide(darg, t11);
        case UnaryOpcode::asinh:
          t11 = datatree.AddCosh(this);
          return datatree.AddDivide(darg, t11);
        case UnaryOpcode::atanh:
          t11 = datatree.AddTimes(arg, arg);
          t12 = datatree.AddMinus(datatree.One, t11);
          return datatree.AddDivide(darg, t12);
        case UnaryOpcode::sqrt:
          t11 = datatree.AddPlus(this, this);
          return datatree.AddDivide(darg, t11);
        case UnaryOpcode::cbrt:
          t11 = datatree.AddPower(arg, datatree.AddDivide(datatree.Two, datatree.Three));
          t12 = datatree.AddTimes(datatree.Three, t11);
          return datatree.AddDivide(darg, t12);
        case UnaryOpcode::abs:
          t11 = datatree.AddSign(arg);
          return datatree.AddTimes(t11, darg);
        case UnaryOpcode::sign:
          return datatree.Zero;
        case UnaryOpcode::steadyState:
          if (datatree.isDynamic())
            {
              if (datatree.getTypeByDerivID(deriv_id) == SymbolType::parameter)
                {
                  auto varg = dynamic_cast<VariableNode *>(arg);
                  if (!varg)
                    {
                      cerr << "UnaryOpNode::composeDerivatives: STEADY_STATE() should only be used on "
                           << "standalone variables (like STEADY_STATE(y)) to be derivable w.r.t. parameters" << endl;
                      exit(EXIT_FAILURE);
                    }
                  if (datatree.symbol_table.getType(varg->symb_id) == SymbolType::endogenous)
                    return datatree.AddSteadyStateParamDeriv(arg, datatree.getSymbIDByDerivID(deriv_id));
                  else
                    return datatree.Zero;
                }
              else
                return datatree.Zero;
            }
          else
            return darg;
        case UnaryOpcode::steadyStateParamDeriv:
          assert(datatree.isDynamic());
          if (datatree.getTypeByDerivID(deriv_id) == SymbolType::parameter)
            {
              auto varg = dynamic_cast<VariableNode *>(arg);
              assert(varg);
              assert(datatree.symbol_table.getType(varg->symb_id) == SymbolType::endogenous);
              return datatree.AddSteadyStateParam2ndDeriv(arg, param1_symb_id, datatree.getSymbIDByDerivID(deriv_id));
            }
          else
            return datatree.Zero;
        case UnaryOpcode::steadyStateParam2ndDeriv:
          assert(datatree.isDynamic());
          if (datatree.getTypeByDerivID(deriv_id) == SymbolType::parameter)
            {
              cerr << "3rd derivative of STEADY_STATE node w.r.t. three parameters not implemented" << endl;
              exit(EXIT_FAILURE);
            }
          else
            return datatree.Zero;
        case UnaryOpcode::expectation:
          cerr << "UnaryOpNode::composeDerivatives: not implemented on UnaryOpcode::expectation" << endl;
          exit(EXIT_FAILURE);
        case UnaryOpcode::erf:
        case UnaryOpcode::erfc:
          // x^2
          t11 = datatree.AddPower(arg, datatree.Two);
          // exp(x^2)
          t12 = datatree.AddExp(t11);
          // sqrt(pi)
          t11 = datatree.AddSqrt(datatree.Pi);
          // sqrt(pi)*exp(x^2)
          t13 = datatree.AddTimes(t11, t12);
          // 2/(sqrt(pi)*exp(x^2));
          t14 = datatree.AddDivide(datatree.Two, t13);
          // (2/(sqrt(pi)*exp(x^2)))*dx;
          t15 = datatree.AddTimes(t14, darg);
          if (op_code == UnaryOpcode::erf)
            return t15;
          else // erfc
            return datatree.AddUMinus(t15);
        case UnaryOpcode::diff:
          cerr << "UnaryOpNode::composeDerivatives: not implemented on UnaryOpcode::diff" << endl;
          exit(EXIT_FAILURE);
        case UnaryOpcode::adl:
          cerr << "UnaryOpNode::composeDerivatives: not implemented on UnaryOpcode::adl" << endl;
          exit(EXIT_FAILURE);
        }
      // Suppress GCC warning
      exit(EXIT_FAILURE);
    }
    
    expr_t
    UnaryOpNode::computeDerivative(int deriv_id)
    {
      expr_t darg = arg->getDerivative(deriv_id);
      return composeDerivatives(darg, deriv_id);
    }
    
    int
    UnaryOpNode::cost(const map<pair<int, int>, temporary_terms_t> &temp_terms_map, bool is_matlab) const
    {
      // For a temporary term, the cost is null
      for (const auto &it : temp_terms_map)
        if (it.second.find(const_cast<UnaryOpNode *>(this)) != it.second.end())
          return 0;
    
      return cost(arg->cost(temp_terms_map, is_matlab), is_matlab);
    }
    
    int
    UnaryOpNode::cost(const vector<vector<temporary_terms_t>> &blocks_temporary_terms, bool is_matlab) const
    {
      // For a temporary term, the cost is null
      for (const auto &blk_tt : blocks_temporary_terms)
        for (const auto &eq_tt : blk_tt)
          if (eq_tt.find(const_cast<UnaryOpNode *>(this)) != eq_tt.end())
            return 0;
    
      return cost(arg->cost(blocks_temporary_terms, is_matlab), is_matlab);
    }
    
    int
    UnaryOpNode::cost(int cost, bool is_matlab) const
    {
      if (op_code == UnaryOpcode::uminus && dynamic_cast<NumConstNode *>(arg))
        return 0; // Cost is zero for a negative constant, as for a positive one
    
      if (is_matlab)
        // Cost for Matlab files
        switch (op_code)
          {
          case UnaryOpcode::uminus:
          case UnaryOpcode::sign:
            return cost + 70;
          case UnaryOpcode::exp:
            return cost + 160;
          case UnaryOpcode::log:
            return cost + 300;
          case UnaryOpcode::log10:
          case UnaryOpcode::erf:
          case UnaryOpcode::erfc:
            return cost + 16000;
          case UnaryOpcode::cos:
          case UnaryOpcode::sin:
          case UnaryOpcode::cosh:
            return cost + 210;
          case UnaryOpcode::tan:
            return cost + 230;
          case UnaryOpcode::acos:
            return cost + 300;
          case UnaryOpcode::asin:
            return cost + 310;
          case UnaryOpcode::atan:
            return cost + 140;
          case UnaryOpcode::sinh:
            return cost + 240;
          case UnaryOpcode::tanh:
            return cost + 190;
          case UnaryOpcode::acosh:
            return cost + 770;
          case UnaryOpcode::asinh:
            return cost + 460;
          case UnaryOpcode::atanh:
            return cost + 350;
          case UnaryOpcode::sqrt:
          case UnaryOpcode::cbrt:
          case UnaryOpcode::abs:
            return cost + 570;
          case UnaryOpcode::steadyState:
          case UnaryOpcode::steadyStateParamDeriv:
          case UnaryOpcode::steadyStateParam2ndDeriv:
          case UnaryOpcode::expectation:
            return cost;
          case UnaryOpcode::diff:
            cerr << "UnaryOpNode::cost: not implemented on UnaryOpcode::diff" << endl;
            exit(EXIT_FAILURE);
          case UnaryOpcode::adl:
            cerr << "UnaryOpNode::cost: not implemented on UnaryOpcode::adl" << endl;
            exit(EXIT_FAILURE);
          }
      else
        // Cost for C files
        switch (op_code)
          {
          case UnaryOpcode::uminus:
          case UnaryOpcode::sign:
            return cost + 3;
          case UnaryOpcode::exp:
          case UnaryOpcode::acosh:
            return cost + 210;
          case UnaryOpcode::log:
            return cost + 137;
          case UnaryOpcode::log10:
            return cost + 139;
          case UnaryOpcode::cos:
          case UnaryOpcode::sin:
            return cost + 160;
          case UnaryOpcode::tan:
            return cost + 170;
          case UnaryOpcode::acos:
          case UnaryOpcode::atan:
            return cost + 190;
          case UnaryOpcode::asin:
            return cost + 180;
          case UnaryOpcode::cosh:
          case UnaryOpcode::sinh:
          case UnaryOpcode::tanh:
          case UnaryOpcode::erf:
          case UnaryOpcode::erfc:
            return cost + 240;
          case UnaryOpcode::asinh:
            return cost + 220;
          case UnaryOpcode::atanh:
            return cost + 150;
          case UnaryOpcode::sqrt:
          case UnaryOpcode::cbrt:
          case UnaryOpcode::abs:
            return cost + 90;
          case UnaryOpcode::steadyState:
          case UnaryOpcode::steadyStateParamDeriv:
          case UnaryOpcode::steadyStateParam2ndDeriv:
          case UnaryOpcode::expectation:
            return cost;
          case UnaryOpcode::diff:
            cerr << "UnaryOpNode::cost: not implemented on UnaryOpcode::diff" << endl;
            exit(EXIT_FAILURE);
          case UnaryOpcode::adl:
            cerr << "UnaryOpNode::cost: not implemented on UnaryOpcode::adl" << endl;
            exit(EXIT_FAILURE);
          }
      exit(EXIT_FAILURE);
    }
    
    void
    UnaryOpNode::computeTemporaryTerms(const pair<int, int> &derivOrder,
                                       map<pair<int, int>, temporary_terms_t> &temp_terms_map,
                                       map<expr_t, pair<int, pair<int, int>>> &reference_count,
                                       bool is_matlab) const
    {
      expr_t this2 = const_cast<UnaryOpNode *>(this);
      if (auto it = reference_count.find(this2);
          it == reference_count.end())
        {
          reference_count[this2] = { 1, derivOrder };
          arg->computeTemporaryTerms(derivOrder, temp_terms_map, reference_count, is_matlab);
        }
      else
        {
          auto &[nref, min_order] = it->second;
          nref++;
          if (nref * cost(temp_terms_map, is_matlab) > min_cost(is_matlab))
            temp_terms_map[min_order].insert(this2);
        }
    }
    
    void
    UnaryOpNode::computeBlockTemporaryTerms(int blk, int eq, vector<vector<temporary_terms_t>> &blocks_temporary_terms,
                                            map<expr_t, tuple<int, int, int>> &reference_count) const
    {
      expr_t this2 = const_cast<UnaryOpNode *>(this);
      if (auto it = reference_count.find(this2);
          it == reference_count.end())
        {
          reference_count[this2] = { 1, blk, eq };
          arg->computeBlockTemporaryTerms(blk, eq, blocks_temporary_terms, reference_count);
        }
      else
        {
          auto &[nref, first_blk, first_eq] = it->second;
          nref++;
          if (nref * cost(blocks_temporary_terms, false) > min_cost_c)
            blocks_temporary_terms[first_blk][first_eq].insert(this2);
        }
    }
    
    bool
    UnaryOpNode::containsExternalFunction() const
    {
      return arg->containsExternalFunction();
    }
    
    void
    UnaryOpNode::writeJsonAST(ostream &output) const
    {
      output << R"({"node_type" : "UnaryOpNode", "op" : ")";
      switch (op_code)
        {
        case UnaryOpcode::uminus:
          output << "uminus";
          break;
        case UnaryOpcode::exp:
          output << "exp";
          break;
        case UnaryOpcode::log:
          output << "log";
          break;
        case UnaryOpcode::log10:
          output << "log10";
          break;
        case UnaryOpcode::cos:
          output << "cos";
          break;
        case UnaryOpcode::sin:
          output << "sin";
          break;
        case UnaryOpcode::tan:
          output << "tan";
          break;
        case UnaryOpcode::acos:
          output << "acos";
          break;
        case UnaryOpcode::asin:
          output << "asin";
          break;
        case UnaryOpcode::atan:
          output << "atan";
          break;
        case UnaryOpcode::cosh:
          output << "cosh";
          break;
        case UnaryOpcode::sinh:
          output << "sinh";
          break;
        case UnaryOpcode::tanh:
          output << "tanh";
          break;
        case UnaryOpcode::acosh:
          output << "acosh";
          break;
        case UnaryOpcode::asinh:
          output << "asinh";
          break;
        case UnaryOpcode::atanh:
          output << "atanh";
          break;
        case UnaryOpcode::sqrt:
          output << "sqrt";
          break;
        case UnaryOpcode::cbrt:
          output << "cbrt";
          break;
        case UnaryOpcode::abs:
          output << "abs";
          break;
        case UnaryOpcode::sign:
          output << "sign";
          break;
        case UnaryOpcode::diff:
          output << "diff";
          break;
        case UnaryOpcode::adl:
          output << "adl";
          break;
        case UnaryOpcode::steadyState:
          output << "steady_state";
        case UnaryOpcode::steadyStateParamDeriv:
          output << "steady_state_param_deriv";
          break;
        case UnaryOpcode::steadyStateParam2ndDeriv:
          output << "steady_state_param_second_deriv";
          break;
        case UnaryOpcode::expectation:
          output << "expectation";
          break;
        case UnaryOpcode::erf:
          output << "erf";
          break;
        case UnaryOpcode::erfc:
          output << "erfc";
          break;
        }
      output << R"(", "arg" : )";
      arg->writeJsonAST(output);
      switch (op_code)
        {
        case UnaryOpcode::adl:
          output << R"(, "adl_param_name" : ")" << adl_param_name << R"(")"
                 << R"(, "lags" : [)";
          for (auto it = adl_lags.begin(); it != adl_lags.end(); ++it)
            {
              if (it != adl_lags.begin())
                output << ", ";
              output << *it;
            }
          output << "]";
          break;
        default:
          break;
        }
      output << "}";
    }
    
    void
    UnaryOpNode::writeJsonOutput(ostream &output,
                                 const temporary_terms_t &temporary_terms,
                                 const deriv_node_temp_terms_t &tef_terms,
                                 bool isdynamic) const
    {
      if (temporary_terms.find(const_cast<UnaryOpNode *>(this)) != temporary_terms.end())
        {
          output << "T" << idx;
          return;
        }
    
      // Always put parenthesis around uminus nodes
      if (op_code == UnaryOpcode::uminus)
        output << "(";
    
      switch (op_code)
        {
        case UnaryOpcode::uminus:
          output << "-";
          break;
        case UnaryOpcode::exp:
          output << "exp";
          break;
        case UnaryOpcode::log:
          output << "log";
          break;
        case UnaryOpcode::log10:
          output << "log10";
          break;
        case UnaryOpcode::cos:
          output << "cos";
          break;
        case UnaryOpcode::sin:
          output << "sin";
          break;
        case UnaryOpcode::tan:
          output << "tan";
          break;
        case UnaryOpcode::acos:
          output << "acos";
          break;
        case UnaryOpcode::asin:
          output << "asin";
          break;
        case UnaryOpcode::atan:
          output << "atan";
          break;
        case UnaryOpcode::cosh:
          output << "cosh";
          break;
        case UnaryOpcode::sinh:
          output << "sinh";
          break;
        case UnaryOpcode::tanh:
          output << "tanh";
          break;
        case UnaryOpcode::acosh:
          output << "acosh";
          break;
        case UnaryOpcode::asinh:
          output << "asinh";
          break;
        case UnaryOpcode::atanh:
          output << "atanh";
          break;
        case UnaryOpcode::sqrt:
          output << "sqrt";
          break;
        case UnaryOpcode::cbrt:
          output << "cbrt";
          break;
        case UnaryOpcode::abs:
          output << "abs";
          break;
        case UnaryOpcode::sign:
          output << "sign";
          break;
        case UnaryOpcode::diff:
          output << "diff";
          break;
        case UnaryOpcode::adl:
          output << "adl(";
          arg->writeJsonOutput(output, temporary_terms, tef_terms);
          output << ", '" << adl_param_name << "', [";
          for (auto it = adl_lags.begin(); it != adl_lags.end(); ++it)
            {
              if (it != adl_lags.begin())
                output << ", ";
              output << *it;
            }
          output << "])";
          return;
        case UnaryOpcode::steadyState:
          output << "(";
          arg->writeJsonOutput(output, temporary_terms, tef_terms, isdynamic);
          output << ")";
          return;
        case UnaryOpcode::steadyStateParamDeriv:
          {
            auto varg = dynamic_cast<VariableNode *>(arg);
            assert(varg);
            assert(datatree.symbol_table.getType(varg->symb_id) == SymbolType::endogenous);
            assert(datatree.symbol_table.getType(param1_symb_id) == SymbolType::parameter);
            int tsid_endo = datatree.symbol_table.getTypeSpecificID(varg->symb_id);
            int tsid_param = datatree.symbol_table.getTypeSpecificID(param1_symb_id);
            output << "ss_param_deriv(" << tsid_endo+1 << "," << tsid_param+1 << ")";
          }
          return;
        case UnaryOpcode::steadyStateParam2ndDeriv:
          {
            auto varg = dynamic_cast<VariableNode *>(arg);
            assert(varg);
            assert(datatree.symbol_table.getType(varg->symb_id) == SymbolType::endogenous);
            assert(datatree.symbol_table.getType(param1_symb_id) == SymbolType::parameter);
            assert(datatree.symbol_table.getType(param2_symb_id) == SymbolType::parameter);
            int tsid_endo = datatree.symbol_table.getTypeSpecificID(varg->symb_id);
            int tsid_param1 = datatree.symbol_table.getTypeSpecificID(param1_symb_id);
            int tsid_param2 = datatree.symbol_table.getTypeSpecificID(param2_symb_id);
            output << "ss_param_2nd_deriv(" << tsid_endo+1 << "," << tsid_param1+1
                   << "," << tsid_param2+1 << ")";
          }
          return;
        case UnaryOpcode::expectation:
          output << "EXPECTATION(" << expectation_information_set << ")";
          break;
        case UnaryOpcode::erf:
          output << "erf";
          break;
        case UnaryOpcode::erfc:
          output << "erfc";
          break;
        }
    
      bool close_parenthesis = false;
    
      /* Enclose argument with parentheses if:
         - current opcode is not uminus, or
         - current opcode is uminus and argument has lowest precedence
      */
      if (op_code != UnaryOpcode::uminus
          || (op_code == UnaryOpcode::uminus
              && arg->precedenceJson(temporary_terms) < precedenceJson(temporary_terms)))
        {
          output << "(";
          close_parenthesis = true;
        }
    
      // Write argument
      arg->writeJsonOutput(output, temporary_terms, tef_terms, isdynamic);
    
      if (close_parenthesis)
        output << ")";
    
      // Close parenthesis for uminus
      if (op_code == UnaryOpcode::uminus)
        output << ")";
    }
    
    void
    UnaryOpNode::writeOutput(ostream &output, ExprNodeOutputType output_type,
                             const temporary_terms_t &temporary_terms,
                             const temporary_terms_idxs_t &temporary_terms_idxs,
                             const deriv_node_temp_terms_t &tef_terms) const
    {
      if (checkIfTemporaryTermThenWrite(output, output_type, temporary_terms, temporary_terms_idxs))
        return;
    
      // Always put parenthesis around uminus nodes
      if (op_code == UnaryOpcode::uminus)
        output << LEFT_PAR(output_type);
    
      switch (op_code)
        {
        case UnaryOpcode::uminus:
          output << "-";
          break;
        case UnaryOpcode::exp:
          if (isLatexOutput(output_type))
            output << R"(\exp)";
          else
            output << "exp";
          break;
        case UnaryOpcode::log:
          if (isLatexOutput(output_type))
            output << R"(\log)";
          else
            output << "log";
          break;
        case UnaryOpcode::log10:
          if (isLatexOutput(output_type))
            output << R"(\log_{10})";
          else
            output << "log10";
          break;
        case UnaryOpcode::cos:
          if (isLatexOutput(output_type))
            output << R"(\cos)";
          else
            output << "cos";
          break;
        case UnaryOpcode::sin:
          if (isLatexOutput(output_type))
            output << R"(\sin)";
          else
            output << "sin";
          break;
        case UnaryOpcode::tan:
          if (isLatexOutput(output_type))
            output << R"(\tan)";
          else
            output << "tan";
          break;
        case UnaryOpcode::acos:
          output << "acos";
          break;
        case UnaryOpcode::asin:
          output << "asin";
          break;
        case UnaryOpcode::atan:
          output << "atan";
          break;
        case UnaryOpcode::cosh:
          output << "cosh";
          break;
        case UnaryOpcode::sinh:
          output << "sinh";
          break;
        case UnaryOpcode::tanh:
          output << "tanh";
          break;
        case UnaryOpcode::acosh:
          output << "acosh";
          break;
        case UnaryOpcode::asinh:
          output << "asinh";
          break;
        case UnaryOpcode::atanh:
          output << "atanh";
          break;
        case UnaryOpcode::sqrt:
          if (isLatexOutput(output_type))
            {
              output << R"(\sqrt{)";
              arg->writeOutput(output, output_type, temporary_terms, temporary_terms_idxs, tef_terms);
              output << "}";
              return;
            }
          output << "sqrt";
          break;
        case UnaryOpcode::cbrt:
          if (isMatlabOutput(output_type))
            {
              output << "nthroot(";
              arg->writeOutput(output, output_type, temporary_terms, temporary_terms_idxs, tef_terms);
              output << ", 3)";
              return;
            }
          else if (isLatexOutput(output_type))
            {
              output << R"(\sqrt[3]{)";
              arg->writeOutput(output, output_type, temporary_terms, temporary_terms_idxs, tef_terms);
              output << "}";
              return;
            }
          else
            output << "cbrt";
          break;
        case UnaryOpcode::abs:
          output << "abs";
          break;
        case UnaryOpcode::sign:
          if (output_type == ExprNodeOutputType::CDynamicModel || output_type == ExprNodeOutputType::CStaticModel)
            output << "copysign";
          else
            output << "sign";
          break;
        case UnaryOpcode::steadyState:
          ExprNodeOutputType new_output_type;
          switch (output_type)
            {
            case ExprNodeOutputType::matlabDynamicModel:
            case ExprNodeOutputType::occbinDifferenceFile:
              new_output_type = ExprNodeOutputType::matlabDynamicSteadyStateOperator;
              break;
            case ExprNodeOutputType::latexDynamicModel:
              new_output_type = ExprNodeOutputType::latexDynamicSteadyStateOperator;
              break;
            case ExprNodeOutputType::CDynamicModel:
              new_output_type = ExprNodeOutputType::CDynamicSteadyStateOperator;
              break;
            case ExprNodeOutputType::juliaDynamicModel:
              new_output_type = ExprNodeOutputType::juliaDynamicSteadyStateOperator;
              break;
            default:
              new_output_type = output_type;
              break;
            }
          output << "(";
          arg->writeOutput(output, new_output_type, temporary_terms, temporary_terms_idxs, tef_terms);
          output << ")";
          return;
        case UnaryOpcode::steadyStateParamDeriv:
          {
            auto varg = dynamic_cast<VariableNode *>(arg);
            assert(varg);
            assert(datatree.symbol_table.getType(varg->symb_id) == SymbolType::endogenous);
            assert(datatree.symbol_table.getType(param1_symb_id) == SymbolType::parameter);
            int tsid_endo = datatree.symbol_table.getTypeSpecificID(varg->symb_id);
            int tsid_param = datatree.symbol_table.getTypeSpecificID(param1_symb_id);
            assert(isMatlabOutput(output_type));
            output << "ss_param_deriv(" << tsid_endo+1 << "," << tsid_param+1 << ")";
          }
          return;
        case UnaryOpcode::steadyStateParam2ndDeriv:
          {
            auto varg = dynamic_cast<VariableNode *>(arg);
            assert(varg);
            assert(datatree.symbol_table.getType(varg->symb_id) == SymbolType::endogenous);
            assert(datatree.symbol_table.getType(param1_symb_id) == SymbolType::parameter);
            assert(datatree.symbol_table.getType(param2_symb_id) == SymbolType::parameter);
            int tsid_endo = datatree.symbol_table.getTypeSpecificID(varg->symb_id);
            int tsid_param1 = datatree.symbol_table.getTypeSpecificID(param1_symb_id);
            int tsid_param2 = datatree.symbol_table.getTypeSpecificID(param2_symb_id);
            assert(isMatlabOutput(output_type));
            output << "ss_param_2nd_deriv(" << tsid_endo+1 << "," << tsid_param1+1
                   << "," << tsid_param2+1 << ")";
          }
          return;
        case UnaryOpcode::expectation:
          if (!isLatexOutput(output_type))
            {
              cerr << "UnaryOpNode::writeOutput: not implemented on UnaryOpcode::expectation" << endl;
              exit(EXIT_FAILURE);
            }
          output << R"(\mathbb{E}_{t)";
          if (expectation_information_set != 0)
            {
              if (expectation_information_set > 0)
                output << "+";
              output << expectation_information_set;
            }
          output << "}";
          break;
        case UnaryOpcode::erf:
          output << "erf";
          break;
        case UnaryOpcode::erfc:
          output << "erfc";
          break;
        case UnaryOpcode::diff:
          output << "diff";
          break;
        case UnaryOpcode::adl:
          output << "adl";
          break;
        }
    
      bool close_parenthesis = false;
    
      /* Enclose argument with parentheses if:
         - current opcode is not uminus, or
         - current opcode is uminus and argument has lowest precedence
      */
      if (op_code != UnaryOpcode::uminus
          || (op_code == UnaryOpcode::uminus
              && arg->precedence(output_type, temporary_terms) < precedence(output_type, temporary_terms)))
        {
          output << LEFT_PAR(output_type);
          if (op_code == UnaryOpcode::sign && (output_type == ExprNodeOutputType::CDynamicModel || output_type == ExprNodeOutputType::CStaticModel))
            output << "1.0,";
          close_parenthesis = true;
        }
    
      // Write argument
      arg->writeOutput(output, output_type, temporary_terms, temporary_terms_idxs, tef_terms);
    
      if (close_parenthesis)
        output << RIGHT_PAR(output_type);
    
      // Close parenthesis for uminus
      if (op_code == UnaryOpcode::uminus)
        output << RIGHT_PAR(output_type);
    }
    
    void
    UnaryOpNode::writeExternalFunctionOutput(ostream &output, ExprNodeOutputType output_type,
                                             const temporary_terms_t &temporary_terms,
                                             const temporary_terms_idxs_t &temporary_terms_idxs,
                                             deriv_node_temp_terms_t &tef_terms) const
    {
      arg->writeExternalFunctionOutput(output, output_type, temporary_terms, temporary_terms_idxs, tef_terms);
    }
    
    void
    UnaryOpNode::writeJsonExternalFunctionOutput(vector<string> &efout,
                                                 const temporary_terms_t &temporary_terms,
                                                 deriv_node_temp_terms_t &tef_terms,
                                                 bool isdynamic) const
    {
      arg->writeJsonExternalFunctionOutput(efout, temporary_terms, tef_terms, isdynamic);
    }
    
    void
    UnaryOpNode::compileExternalFunctionOutput(ostream &CompileCode, unsigned int &instruction_number,
                                               bool lhs_rhs, const temporary_terms_t &temporary_terms,
                                               const temporary_terms_idxs_t &temporary_terms_idxs, bool dynamic, bool steady_dynamic,
                                               deriv_node_temp_terms_t &tef_terms) const
    {
      arg->compileExternalFunctionOutput(CompileCode, instruction_number, lhs_rhs, temporary_terms,
                                         temporary_terms_idxs, dynamic, steady_dynamic, tef_terms);
    }
    
    double
    UnaryOpNode::eval_opcode(UnaryOpcode op_code, double v) noexcept(false)
    {
      switch (op_code)
        {
        case UnaryOpcode::uminus:
          return -v;
        case UnaryOpcode::exp:
          return exp(v);
        case UnaryOpcode::log:
          return log(v);
        case UnaryOpcode::log10:
          return log10(v);
        case UnaryOpcode::cos:
          return cos(v);
        case UnaryOpcode::sin:
          return sin(v);
        case UnaryOpcode::tan:
          return tan(v);
        case UnaryOpcode::acos:
          return acos(v);
        case UnaryOpcode::asin:
          return asin(v);
        case UnaryOpcode::atan:
          return atan(v);
        case UnaryOpcode::cosh:
          return cosh(v);
        case UnaryOpcode::sinh:
          return sinh(v);
        case UnaryOpcode::tanh:
          return tanh(v);
        case UnaryOpcode::acosh:
          return acosh(v);
        case UnaryOpcode::asinh:
          return asinh(v);
        case UnaryOpcode::atanh:
          return atanh(v);
        case UnaryOpcode::sqrt:
          return sqrt(v);
        case UnaryOpcode::cbrt:
          return cbrt(v);
        case UnaryOpcode::abs:
          return abs(v);
        case UnaryOpcode::sign:
          return (v > 0) ? 1 : ((v < 0) ? -1 : 0);
        case UnaryOpcode::steadyState:
          return v;
        case UnaryOpcode::steadyStateParamDeriv:
          cerr << "UnaryOpNode::eval_opcode: not implemented on UnaryOpcode::steadyStateParamDeriv" << endl;
          exit(EXIT_FAILURE);
        case UnaryOpcode::steadyStateParam2ndDeriv:
          cerr << "UnaryOpNode::eval_opcode: not implemented on UnaryOpcode::steadyStateParam2ndDeriv" << endl;
          exit(EXIT_FAILURE);
        case UnaryOpcode::expectation:
          cerr << "UnaryOpNode::eval_opcode: not implemented on UnaryOpcode::expectation" << endl;
          exit(EXIT_FAILURE);
        case UnaryOpcode::erf:
          return erf(v);
        case UnaryOpcode::erfc:
          return erfc(v);
        case UnaryOpcode::diff:
          cerr << "UnaryOpNode::eval_opcode: not implemented on UnaryOpcode::diff" << endl;
          exit(EXIT_FAILURE);
        case UnaryOpcode::adl:
          cerr << "UnaryOpNode::eval_opcode: not implemented on UnaryOpcode::adl" << endl;
          exit(EXIT_FAILURE);
        }
      // Suppress GCC warning
      exit(EXIT_FAILURE);
    }
    
    double
    UnaryOpNode::eval(const eval_context_t &eval_context) const noexcept(false)
    {
      double v = arg->eval(eval_context);
      return eval_opcode(op_code, v);
    }
    
    void
    UnaryOpNode::compile(ostream &CompileCode, unsigned int &instruction_number,
                         bool lhs_rhs, const temporary_terms_t &temporary_terms,
                         const temporary_terms_idxs_t &temporary_terms_idxs, bool dynamic, bool steady_dynamic,
                         const deriv_node_temp_terms_t &tef_terms) const
    {
      if (auto this2 = const_cast<UnaryOpNode *>(this);
          temporary_terms.find(this2) != temporary_terms.end())
        {
          if (dynamic)
            {
              FLDT_ fldt(temporary_terms_idxs.at(this2));
              fldt.write(CompileCode, instruction_number);
            }
          else
            {
              FLDST_ fldst(temporary_terms_idxs.at(this2));
              fldst.write(CompileCode, instruction_number);
            }
          return;
        }
      if (op_code == UnaryOpcode::steadyState)
        arg->compile(CompileCode, instruction_number, lhs_rhs, temporary_terms, temporary_terms_idxs, dynamic, true, tef_terms);
      else
        {
          arg->compile(CompileCode, instruction_number, lhs_rhs, temporary_terms, temporary_terms_idxs, dynamic, steady_dynamic, tef_terms);
          FUNARY_ funary{static_cast<uint8_t>(op_code)};
          funary.write(CompileCode, instruction_number);
        }
    }
    
    void
    UnaryOpNode::collectVARLHSVariable(set<expr_t> &result) const
    {
      if (op_code == UnaryOpcode::diff)
        result.insert(const_cast<UnaryOpNode *>(this));
      else
        arg->collectVARLHSVariable(result);
    }
    
    void
    UnaryOpNode::collectDynamicVariables(SymbolType type_arg, set<pair<int, int>> &result) const
    {
      arg->collectDynamicVariables(type_arg, result);
    }
    
    void
    UnaryOpNode::computeSubExprContainingVariable(int symb_id, int lag, set<expr_t> &contain_var) const
    {
      arg->computeSubExprContainingVariable(symb_id, lag, contain_var);
      if (contain_var.count(arg) > 0)
        contain_var.insert(const_cast<UnaryOpNode *>(this));
    }
    
    BinaryOpNode *
    UnaryOpNode::normalizeEquationHelper(const set<expr_t> &contain_var, expr_t rhs) const
    {
      assert(contain_var.count(const_cast<UnaryOpNode *>(this)) > 0);
    
      switch (op_code)
        {
        case UnaryOpcode::uminus:
          rhs = datatree.AddUMinus(rhs);
          break;
        case UnaryOpcode::exp:
          rhs = datatree.AddLog(rhs);
          break;
        case UnaryOpcode::log:
          rhs = datatree.AddExp(rhs);
          break;
        case UnaryOpcode::log10:
          rhs = datatree.AddPower(datatree.AddNonNegativeConstant("10"), rhs);
          break;
        case UnaryOpcode::cos:
          rhs = datatree.AddAcos(rhs);
          break;
        case UnaryOpcode::sin:
          rhs = datatree.AddAsin(rhs);
          break;
        case UnaryOpcode::tan:
          rhs = datatree.AddAtan(rhs);
          break;
        case UnaryOpcode::acos:
          rhs = datatree.AddCos(rhs);
          break;
        case UnaryOpcode::asin:
          rhs = datatree.AddSin(rhs);
          break;
        case UnaryOpcode::atan:
          rhs = datatree.AddTan(rhs);
          break;
        case UnaryOpcode::cosh:
          rhs = datatree.AddAcosh(rhs);
          break;
        case UnaryOpcode::sinh:
          rhs = datatree.AddAsinh(rhs);
          break;
        case UnaryOpcode::tanh:
          rhs = datatree.AddAtanh(rhs);
          break;
        case UnaryOpcode::acosh:
          rhs = datatree.AddCosh(rhs);
          break;
        case UnaryOpcode::asinh:
          rhs = datatree.AddSinh(rhs);
          break;
        case UnaryOpcode::atanh:
          rhs = datatree.AddTanh(rhs);
          break;
        case UnaryOpcode::sqrt:
          rhs = datatree.AddPower(rhs, datatree.Two);
          break;
        case UnaryOpcode::cbrt:
          rhs = datatree.AddPower(rhs, datatree.Three);
          break;
        default:
          throw NormalizationFailed();
        }
    
      return arg->normalizeEquationHelper(contain_var, rhs);
    }
    
    expr_t
    UnaryOpNode::getChainRuleDerivative(int deriv_id, const map<int, BinaryOpNode *> &recursive_variables)
    {
      expr_t darg = arg->getChainRuleDerivative(deriv_id, recursive_variables);
      return composeDerivatives(darg, deriv_id);
    }
    
    expr_t
    UnaryOpNode::buildSimilarUnaryOpNode(expr_t alt_arg, DataTree &alt_datatree) const
    {
      switch (op_code)
        {
        case UnaryOpcode::uminus:
          return alt_datatree.AddUMinus(alt_arg);
        case UnaryOpcode::exp:
          return alt_datatree.AddExp(alt_arg);
        case UnaryOpcode::log:
          return alt_datatree.AddLog(alt_arg);
        case UnaryOpcode::log10:
          return alt_datatree.AddLog10(alt_arg);
        case UnaryOpcode::cos:
          return alt_datatree.AddCos(alt_arg);
        case UnaryOpcode::sin:
          return alt_datatree.AddSin(alt_arg);
        case UnaryOpcode::tan:
          return alt_datatree.AddTan(alt_arg);
        case UnaryOpcode::acos:
          return alt_datatree.AddAcos(alt_arg);
        case UnaryOpcode::asin:
          return alt_datatree.AddAsin(alt_arg);
        case UnaryOpcode::atan:
          return alt_datatree.AddAtan(alt_arg);
        case UnaryOpcode::cosh:
          return alt_datatree.AddCosh(alt_arg);
        case UnaryOpcode::sinh:
          return alt_datatree.AddSinh(alt_arg);
        case UnaryOpcode::tanh:
          return alt_datatree.AddTanh(alt_arg);
        case UnaryOpcode::acosh:
          return alt_datatree.AddAcosh(alt_arg);
        case UnaryOpcode::asinh:
          return alt_datatree.AddAsinh(alt_arg);
        case UnaryOpcode::atanh:
          return alt_datatree.AddAtanh(alt_arg);
        case UnaryOpcode::sqrt:
          return alt_datatree.AddSqrt(alt_arg);
        case UnaryOpcode::cbrt:
          return alt_datatree.AddCbrt(alt_arg);
        case UnaryOpcode::abs:
          return alt_datatree.AddAbs(alt_arg);
        case UnaryOpcode::sign:
          return alt_datatree.AddSign(alt_arg);
        case UnaryOpcode::steadyState:
          return alt_datatree.AddSteadyState(alt_arg);
        case UnaryOpcode::steadyStateParamDeriv:
          cerr << "UnaryOpNode::buildSimilarUnaryOpNode: UnaryOpcode::steadyStateParamDeriv can't be translated" << endl;
          exit(EXIT_FAILURE);
        case UnaryOpcode::steadyStateParam2ndDeriv:
          cerr << "UnaryOpNode::buildSimilarUnaryOpNode: UnaryOpcode::steadyStateParam2ndDeriv can't be translated" << endl;
          exit(EXIT_FAILURE);
        case UnaryOpcode::expectation:
          return alt_datatree.AddExpectation(expectation_information_set, alt_arg);
        case UnaryOpcode::erf:
          return alt_datatree.AddErf(alt_arg);
        case UnaryOpcode::erfc:
          return alt_datatree.AddErfc(alt_arg);
        case UnaryOpcode::diff:
          return alt_datatree.AddDiff(alt_arg);
        case UnaryOpcode::adl:
          return alt_datatree.AddAdl(alt_arg, adl_param_name, adl_lags);
        }
      // Suppress GCC warning
      exit(EXIT_FAILURE);
    }
    
    expr_t
    UnaryOpNode::toStatic(DataTree &static_datatree) const
    {
      expr_t sarg = arg->toStatic(static_datatree);
      return buildSimilarUnaryOpNode(sarg, static_datatree);
    }
    
    void
    UnaryOpNode::computeXrefs(EquationInfo &ei) const
    {
      arg->computeXrefs(ei);
    }
    
    expr_t
    UnaryOpNode::clone(DataTree &datatree) const
    {
      expr_t substarg = arg->clone(datatree);
      return buildSimilarUnaryOpNode(substarg, datatree);
    }
    
    int
    UnaryOpNode::maxEndoLead() const
    {
      return arg->maxEndoLead();
    }
    
    int
    UnaryOpNode::maxExoLead() const
    {
      return arg->maxExoLead();
    }
    
    int
    UnaryOpNode::maxEndoLag() const
    {
      return arg->maxEndoLag();
    }
    
    int
    UnaryOpNode::maxExoLag() const
    {
      return arg->maxExoLag();
    }
    
    int
    UnaryOpNode::maxLead() const
    {
      return arg->maxLead();
    }
    
    int
    UnaryOpNode::maxLag() const
    {
      return arg->maxLag();
    }
    
    int
    UnaryOpNode::maxLagWithDiffsExpanded() const
    {
      if (op_code == UnaryOpcode::diff)
        return arg->maxLagWithDiffsExpanded() + 1;
      return arg->maxLagWithDiffsExpanded();
    }
    
    expr_t
    UnaryOpNode::undiff() const
    {
      if (op_code == UnaryOpcode::diff)
        return arg;
      return arg->undiff();
    }
    
    int
    UnaryOpNode::VarMaxLag(const set<expr_t> &lhs_lag_equiv) const
    {
      auto [lag_equiv_repr, index] = getLagEquivalenceClass();
      if (lhs_lag_equiv.find(lag_equiv_repr) == lhs_lag_equiv.end())
        return 0;
      return arg->maxLag();
    }
    
    expr_t
    UnaryOpNode::substituteAdl() const
    {
      if (op_code != UnaryOpcode::adl)
        {
          expr_t argsubst = arg->substituteAdl();
          return buildSimilarUnaryOpNode(argsubst, datatree);
        }
    
      expr_t arg1subst = arg->substituteAdl();
      expr_t retval = nullptr;
      ostringstream inttostr;
    
      for (auto it = adl_lags.begin(); it != adl_lags.end(); ++it)
        if (it == adl_lags.begin())
          {
            inttostr << *it;
            retval = datatree.AddTimes(datatree.AddVariable(datatree.symbol_table.getID(adl_param_name + "_lag_" + inttostr.str()), 0),
                                       arg1subst->decreaseLeadsLags(*it));
          }
        else
          {
            inttostr.clear();
            inttostr.str("");
            inttostr << *it;
            retval = datatree.AddPlus(retval,
                                      datatree.AddTimes(datatree.AddVariable(datatree.symbol_table.getID(adl_param_name + "_lag_"
                                                                                                         + inttostr.str()), 0),
                                                        arg1subst->decreaseLeadsLags(*it)));
          }
      return retval;
    }
    
    expr_t
    UnaryOpNode::substituteModelLocalVariables() const
    {
      expr_t argsubst = arg->substituteModelLocalVariables();
      return buildSimilarUnaryOpNode(argsubst, datatree);
    }
    
    expr_t
    UnaryOpNode::substituteVarExpectation(const map<string, expr_t> &subst_table) const
    {
      expr_t argsubst = arg->substituteVarExpectation(subst_table);
      return buildSimilarUnaryOpNode(argsubst, datatree);
    }
    
    int
    UnaryOpNode::countDiffs() const
    {
      if (op_code == UnaryOpcode::diff)
        return arg->countDiffs() + 1;
      return arg->countDiffs();
    }
    
    bool
    UnaryOpNode::createAuxVarForUnaryOpNode() const
    {
      switch (op_code)
        {
        case UnaryOpcode::exp:
        case UnaryOpcode::log:
        case UnaryOpcode::log10:
        case UnaryOpcode::cos:
        case UnaryOpcode::sin:
        case UnaryOpcode::tan:
        case UnaryOpcode::acos:
        case UnaryOpcode::asin:
        case UnaryOpcode::atan:
        case UnaryOpcode::cosh:
        case UnaryOpcode::sinh:
        case UnaryOpcode::tanh:
        case UnaryOpcode::acosh:
        case UnaryOpcode::asinh:
        case UnaryOpcode::atanh:
        case UnaryOpcode::sqrt:
        case UnaryOpcode::cbrt:
        case UnaryOpcode::abs:
        case UnaryOpcode::sign:
        case UnaryOpcode::erf:
        case UnaryOpcode::erfc:
          return true;
        default:
          return false;
        }
    }
    
    void
    UnaryOpNode::findUnaryOpNodesForAuxVarCreation(lag_equivalence_table_t &nodes) const
    {
      arg->findUnaryOpNodesForAuxVarCreation(nodes);
    
      if (!this->createAuxVarForUnaryOpNode())
        return;
    
      auto [lag_equiv_repr, index] = getLagEquivalenceClass();
      nodes[lag_equiv_repr][index] = const_cast<UnaryOpNode *>(this);
    }
    
    void
    UnaryOpNode::findDiffNodes(lag_equivalence_table_t &nodes) const
    {
      arg->findDiffNodes(nodes);
    
      if (op_code != UnaryOpcode::diff)
        return;
    
      auto [lag_equiv_repr, index] = getLagEquivalenceClass();
      nodes[lag_equiv_repr][index] = const_cast<UnaryOpNode *>(this);
    }
    
    int
    UnaryOpNode::findTargetVariable(int lhs_symb_id) const
    {
      return arg->findTargetVariable(lhs_symb_id);
    }
    
    expr_t
    UnaryOpNode::substituteDiff(const lag_equivalence_table_t &nodes, subst_table_t &subst_table,
                                vector<BinaryOpNode *> &neweqs) const
    {
      // If this is not a diff node, then substitute recursively and return
      expr_t argsubst = arg->substituteDiff(nodes, subst_table, neweqs);
      if (op_code != UnaryOpcode::diff)
        return buildSimilarUnaryOpNode(argsubst, datatree);
    
      if (auto sit = subst_table.find(this);
          sit != subst_table.end())
        return const_cast<VariableNode *>(sit->second);
    
      auto [lag_equiv_repr, index] = getLagEquivalenceClass();
      auto it = nodes.find(lag_equiv_repr);
      if (it == nodes.end() || it->second.find(index) == it->second.end()
          || it->second.at(index) != this)
        {
          /* diff does not appear in VAR equations, so simply create aux var and return.
             Once the comparison of expression nodes works, come back and remove
             this part, folding into the next loop. */
          int symb_id = datatree.symbol_table.addDiffAuxiliaryVar(argsubst->idx, const_cast<UnaryOpNode *>(this));
          VariableNode *aux_var = datatree.AddVariable(symb_id, 0);
          neweqs.push_back(datatree.AddEqual(aux_var,
                                             datatree.AddMinus(argsubst,
                                                               argsubst->decreaseLeadsLags(1))));
          subst_table[this] = dynamic_cast<VariableNode *>(aux_var);
          return const_cast<VariableNode *>(subst_table[this]);
        }
    
      /* At this point, we know that this node (and its lagged/leaded brothers)
         must be substituted. We create the auxiliary variable and fill the
         substitution table for all those similar nodes, in an iteration going from
         leads to lags. */
      int last_index = 0;
      VariableNode *last_aux_var = nullptr;
      for (auto rit = it->second.rbegin(); rit != it->second.rend(); ++rit)
        {
          expr_t argsubst = dynamic_cast<UnaryOpNode *>(rit->second)->
            arg->substituteDiff(nodes, subst_table, neweqs);
          auto vn = dynamic_cast<VariableNode *>(argsubst);
          int symb_id;
          if (rit == it->second.rbegin())
            {
              if (vn)
                symb_id = datatree.symbol_table.addDiffAuxiliaryVar(argsubst->idx, rit->second, vn->symb_id, vn->lag);
              else
                symb_id = datatree.symbol_table.addDiffAuxiliaryVar(argsubst->idx, rit->second);
    
              // make originating aux var & equation
              last_index = rit->first;
              last_aux_var = datatree.AddVariable(symb_id, 0);
              //ORIG_AUX_DIFF = argsubst - argsubst(-1)
              neweqs.push_back(datatree.AddEqual(last_aux_var,
                                                 datatree.AddMinus(argsubst,
                                                                   argsubst->decreaseLeadsLags(1))));
              subst_table[rit->second] = dynamic_cast<VariableNode *>(last_aux_var);
            }
          else
            {
              // just add equation of form: AUX_DIFF = LAST_AUX_VAR(-1)
              VariableNode *new_aux_var = nullptr;
              for (int i = last_index; i > rit->first; i--)
                {
                  if (i == last_index)
                    symb_id = datatree.symbol_table.addDiffLagAuxiliaryVar(argsubst->idx, rit->second,
                                                                           last_aux_var->symb_id, last_aux_var->lag);
                  else
                    symb_id = datatree.symbol_table.addDiffLagAuxiliaryVar(new_aux_var->idx, rit->second,
                                                                           last_aux_var->symb_id, last_aux_var->lag);
    
                  new_aux_var = datatree.AddVariable(symb_id, 0);
                  neweqs.push_back(datatree.AddEqual(new_aux_var,
                                                     last_aux_var->decreaseLeadsLags(1)));
                  last_aux_var = new_aux_var;
                }
              subst_table[rit->second] = dynamic_cast<VariableNode *>(new_aux_var);
              last_index = rit->first;
            }
        }
      return const_cast<VariableNode *>(subst_table[this]);
    }
    
    expr_t
    UnaryOpNode::substituteUnaryOpNodes(const lag_equivalence_table_t &nodes, subst_table_t &subst_table, vector<BinaryOpNode *> &neweqs) const
    {
      if (auto sit = subst_table.find(this);
          sit != subst_table.end())
        return const_cast<VariableNode *>(sit->second);
    
      /* If the equivalence class of this node is not marked for substitution,
         then substitute recursively and return. */
      auto [lag_equiv_repr, index] = getLagEquivalenceClass();
      auto it = nodes.find(lag_equiv_repr);
      expr_t argsubst = arg->substituteUnaryOpNodes(nodes, subst_table, neweqs);
      if (it == nodes.end())
        return buildSimilarUnaryOpNode(argsubst, datatree);
    
      string unary_op;
      switch (op_code)
        {
        case UnaryOpcode::exp:
          unary_op = "exp";
          break;
        case UnaryOpcode::log:
          unary_op = "log";
          break;
        case UnaryOpcode::log10:
          unary_op = "log10";
          break;
        case UnaryOpcode::cos:
          unary_op = "cos";
          break;
        case UnaryOpcode::sin:
          unary_op = "sin";
          break;
        case UnaryOpcode::tan:
          unary_op = "tan";
          break;
        case UnaryOpcode::acos:
          unary_op = "acos";
          break;
        case UnaryOpcode::asin:
          unary_op = "asin";
          break;
        case UnaryOpcode::atan:
          unary_op = "atan";
          break;
        case UnaryOpcode::cosh:
          unary_op = "cosh";
          break;
        case UnaryOpcode::sinh:
          unary_op = "sinh";
          break;
        case UnaryOpcode::tanh:
          unary_op = "tanh";
          break;
        case UnaryOpcode::acosh:
          unary_op = "acosh";
          break;
        case UnaryOpcode::asinh:
          unary_op = "asinh";
          break;
        case UnaryOpcode::atanh:
          unary_op = "atanh";
          break;
        case UnaryOpcode::sqrt:
          unary_op = "sqrt";
          break;
        case UnaryOpcode::cbrt:
          unary_op = "cbrt";
          break;
        case UnaryOpcode::abs:
          unary_op = "abs";
          break;
        case UnaryOpcode::sign:
          unary_op = "sign";
          break;
        case UnaryOpcode::erf:
          unary_op = "erf";
          break;
        case UnaryOpcode::erfc:
          unary_op = "erfc";
          break;
        default:
          cerr << "UnaryOpNode::substituteUnaryOpNodes: Shouldn't arrive here" << endl;
          exit(EXIT_FAILURE);
        }
    
      /* At this point, we know that this node (and its lagged/leaded brothers)
         must be substituted. We create the auxiliary variable and fill the
         substitution table for all those similar nodes, in an iteration going from
         leads to lags. */
      int base_index = 0;
      VariableNode *aux_var = nullptr;
      for (auto rit = it->second.rbegin(); rit != it->second.rend(); ++rit)
        if (rit == it->second.rbegin())
          {
            /* Verify that we’re not operating on a node with leads, since the
               transformation does take into account the expectation operator. We only
               need to do this for the first iteration of the loop, because we’re
               going from leads to lags. */
            if (rit->second->maxLead() > 0)
              {
                cerr << "Cannot substitute unary operations that contain leads" << endl;
                exit(EXIT_FAILURE);
              }
    
            int symb_id;
            auto vn = dynamic_cast<VariableNode *>(argsubst);
            if (!vn)
              symb_id = datatree.symbol_table.addUnaryOpAuxiliaryVar(this->idx, dynamic_cast<UnaryOpNode *>(rit->second), unary_op);
            else
              symb_id = datatree.symbol_table.addUnaryOpAuxiliaryVar(this->idx, dynamic_cast<UnaryOpNode *>(rit->second), unary_op,
                                                                     vn->symb_id, vn->lag);
            aux_var = datatree.AddVariable(symb_id, 0);
            neweqs.push_back(datatree.AddEqual(aux_var,
                                               dynamic_cast<UnaryOpNode *>(rit->second)));
            subst_table[rit->second] = dynamic_cast<VariableNode *>(aux_var);
            base_index = rit->first;
          }
        else
          subst_table[rit->second] = dynamic_cast<VariableNode *>(aux_var->decreaseLeadsLags(base_index - rit->first));
    
      assert(subst_table.find(this) != subst_table.end());
    
      return const_cast<VariableNode *>(subst_table.at(this));
    }
    
    expr_t
    UnaryOpNode::substitutePacExpectation(const string &name, expr_t subexpr)
    {
      expr_t argsubst = arg->substitutePacExpectation(name, subexpr);
      return buildSimilarUnaryOpNode(argsubst, datatree);
    }
    
    expr_t
    UnaryOpNode::substitutePacTargetNonstationary(const string &name, expr_t subexpr)
    {
      expr_t argsubst = arg->substitutePacTargetNonstationary(name, subexpr);
      return buildSimilarUnaryOpNode(argsubst, datatree);
    }
    
    expr_t
    UnaryOpNode::decreaseLeadsLags(int n) const
    {
      expr_t argsubst = arg->decreaseLeadsLags(n);
      return buildSimilarUnaryOpNode(argsubst, datatree);
    }
    
    expr_t
    UnaryOpNode::decreaseLeadsLagsPredeterminedVariables() const
    {
      expr_t argsubst = arg->decreaseLeadsLagsPredeterminedVariables();
      return buildSimilarUnaryOpNode(argsubst, datatree);
    }
    
    expr_t
    UnaryOpNode::substituteEndoLeadGreaterThanTwo(subst_table_t &subst_table, vector<BinaryOpNode *> &neweqs, bool deterministic_model) const
    {
      if (op_code == UnaryOpcode::uminus || deterministic_model)
        {
          expr_t argsubst = arg->substituteEndoLeadGreaterThanTwo(subst_table, neweqs, deterministic_model);
          return buildSimilarUnaryOpNode(argsubst, datatree);
        }
      else
        {
          if (maxEndoLead() >= 2)
            return createEndoLeadAuxiliaryVarForMyself(subst_table, neweqs);
          else
            return const_cast<UnaryOpNode *>(this);
        }
    }
    
    expr_t
    UnaryOpNode::substituteEndoLagGreaterThanTwo(subst_table_t &subst_table, vector<BinaryOpNode *> &neweqs) const
    {
      expr_t argsubst = arg->substituteEndoLagGreaterThanTwo(subst_table, neweqs);
      return buildSimilarUnaryOpNode(argsubst, datatree);
    }
    
    expr_t
    UnaryOpNode::substituteExoLead(subst_table_t &subst_table, vector<BinaryOpNode *> &neweqs, bool deterministic_model) const
    {
      if (op_code == UnaryOpcode::uminus || deterministic_model)
        {
          expr_t argsubst = arg->substituteExoLead(subst_table, neweqs, deterministic_model);
          return buildSimilarUnaryOpNode(argsubst, datatree);
        }
      else
        {
          if (maxExoLead() >= 1)
            return createExoLeadAuxiliaryVarForMyself(subst_table, neweqs);
          else
            return const_cast<UnaryOpNode *>(this);
        }
    }
    
    expr_t
    UnaryOpNode::substituteExoLag(subst_table_t &subst_table, vector<BinaryOpNode *> &neweqs) const
    {
      expr_t argsubst = arg->substituteExoLag(subst_table, neweqs);
      return buildSimilarUnaryOpNode(argsubst, datatree);
    }
    
    expr_t
    UnaryOpNode::substituteExpectation(subst_table_t &subst_table, vector<BinaryOpNode *> &neweqs, bool partial_information_model) const
    {
      if (op_code == UnaryOpcode::expectation)
        {
          if (auto it = subst_table.find(const_cast<UnaryOpNode *>(this)); it != subst_table.end())
            return const_cast<VariableNode *>(it->second);
    
          //Arriving here, we need to create an auxiliary variable for this Expectation Operator:
          //AUX_EXPECT_(LEAD/LAG)_(period)_(arg.idx) OR
          //AUX_EXPECT_(info_set_name)_(arg.idx)
          int symb_id = datatree.symbol_table.addExpectationAuxiliaryVar(expectation_information_set, arg->idx, const_cast<UnaryOpNode *>(this));
          expr_t newAuxE = datatree.AddVariable(symb_id, 0);
    
          if (partial_information_model && expectation_information_set == 0)
            if (!dynamic_cast<VariableNode *>(arg))
              {
                cerr << "ERROR: In Partial Information models, EXPECTATION(0)(X) "
                     << "can only be used when X is a single variable." << endl;
                exit(EXIT_FAILURE);
              }
    
          //take care of any nested expectation operators by calling arg->substituteExpectation(.), then decreaseLeadsLags for this UnaryOpcode::expectation operator
          //arg(lag-period) (holds entire subtree of arg(lag-period)
          expr_t substexpr = (arg->substituteExpectation(subst_table, neweqs, partial_information_model))->decreaseLeadsLags(expectation_information_set);
          assert(substexpr);
          neweqs.push_back(datatree.AddEqual(newAuxE, substexpr)); //AUXE_period_arg.idx = arg(lag-period)
          newAuxE = datatree.AddVariable(symb_id, expectation_information_set);
    
          assert(dynamic_cast<VariableNode *>(newAuxE));
          subst_table[this] = dynamic_cast<VariableNode *>(newAuxE);
          return newAuxE;
        }
      else
        {
          expr_t argsubst = arg->substituteExpectation(subst_table, neweqs, partial_information_model);
          return buildSimilarUnaryOpNode(argsubst, datatree);
        }
    }
    
    expr_t
    UnaryOpNode::differentiateForwardVars(const vector<string> &subset, subst_table_t &subst_table, vector<BinaryOpNode *> &neweqs) const
    {
      expr_t argsubst = arg->differentiateForwardVars(subset, subst_table, neweqs);
      return buildSimilarUnaryOpNode(argsubst, datatree);
    }
    
    bool
    UnaryOpNode::isNumConstNodeEqualTo(double value) const
    {
      return false;
    }
    
    bool
    UnaryOpNode::isVariableNodeEqualTo(SymbolType type_arg, int variable_id, int lag_arg) const
    {
      return false;
    }
    
    bool
    UnaryOpNode::containsPacExpectation(const string &pac_model_name) const
    {
      return arg->containsPacExpectation(pac_model_name);
    }
    
    bool
    UnaryOpNode::containsPacTargetNonstationary(const string &pac_model_name) const
    {
      return arg->containsPacTargetNonstationary(pac_model_name);
    }
    
    expr_t
    UnaryOpNode::replaceTrendVar() const
    {
      expr_t argsubst = arg->replaceTrendVar();
      return buildSimilarUnaryOpNode(argsubst, datatree);
    }
    
    expr_t
    UnaryOpNode::detrend(int symb_id, bool log_trend, expr_t trend) const
    {
      expr_t argsubst = arg->detrend(symb_id, log_trend, trend);
      return buildSimilarUnaryOpNode(argsubst, datatree);
    }
    
    expr_t
    UnaryOpNode::removeTrendLeadLag(const map<int, expr_t> &trend_symbols_map) const
    {
      expr_t argsubst = arg->removeTrendLeadLag(trend_symbols_map);
      return buildSimilarUnaryOpNode(argsubst, datatree);
    }
    
    bool
    UnaryOpNode::isInStaticForm() const
    {
      if (op_code == UnaryOpcode::steadyState || op_code == UnaryOpcode::steadyStateParamDeriv
          || op_code == UnaryOpcode::steadyStateParam2ndDeriv
          || op_code == UnaryOpcode::expectation)
        return false;
      else
        return arg->isInStaticForm();
    }
    
    bool
    UnaryOpNode::isParamTimesEndogExpr() const
    {
      return arg->isParamTimesEndogExpr();
    }
    
    expr_t
    UnaryOpNode::substituteStaticAuxiliaryVariable() const
    {
      if (op_code == UnaryOpcode::diff)
        return datatree.Zero;
    
      expr_t argsubst = arg->substituteStaticAuxiliaryVariable();
      if (op_code == UnaryOpcode::expectation)
        return argsubst;
      else
        return buildSimilarUnaryOpNode(argsubst, datatree);
    }
    
    expr_t
    UnaryOpNode::replaceVarsInEquation(map<VariableNode *, NumConstNode *> &table) const
    {
      expr_t argsubst = arg->replaceVarsInEquation(table);
      return buildSimilarUnaryOpNode(argsubst, datatree);
    }
    
    BinaryOpNode::BinaryOpNode(DataTree &datatree_arg, int idx_arg, const expr_t arg1_arg,
                               BinaryOpcode op_code_arg, const expr_t arg2_arg, int powerDerivOrder_arg) :
      ExprNode{datatree_arg, idx_arg},
      arg1{arg1_arg},
      arg2{arg2_arg},
      op_code{op_code_arg},
      powerDerivOrder{powerDerivOrder_arg}
    {
      assert(powerDerivOrder >= 0);
    }
    
    void
    BinaryOpNode::prepareForDerivation()
    {
      if (preparedForDerivation)
        return;
    
      preparedForDerivation = true;
    
      arg1->prepareForDerivation();
      arg2->prepareForDerivation();
    
      // Non-null derivatives are the union of those of the arguments
      // Compute set union of arg1->non_null_derivatives and arg2->non_null_derivatives
      set_union(arg1->non_null_derivatives.begin(),
                arg1->non_null_derivatives.end(),
                arg2->non_null_derivatives.begin(),
                arg2->non_null_derivatives.end(),
                inserter(non_null_derivatives, non_null_derivatives.begin()));
    }
    
    expr_t
    BinaryOpNode::getNonZeroPartofEquation() const
    {
      assert(arg1 == datatree.Zero || arg2 == datatree.Zero);
      if (arg1 == datatree.Zero)
        return arg2;
      return arg1;
    }
    
    expr_t
    BinaryOpNode::composeDerivatives(expr_t darg1, expr_t darg2)
    {
      expr_t t11, t12, t13, t14, t15;
    
      switch (op_code)
        {
        case BinaryOpcode::plus:
          return datatree.AddPlus(darg1, darg2);
        case BinaryOpcode::minus:
        case BinaryOpcode::equal:
          return datatree.AddMinus(darg1, darg2);
        case BinaryOpcode::times:
          t11 = datatree.AddTimes(darg1, arg2);
          t12 = datatree.AddTimes(darg2, arg1);
          return datatree.AddPlus(t11, t12);
        case BinaryOpcode::divide:
          if (darg2 != datatree.Zero)
            {
              t11 = datatree.AddTimes(darg1, arg2);
              t12 = datatree.AddTimes(darg2, arg1);
              t13 = datatree.AddMinus(t11, t12);
              t14 = datatree.AddTimes(arg2, arg2);
              return datatree.AddDivide(t13, t14);
            }
          else
            return datatree.AddDivide(darg1, arg2);
        case BinaryOpcode::less:
        case BinaryOpcode::greater:
        case BinaryOpcode::lessEqual:
        case BinaryOpcode::greaterEqual:
        case BinaryOpcode::equalEqual:
        case BinaryOpcode::different:
          return datatree.Zero;
        case BinaryOpcode::power:
          if (darg2 == datatree.Zero)
            if (darg1 == datatree.Zero)
              return datatree.Zero;
            else
              if (dynamic_cast<NumConstNode *>(arg2))
                {
                  t11 = datatree.AddMinus(arg2, datatree.One);
                  t12 = datatree.AddPower(arg1, t11);
                  t13 = datatree.AddTimes(arg2, t12);
                  return datatree.AddTimes(darg1, t13);
                }
              else
                return datatree.AddTimes(darg1, datatree.AddPowerDeriv(arg1, arg2, powerDerivOrder + 1));
          else
            {
              t11 = datatree.AddLog(arg1);
              t12 = datatree.AddTimes(darg2, t11);
              t13 = datatree.AddTimes(darg1, arg2);
              t14 = datatree.AddDivide(t13, arg1);
              t15 = datatree.AddPlus(t12, t14);
              return datatree.AddTimes(t15, this);
            }
        case BinaryOpcode::powerDeriv:
          if (darg2 == datatree.Zero)
            return datatree.AddTimes(darg1, datatree.AddPowerDeriv(arg1, arg2, powerDerivOrder + 1));
          else
            {
              t11 = datatree.AddTimes(darg2, datatree.AddLog(arg1));
              t12 = datatree.AddMinus(arg2, datatree.AddPossiblyNegativeConstant(powerDerivOrder));
              t13 = datatree.AddTimes(darg1, t12);
              t14 = datatree.AddDivide(t13, arg1);
              t15 = datatree.AddPlus(t11, t14);
              expr_t f = datatree.AddPower(arg1, t12);
              expr_t first_part = datatree.AddTimes(f, t15);
    
              for (int i = 0; i < powerDerivOrder; i++)
                first_part = datatree.AddTimes(first_part, datatree.AddMinus(arg2, datatree.AddPossiblyNegativeConstant(i)));
    
              t13 = datatree.Zero;
              for (int i = 0; i < powerDerivOrder; i++)
                {
                  t11 = datatree.One;
                  for (int j = 0; j < powerDerivOrder; j++)
                    if (i != j)
                      {
                        t12 = datatree.AddMinus(arg2, datatree.AddPossiblyNegativeConstant(j));
                        t11 = datatree.AddTimes(t11, t12);
                      }
                  t13 = datatree.AddPlus(t13, t11);
                }
              t13 = datatree.AddTimes(darg2, t13);
              t14 = datatree.AddTimes(f, t13);
              return datatree.AddPlus(first_part, t14);
            }
        case BinaryOpcode::max:
          t11 = datatree.AddGreater(arg1, arg2);
          t12 = datatree.AddTimes(t11, darg1);
          t13 = datatree.AddMinus(datatree.One, t11);
          t14 = datatree.AddTimes(t13, darg2);
          return datatree.AddPlus(t14, t12);
        case BinaryOpcode::min:
          t11 = datatree.AddGreater(arg2, arg1);
          t12 = datatree.AddTimes(t11, darg1);
          t13 = datatree.AddMinus(datatree.One, t11);
          t14 = datatree.AddTimes(t13, darg2);
          return datatree.AddPlus(t14, t12);
        }
      // Suppress GCC warning
      exit(EXIT_FAILURE);
    }
    
    expr_t
    BinaryOpNode::unpackPowerDeriv() const
    {
      if (op_code != BinaryOpcode::powerDeriv)
        return const_cast<BinaryOpNode *>(this);
    
      expr_t front = datatree.One;
      for (int i = 0; i < powerDerivOrder; i++)
        front = datatree.AddTimes(front,
                                  datatree.AddMinus(arg2,
                                                    datatree.AddPossiblyNegativeConstant(i)));
      expr_t tmp = datatree.AddPower(arg1,
                                     datatree.AddMinus(arg2,
                                                       datatree.AddPossiblyNegativeConstant(powerDerivOrder)));
      return datatree.AddTimes(front, tmp);
    }
    
    expr_t
    BinaryOpNode::computeDerivative(int deriv_id)
    {
      expr_t darg1 = arg1->getDerivative(deriv_id);
      expr_t darg2 = arg2->getDerivative(deriv_id);
      return composeDerivatives(darg1, darg2);
    }
    
    int
    BinaryOpNode::precedence(ExprNodeOutputType output_type, const temporary_terms_t &temporary_terms) const
    {
      // A temporary term behaves as a variable
      if (temporary_terms.find(const_cast<BinaryOpNode *>(this)) != temporary_terms.end())
        return 100;
    
      switch (op_code)
        {
        case BinaryOpcode::equal:
          return 0;
        case BinaryOpcode::equalEqual:
        case BinaryOpcode::different:
          return 1;
        case BinaryOpcode::lessEqual:
        case BinaryOpcode::greaterEqual:
        case BinaryOpcode::less:
        case BinaryOpcode::greater:
          return 2;
        case BinaryOpcode::plus:
        case BinaryOpcode::minus:
          return 3;
        case BinaryOpcode::times:
        case BinaryOpcode::divide:
          return 4;
        case BinaryOpcode::power:
        case BinaryOpcode::powerDeriv:
          if (isCOutput(output_type))
            // In C, power operator is of the form pow(a, b)
            return 100;
          else
            return 5;
        case BinaryOpcode::min:
        case BinaryOpcode::max:
          return 100;
        }
      // Suppress GCC warning
      exit(EXIT_FAILURE);
    }
    
    int
    BinaryOpNode::precedenceJson(const temporary_terms_t &temporary_terms) const
    {
      // A temporary term behaves as a variable
      if (temporary_terms.find(const_cast<BinaryOpNode *>(this)) != temporary_terms.end())
        return 100;
    
      switch (op_code)
        {
        case BinaryOpcode::equal:
          return 0;
        case BinaryOpcode::equalEqual:
        case BinaryOpcode::different:
          return 1;
        case BinaryOpcode::lessEqual:
        case BinaryOpcode::greaterEqual:
        case BinaryOpcode::less:
        case BinaryOpcode::greater:
          return 2;
        case BinaryOpcode::plus:
        case BinaryOpcode::minus:
          return 3;
        case BinaryOpcode::times:
        case BinaryOpcode::divide:
          return 4;
        case BinaryOpcode::power:
        case BinaryOpcode::powerDeriv:
          return 5;
        case BinaryOpcode::min:
        case BinaryOpcode::max:
          return 100;
        }
      // Suppress GCC warning
      exit(EXIT_FAILURE);
    }
    
    int
    BinaryOpNode::cost(const map<pair<int, int>, temporary_terms_t> &temp_terms_map, bool is_matlab) const
    {
      // For a temporary term, the cost is null
      for (const auto &it : temp_terms_map)
        if (it.second.find(const_cast<BinaryOpNode *>(this)) != it.second.end())
          return 0;
    
      int arg_cost = arg1->cost(temp_terms_map, is_matlab) + arg2->cost(temp_terms_map, is_matlab);
    
      return cost(arg_cost, is_matlab);
    }
    
    int
    BinaryOpNode::cost(const vector<vector<temporary_terms_t>> &blocks_temporary_terms, bool is_matlab) const
    {
      // For a temporary term, the cost is null
      for (const auto &blk_tt : blocks_temporary_terms)
        for (const auto &eq_tt : blk_tt)
          if (eq_tt.find(const_cast<BinaryOpNode *>(this)) != eq_tt.end())
            return 0;
    
      int arg_cost = arg1->cost(blocks_temporary_terms, is_matlab) + arg2->cost(blocks_temporary_terms, is_matlab);
    
      return cost(arg_cost, is_matlab);
    }
    
    int
    BinaryOpNode::cost(int cost, bool is_matlab) const
    {
      if (is_matlab)
        // Cost for Matlab files
        switch (op_code)
          {
          case BinaryOpcode::less:
          case BinaryOpcode::greater:
          case BinaryOpcode::lessEqual:
          case BinaryOpcode::greaterEqual:
          case BinaryOpcode::equalEqual:
          case BinaryOpcode::different:
            return cost + 60;
          case BinaryOpcode::plus:
          case BinaryOpcode::minus:
          case BinaryOpcode::times:
            return cost + 90;
          case BinaryOpcode::max:
          case BinaryOpcode::min:
            return cost + 110;
          case BinaryOpcode::divide:
            return cost + 990;
          case BinaryOpcode::power:
          case BinaryOpcode::powerDeriv:
            return cost + (min_cost_matlab/2+1);
          case BinaryOpcode::equal:
            return cost;
          }
      else
        // Cost for C files
        switch (op_code)
          {
          case BinaryOpcode::less:
          case BinaryOpcode::greater:
          case BinaryOpcode::lessEqual:
          case BinaryOpcode::greaterEqual:
          case BinaryOpcode::equalEqual:
          case BinaryOpcode::different:
            return cost + 2;
          case BinaryOpcode::plus:
          case BinaryOpcode::minus:
          case BinaryOpcode::times:
            return cost + 4;
          case BinaryOpcode::max:
          case BinaryOpcode::min:
            return cost + 5;
          case BinaryOpcode::divide:
            return cost + 15;
          case BinaryOpcode::power:
            return cost + 520;
          case BinaryOpcode::powerDeriv:
            return cost + (min_cost_c/2+1);
          case BinaryOpcode::equal:
            return cost;
          }
      // Suppress GCC warning
      exit(EXIT_FAILURE);
    }
    
    void
    BinaryOpNode::computeTemporaryTerms(const pair<int, int> &derivOrder,
                                        map<pair<int, int>, temporary_terms_t> &temp_terms_map,
                                        map<expr_t, pair<int, pair<int, int>>> &reference_count,
                                        bool is_matlab) const
    {
      expr_t this2 = const_cast<BinaryOpNode *>(this);
      if (auto it = reference_count.find(this2);
          it == reference_count.end())
        {
          // If this node has never been encountered, set its ref count to one,
          //  and travel through its children
          reference_count[this2] = { 1, derivOrder };
          arg1->computeTemporaryTerms(derivOrder, temp_terms_map, reference_count, is_matlab);
          arg2->computeTemporaryTerms(derivOrder, temp_terms_map, reference_count, is_matlab);
        }
      else
        {
          /* If the node has already been encountered, increment its ref count
             and declare it as a temporary term if it is too costly (except if it is
             an equal node: we don't want them as temporary terms) */
          auto &[nref, min_order] = it->second;
          nref++;
          if (nref * cost(temp_terms_map, is_matlab) > min_cost(is_matlab)
              && op_code != BinaryOpcode::equal)
            temp_terms_map[min_order].insert(this2);
        }
    }
    
    void
    BinaryOpNode::computeBlockTemporaryTerms(int blk, int eq, vector<vector<temporary_terms_t>> &blocks_temporary_terms,
                                             map<expr_t, tuple<int, int, int>> &reference_count) const
    {
      expr_t this2 = const_cast<BinaryOpNode *>(this);
      if (auto it = reference_count.find(this2);
          it == reference_count.end())
        {
          reference_count[this2] = { 1, blk, eq };
          arg1->computeBlockTemporaryTerms(blk, eq, blocks_temporary_terms, reference_count);
          arg2->computeBlockTemporaryTerms(blk, eq, blocks_temporary_terms, reference_count);
        }
      else
        {
          auto &[nref, first_blk, first_eq] = it->second;
          nref++;
          if (nref * cost(blocks_temporary_terms, false) > min_cost_c
              && op_code != BinaryOpcode::equal)
            blocks_temporary_terms[first_blk][first_eq].insert(this2);
        }
    }
    
    double
    BinaryOpNode::eval_opcode(double v1, BinaryOpcode op_code, double v2, int derivOrder) noexcept(false)
    {
      switch (op_code)
        {
        case BinaryOpcode::plus:
          return v1 + v2;
        case BinaryOpcode::minus:
          return v1 - v2;
        case BinaryOpcode::times:
          return v1 * v2;
        case BinaryOpcode::divide:
          return v1 / v2;
        case BinaryOpcode::power:
          return pow(v1, v2);
        case BinaryOpcode::powerDeriv:
          if (fabs(v1) < near_zero && v2 > 0
              && derivOrder > v2
              && fabs(v2-nearbyint(v2)) < near_zero)
            return 0.0;
          else
            {
              double dxp = pow(v1, v2-derivOrder);
              for (int i = 0; i < derivOrder; i++)
                dxp *= v2--;
              return dxp;
            }
        case BinaryOpcode::max:
          if (v1 < v2)
            return v2;
          else
            return v1;
        case BinaryOpcode::min:
          if (v1 > v2)
            return v2;
          else
            return v1;
        case BinaryOpcode::less:
          return v1 < v2;
        case BinaryOpcode::greater:
          return v1 > v2;
        case BinaryOpcode::lessEqual:
          return v1 <= v2;
        case BinaryOpcode::greaterEqual:
          return v1 >= v2;
        case BinaryOpcode::equalEqual:
          return v1 == v2;
        case BinaryOpcode::different:
          return v1 != v2;
        case BinaryOpcode::equal:
          throw EvalException();
        }
      // Suppress GCC warning
      exit(EXIT_FAILURE);
    }
    
    double
    BinaryOpNode::eval(const eval_context_t &eval_context) const noexcept(false)
    {
      double v1 = arg1->eval(eval_context);
      double v2 = arg2->eval(eval_context);
      return eval_opcode(v1, op_code, v2, powerDerivOrder);
    }
    
    void
    BinaryOpNode::compile(ostream &CompileCode, unsigned int &instruction_number,
                          bool lhs_rhs, const temporary_terms_t &temporary_terms,
                          const temporary_terms_idxs_t &temporary_terms_idxs, bool dynamic, bool steady_dynamic,
                          const deriv_node_temp_terms_t &tef_terms) const
    {
      // If current node is a temporary term
      if (auto this2 = const_cast<BinaryOpNode *>(this);
          temporary_terms.find(this2) != temporary_terms.end())
        {
          if (dynamic)
            {
              FLDT_ fldt(temporary_terms_idxs.at(this2));
              fldt.write(CompileCode, instruction_number);
            }
          else
            {
              FLDST_ fldst(temporary_terms_idxs.at(this2));
              fldst.write(CompileCode, instruction_number);
            }
          return;
        }
      if (op_code == BinaryOpcode::powerDeriv)
        {
          FLDC_ fldc(powerDerivOrder);
          fldc.write(CompileCode, instruction_number);
        }
      arg1->compile(CompileCode, instruction_number, lhs_rhs, temporary_terms, temporary_terms_idxs, dynamic, steady_dynamic, tef_terms);
      arg2->compile(CompileCode, instruction_number, lhs_rhs, temporary_terms, temporary_terms_idxs, dynamic, steady_dynamic, tef_terms);
      FBINARY_ fbinary{static_cast<int>(op_code)};
      fbinary.write(CompileCode, instruction_number);
    }
    
    bool
    BinaryOpNode::containsExternalFunction() const
    {
      return arg1->containsExternalFunction()
        || arg2->containsExternalFunction();
    }
    
    void
    BinaryOpNode::writeJsonAST(ostream &output) const
    {
      output << R"({"node_type" : "BinaryOpNode",)"
             << R"( "op" : ")";
      switch (op_code)
        {
        case BinaryOpcode::plus:
          output << "+";
          break;
        case BinaryOpcode::minus:
          output << "-";
          break;
        case BinaryOpcode::times:
          output << "*";
          break;
        case BinaryOpcode::divide:
          output << "/";
          break;
        case BinaryOpcode::power:
          output << "^";
          break;
        case BinaryOpcode::less:
          output << "<";
          break;
        case BinaryOpcode::greater:
          output << ">";
          break;
        case BinaryOpcode::lessEqual:
          output << "<=";
          break;
        case BinaryOpcode::greaterEqual:
          output << ">=";
          break;
        case BinaryOpcode::equalEqual:
          output << "==";
          break;
        case BinaryOpcode::different:
          output << "!=";
          break;
        case BinaryOpcode::equal:
          output << "=";
          break;
        case BinaryOpcode::max:
          output << "max";
          break;
        case BinaryOpcode::min:
          output << "min";
          break;
        case BinaryOpcode::powerDeriv:
          output << "power_deriv";
          break;
        }
      output << R"(", "arg1" : )";
      arg1->writeJsonAST(output);
      output << R"(, "arg2" : )";
      arg2->writeJsonAST(output);
      output << "}";
    }
    
    void
    BinaryOpNode::writeJsonOutput(ostream &output,
                                  const temporary_terms_t &temporary_terms,
                                  const deriv_node_temp_terms_t &tef_terms,
                                  bool isdynamic) const
    {
      // If current node is a temporary term
      if (temporary_terms.find(const_cast<BinaryOpNode *>(this)) != temporary_terms.end())
        {
          output << "T" << idx;
          return;
        }
    
      if (op_code == BinaryOpcode::max || op_code == BinaryOpcode::min)
        {
          switch (op_code)
            {
            case BinaryOpcode::max:
              output << "max(";
              break;
            case BinaryOpcode::min:
              output << "min(";
              break;
            default:
              ;
            }
          arg1->writeJsonOutput(output, temporary_terms, tef_terms, isdynamic);
          output << ",";
          arg2->writeJsonOutput(output, temporary_terms, tef_terms, isdynamic);
          output << ")";
          return;
        }
    
      if (op_code == BinaryOpcode::powerDeriv)
        {
          output << "get_power_deriv(";
          arg1->writeJsonOutput(output, temporary_terms, tef_terms, isdynamic);
          output << ",";
          arg2->writeJsonOutput(output, temporary_terms, tef_terms, isdynamic);
          output << "," << powerDerivOrder << ")";
          return;
        }
    
      int prec = precedenceJson(temporary_terms);
    
      bool close_parenthesis = false;
    
      // If left argument has a lower precedence, or if current and left argument are both power operators,
      // add parenthesis around left argument
      if (auto barg1 = dynamic_cast<BinaryOpNode *>(arg1);
          arg1->precedenceJson(temporary_terms) < prec
          || (op_code == BinaryOpcode::power && barg1 && barg1->op_code == BinaryOpcode::power))
        {
          output << "(";
          close_parenthesis = true;
        }
    
      // Write left argument
      arg1->writeJsonOutput(output, temporary_terms, tef_terms, isdynamic);
    
      if (close_parenthesis)
        output << ")";
    
      // Write current operator symbol
      switch (op_code)
        {
        case BinaryOpcode::plus:
          output << "+";
          break;
        case BinaryOpcode::minus:
          output << "-";
          break;
        case BinaryOpcode::times:
          output << "*";
          break;
        case BinaryOpcode::divide:
          output << "/";
          break;
        case BinaryOpcode::power:
          output << "^";
          break;
        case BinaryOpcode::less:
          output << "<";
          break;
        case BinaryOpcode::greater:
          output << ">";
          break;
        case BinaryOpcode::lessEqual:
          output << "<=";
          break;
        case BinaryOpcode::greaterEqual:
          output << ">=";
          break;
        case BinaryOpcode::equalEqual:
          output << "==";
          break;
        case BinaryOpcode::different:
          output << "!=";
          break;
        case BinaryOpcode::equal:
          output << "=";
          break;
        default:
          ;
        }
    
      close_parenthesis = false;
    
      /* Add parenthesis around right argument if:
         - its precedence is lower than those of the current node
         - it is a power operator and current operator is also a power operator
         - it is a minus operator with same precedence than current operator
         - it is a divide operator with same precedence than current operator */
      auto barg2 = dynamic_cast<BinaryOpNode *>(arg2);
      if (int arg2_prec = arg2->precedenceJson(temporary_terms); arg2_prec < prec
          || (op_code == BinaryOpcode::power && barg2 && barg2->op_code == BinaryOpcode::power)
          || (op_code == BinaryOpcode::minus && arg2_prec == prec)
          || (op_code == BinaryOpcode::divide && arg2_prec == prec))
        {
          output << "(";
          close_parenthesis = true;
        }
    
      // Write right argument
      arg2->writeJsonOutput(output, temporary_terms, tef_terms, isdynamic);
    
      if (close_parenthesis)
        output << ")";
    }
    
    void
    BinaryOpNode::writeOutput(ostream &output, ExprNodeOutputType output_type,
                              const temporary_terms_t &temporary_terms,
                              const temporary_terms_idxs_t &temporary_terms_idxs,
                              const deriv_node_temp_terms_t &tef_terms) const
    {
      if (checkIfTemporaryTermThenWrite(output, output_type, temporary_terms, temporary_terms_idxs))
        return;
    
      // Treat derivative of Power
      if (op_code == BinaryOpcode::powerDeriv)
        {
          if (isLatexOutput(output_type))
            unpackPowerDeriv()->writeOutput(output, output_type, temporary_terms, temporary_terms_idxs, tef_terms);
          else
            {
              if (output_type == ExprNodeOutputType::juliaStaticModel || output_type == ExprNodeOutputType::juliaDynamicModel)
                output << "get_power_deriv(";
              else
                output << "getPowerDeriv(";
              arg1->writeOutput(output, output_type, temporary_terms, temporary_terms_idxs, tef_terms);
              output << ",";
              arg2->writeOutput(output, output_type, temporary_terms, temporary_terms_idxs, tef_terms);
              output << "," << powerDerivOrder << ")";
            }
          return;
        }
    
      // Treat special case of power operator in C, and case of max and min operators
      if ((op_code == BinaryOpcode::power && isCOutput(output_type)) || op_code == BinaryOpcode::max || op_code == BinaryOpcode::min)
        {
          switch (op_code)
            {
            case BinaryOpcode::power:
              output << "pow(";
              break;
            case BinaryOpcode::max:
              if (isCOutput(output_type))
                output << "fmax(";
              else
                output << "max(";
              break;
            case BinaryOpcode::min:
              if (isCOutput(output_type))
                output << "fmin(";
              else
                output << "min(";
              break;
            default:
              ;
            }
          arg1->writeOutput(output, output_type, temporary_terms, temporary_terms_idxs, tef_terms);
          output << ",";
          arg2->writeOutput(output, output_type, temporary_terms, temporary_terms_idxs, tef_terms);
          output << ")";
          return;
        }
    
      int prec = precedence(output_type, temporary_terms);
    
      bool close_parenthesis = false;
    
      if (isLatexOutput(output_type) && op_code == BinaryOpcode::divide)
        output << R"(\frac{)";
      else
        {
          // If left argument has a lower precedence, or if current and left argument are both power operators, add parenthesis around left argument
          auto barg1 = dynamic_cast<BinaryOpNode *>(arg1);
          if (arg1->precedence(output_type, temporary_terms) < prec
              || (op_code == BinaryOpcode::power && barg1 != nullptr && barg1->op_code == BinaryOpcode::power))
            {
              output << LEFT_PAR(output_type);
              close_parenthesis = true;
            }
        }
    
      // Write left argument
      arg1->writeOutput(output, output_type, temporary_terms, temporary_terms_idxs, tef_terms);
    
      if (close_parenthesis)
        output << RIGHT_PAR(output_type);
    
      if (isLatexOutput(output_type) && op_code == BinaryOpcode::divide)
        output << "}";
    
      // Write current operator symbol
      switch (op_code)
        {
        case BinaryOpcode::plus:
          output << "+";
          break;
        case BinaryOpcode::minus:
          output << "-";
          break;
        case BinaryOpcode::times:
          if (isLatexOutput(output_type))
            output << R"(\, )";
          else if (output_type == ExprNodeOutputType::occbinDifferenceFile)
            output << ".*"; // This file operates on vectors, see dynare#1826
          else
            output << "*";
          break;
        case BinaryOpcode::divide:
          if (!isLatexOutput(output_type))
            {
              if (output_type == ExprNodeOutputType::occbinDifferenceFile)
                output << "./"; // This file operates on vectors, see dynare#1826
              else
                output << "/";
            }
          break;
        case BinaryOpcode::power:
          if (output_type == ExprNodeOutputType::occbinDifferenceFile)
            output << ".^"; // This file operates on vectors, see dynare#1826
          else
            output << "^";
          break;
        case BinaryOpcode::less:
          output << "<";
          break;
        case BinaryOpcode::greater:
          output << ">";
          break;
        case BinaryOpcode::lessEqual:
          if (isLatexOutput(output_type))
            output << R"(\leq )";
          else
            output << "<=";
          break;
        case BinaryOpcode::greaterEqual:
          if (isLatexOutput(output_type))
            output << R"(\geq )";
          else
            output << ">=";
          break;
        case BinaryOpcode::equalEqual:
          output << "==";
          break;
        case BinaryOpcode::different:
          if (isMatlabOutput(output_type))
            output << "~=";
          else
            {
              if (isCOutput(output_type) || isJuliaOutput(output_type))
                output << "!=";
              else
                output << R"(\neq )";
            }
          break;
        case BinaryOpcode::equal:
          output << "=";
          break;
        default:
          ;
        }
    
      close_parenthesis = false;
    
      if (isLatexOutput(output_type) && (op_code == BinaryOpcode::power || op_code == BinaryOpcode::divide))
        output << "{";
      else
        {
          /* Add parenthesis around right argument if:
             - its precedence is lower than those of the current node
             - it is a power operator and current operator is also a power operator
             - it is a minus operator with same precedence than current operator
             - it is a divide operator with same precedence than current operator */
          auto barg2 = dynamic_cast<BinaryOpNode *>(arg2);
          if (int arg2_prec = arg2->precedence(output_type, temporary_terms); arg2_prec < prec
              || (op_code == BinaryOpcode::power && barg2 && barg2->op_code == BinaryOpcode::power && !isLatexOutput(output_type))
              || (op_code == BinaryOpcode::minus && arg2_prec == prec)
              || (op_code == BinaryOpcode::divide && arg2_prec == prec && !isLatexOutput(output_type)))
            {
              output << LEFT_PAR(output_type);
              close_parenthesis = true;
            }
        }
    
      // Write right argument
      arg2->writeOutput(output, output_type, temporary_terms, temporary_terms_idxs, tef_terms);
    
      if (isLatexOutput(output_type) && (op_code == BinaryOpcode::power || op_code == BinaryOpcode::divide))
        output << "}";
    
      if (close_parenthesis)
        output << RIGHT_PAR(output_type);
    }
    
    void
    BinaryOpNode::writeExternalFunctionOutput(ostream &output, ExprNodeOutputType output_type,
                                              const temporary_terms_t &temporary_terms,
                                              const temporary_terms_idxs_t &temporary_terms_idxs,
                                              deriv_node_temp_terms_t &tef_terms) const
    {
      arg1->writeExternalFunctionOutput(output, output_type, temporary_terms, temporary_terms_idxs, tef_terms);
      arg2->writeExternalFunctionOutput(output, output_type, temporary_terms, temporary_terms_idxs, tef_terms);
    }
    
    void
    BinaryOpNode::writeJsonExternalFunctionOutput(vector<string> &efout,
                                                  const temporary_terms_t &temporary_terms,
                                                  deriv_node_temp_terms_t &tef_terms,
                                                  bool isdynamic) const
    {
      arg1->writeJsonExternalFunctionOutput(efout, temporary_terms, tef_terms, isdynamic);
      arg2->writeJsonExternalFunctionOutput(efout, temporary_terms, tef_terms, isdynamic);
    }
    
    void
    BinaryOpNode::compileExternalFunctionOutput(ostream &CompileCode, unsigned int &instruction_number,
                                                bool lhs_rhs, const temporary_terms_t &temporary_terms,
                                                const temporary_terms_idxs_t &temporary_terms_idxs, bool dynamic, bool steady_dynamic,
                                                deriv_node_temp_terms_t &tef_terms) const
    {
      arg1->compileExternalFunctionOutput(CompileCode, instruction_number, lhs_rhs, temporary_terms,
                                          temporary_terms_idxs, dynamic, steady_dynamic, tef_terms);
      arg2->compileExternalFunctionOutput(CompileCode, instruction_number, lhs_rhs, temporary_terms,
                                          temporary_terms_idxs, dynamic, steady_dynamic, tef_terms);
    }
    
    int
    BinaryOpNode::VarMaxLag(const set<expr_t> &lhs_lag_equiv) const
    {
      return max(arg1->VarMaxLag(lhs_lag_equiv),
                 arg2->VarMaxLag(lhs_lag_equiv));
    }
    
    void
    BinaryOpNode::collectVARLHSVariable(set<expr_t> &result) const
    {
      cerr << "ERROR: you can only have variables or unary ops on LHS of VAR" << endl;
      exit(EXIT_FAILURE);
    }
    
    void
    BinaryOpNode::collectDynamicVariables(SymbolType type_arg, set<pair<int, int>> &result) const
    {
      arg1->collectDynamicVariables(type_arg, result);
      arg2->collectDynamicVariables(type_arg, result);
    }
    
    expr_t
    BinaryOpNode::Compute_RHS(expr_t arg1, expr_t arg2, int op, int op_type) const
    {
      switch (op_type)
        {
        case 0: /*Unary Operator*/
          switch (static_cast<UnaryOpcode>(op))
            {
            case UnaryOpcode::uminus:
              return datatree.AddUMinus(arg1);
            case UnaryOpcode::exp:
              return datatree.AddExp(arg1);
            case UnaryOpcode::log:
              return datatree.AddLog(arg1);
            case UnaryOpcode::log10:
              return datatree.AddLog10(arg1);
            default:
              cerr << "BinaryOpNode::Compute_RHS: case not handled";
              exit(EXIT_FAILURE);
            }
          break;
        case 1: /*Binary Operator*/
          switch (static_cast<BinaryOpcode>(op))
            {
            case BinaryOpcode::plus:
              return datatree.AddPlus(arg1, arg2);
            case BinaryOpcode::minus:
              return datatree.AddMinus(arg1, arg2);
            case BinaryOpcode::times:
              return datatree.AddTimes(arg1, arg2);
            case BinaryOpcode::divide:
              return datatree.AddDivide(arg1, arg2);
            case BinaryOpcode::power:
              return datatree.AddPower(arg1, arg2);
            default:
              cerr << "BinaryOpNode::Compute_RHS: case not handled";
              exit(EXIT_FAILURE);
            }
          break;
        }
      return nullptr;
    }
    
    void
    BinaryOpNode::computeSubExprContainingVariable(int symb_id, int lag, set<expr_t> &contain_var) const
    {
      arg1->computeSubExprContainingVariable(symb_id, lag, contain_var);
      arg2->computeSubExprContainingVariable(symb_id, lag, contain_var);
      if (contain_var.count(arg1) > 0 || contain_var.count(arg2) > 0)
        contain_var.insert(const_cast<BinaryOpNode *>(this));
    }
    
    BinaryOpNode *
    BinaryOpNode::normalizeEquationHelper(const set<expr_t> &contain_var, expr_t rhs) const
    {
      assert(contain_var.count(const_cast<BinaryOpNode *>(this)) > 0);
    
      bool arg1_contains_var = contain_var.count(arg1) > 0;
      bool arg2_contains_var = contain_var.count(arg2) > 0;
      assert(arg1_contains_var || arg2_contains_var);
    
      if (arg1_contains_var && arg2_contains_var)
        throw NormalizationFailed();
    
      switch (op_code)
        {
        case BinaryOpcode::plus:
          if (arg1_contains_var)
            rhs = datatree.AddMinus(rhs, arg2);
          else
            rhs = datatree.AddMinus(rhs, arg1);
          break;
        case BinaryOpcode::minus:
          if (arg1_contains_var)
            rhs = datatree.AddPlus(rhs, arg2);
          else
            rhs = datatree.AddMinus(arg1, rhs);
          break;
        case BinaryOpcode::times:
          if (arg1_contains_var)
            rhs = datatree.AddDivide(rhs, arg2);
          else
            rhs = datatree.AddDivide(rhs, arg1);
          break;
        case BinaryOpcode::divide:
          if (arg1_contains_var)
            rhs = datatree.AddTimes(rhs, arg2);
          else
            rhs = datatree.AddDivide(arg1, rhs);
          break;
        case BinaryOpcode::power:
          if (arg1_contains_var)
            rhs = datatree.AddPower(rhs, datatree.AddDivide(datatree.One, arg2));
          else
            // a^f(X)=rhs is normalized in f(X)=ln(rhs)/ln(a)
            rhs = datatree.AddDivide(datatree.AddLog(rhs), datatree.AddLog(arg1));
          break;
        case BinaryOpcode::equal:
          cerr << "BinaryOpCode::normalizeEquationHelper: this case should not happen" << endl;
          exit(EXIT_FAILURE);
        default:
          throw NormalizationFailed();
        }
    
      if (arg1_contains_var)
        return arg1->normalizeEquationHelper(contain_var, rhs);
      else
        return arg2->normalizeEquationHelper(contain_var, rhs);
    }
    
    BinaryOpNode *
    BinaryOpNode::normalizeEquation(int symb_id, int lag) const
    {
      assert(op_code == BinaryOpcode::equal);
    
      set<expr_t> contain_var;
      computeSubExprContainingVariable(symb_id, lag, contain_var);
    
      bool arg1_contains_var = contain_var.count(arg1) > 0;
      bool arg2_contains_var = contain_var.count(arg2) > 0;
      assert(arg1_contains_var || arg2_contains_var);
    
      if (arg1_contains_var && arg2_contains_var)
        throw NormalizationFailed();
    
      return arg1_contains_var ? arg1->normalizeEquationHelper(contain_var, arg2)
        : arg2->normalizeEquationHelper(contain_var, arg1);
    }
    
    expr_t
    BinaryOpNode::getChainRuleDerivative(int deriv_id, const map<int, BinaryOpNode *> &recursive_variables)
    {
      expr_t darg1 = arg1->getChainRuleDerivative(deriv_id, recursive_variables);
      expr_t darg2 = arg2->getChainRuleDerivative(deriv_id, recursive_variables);
      return composeDerivatives(darg1, darg2);
    }
    
    expr_t
    BinaryOpNode::buildSimilarBinaryOpNode(expr_t alt_arg1, expr_t alt_arg2, DataTree &alt_datatree) const
    {
      switch (op_code)
        {
        case BinaryOpcode::plus:
          return alt_datatree.AddPlus(alt_arg1, alt_arg2);
        case BinaryOpcode::minus:
          return alt_datatree.AddMinus(alt_arg1, alt_arg2);
        case BinaryOpcode::times:
          return alt_datatree.AddTimes(alt_arg1, alt_arg2);
        case BinaryOpcode::divide:
          return alt_datatree.AddDivide(alt_arg1, alt_arg2);
        case BinaryOpcode::power:
          return alt_datatree.AddPower(alt_arg1, alt_arg2);
        case BinaryOpcode::equal:
          return alt_datatree.AddEqual(alt_arg1, alt_arg2);
        case BinaryOpcode::max:
          return alt_datatree.AddMax(alt_arg1, alt_arg2);
        case BinaryOpcode::min:
          return alt_datatree.AddMin(alt_arg1, alt_arg2);
        case BinaryOpcode::less:
          return alt_datatree.AddLess(alt_arg1, alt_arg2);
        case BinaryOpcode::greater:
          return alt_datatree.AddGreater(alt_arg1, alt_arg2);
        case BinaryOpcode::lessEqual:
          return alt_datatree.AddLessEqual(alt_arg1, alt_arg2);
        case BinaryOpcode::greaterEqual:
          return alt_datatree.AddGreaterEqual(alt_arg1, alt_arg2);
        case BinaryOpcode::equalEqual:
          return alt_datatree.AddEqualEqual(alt_arg1, alt_arg2);
        case BinaryOpcode::different:
          return alt_datatree.AddDifferent(alt_arg1, alt_arg2);
        case BinaryOpcode::powerDeriv:
          return alt_datatree.AddPowerDeriv(alt_arg1, alt_arg2, powerDerivOrder);
        }
      // Suppress GCC warning
      exit(EXIT_FAILURE);
    }
    
    expr_t
    BinaryOpNode::toStatic(DataTree &static_datatree) const
    {
      expr_t sarg1 = arg1->toStatic(static_datatree);
      expr_t sarg2 = arg2->toStatic(static_datatree);
      return buildSimilarBinaryOpNode(sarg1, sarg2, static_datatree);
    }
    
    void
    BinaryOpNode::computeXrefs(EquationInfo &ei) const
    {
      arg1->computeXrefs(ei);
      arg2->computeXrefs(ei);
    }
    
    expr_t
    BinaryOpNode::clone(DataTree &datatree) const
    {
      expr_t substarg1 = arg1->clone(datatree);
      expr_t substarg2 = arg2->clone(datatree);
      return buildSimilarBinaryOpNode(substarg1, substarg2, datatree);
    }
    
    int
    BinaryOpNode::maxEndoLead() const
    {
      return max(arg1->maxEndoLead(), arg2->maxEndoLead());
    }
    
    int
    BinaryOpNode::maxExoLead() const
    {
      return max(arg1->maxExoLead(), arg2->maxExoLead());
    }
    
    int
    BinaryOpNode::maxEndoLag() const
    {
      return max(arg1->maxEndoLag(), arg2->maxEndoLag());
    }
    
    int
    BinaryOpNode::maxExoLag() const
    {
      return max(arg1->maxExoLag(), arg2->maxExoLag());
    }
    
    int
    BinaryOpNode::maxLead() const
    {
      return max(arg1->maxLead(), arg2->maxLead());
    }
    
    int
    BinaryOpNode::maxLag() const
    {
      return max(arg1->maxLag(), arg2->maxLag());
    }
    
    int
    BinaryOpNode::maxLagWithDiffsExpanded() const
    {
      return max(arg1->maxLagWithDiffsExpanded(), arg2->maxLagWithDiffsExpanded());
    }
    
    expr_t
    BinaryOpNode::undiff() const
    {
      expr_t arg1subst = arg1->undiff();
      expr_t arg2subst = arg2->undiff();
      return buildSimilarBinaryOpNode(arg1subst, arg2subst, datatree);
    }
    
    expr_t
    BinaryOpNode::decreaseLeadsLags(int n) const
    {
      expr_t arg1subst = arg1->decreaseLeadsLags(n);
      expr_t arg2subst = arg2->decreaseLeadsLags(n);
      return buildSimilarBinaryOpNode(arg1subst, arg2subst, datatree);
    }
    
    expr_t
    BinaryOpNode::decreaseLeadsLagsPredeterminedVariables() const
    {
      expr_t arg1subst = arg1->decreaseLeadsLagsPredeterminedVariables();
      expr_t arg2subst = arg2->decreaseLeadsLagsPredeterminedVariables();
      return buildSimilarBinaryOpNode(arg1subst, arg2subst, datatree);
    }
    
    expr_t
    BinaryOpNode::substituteEndoLeadGreaterThanTwo(subst_table_t &subst_table, vector<BinaryOpNode *> &neweqs, bool deterministic_model) const
    {
      expr_t arg1subst, arg2subst;
      int maxendolead1 = arg1->maxEndoLead(), maxendolead2 = arg2->maxEndoLead();
    
      if (maxendolead1 < 2 && maxendolead2 < 2)
        return const_cast<BinaryOpNode *>(this);
      if (deterministic_model)
        {
          arg1subst = maxendolead1 >= 2 ? arg1->substituteEndoLeadGreaterThanTwo(subst_table, neweqs, deterministic_model) : arg1;
          arg2subst = maxendolead2 >= 2 ? arg2->substituteEndoLeadGreaterThanTwo(subst_table, neweqs, deterministic_model) : arg2;
          return buildSimilarBinaryOpNode(arg1subst, arg2subst, datatree);
        }
      else
        switch (op_code)
          {
          case BinaryOpcode::plus:
          case BinaryOpcode::minus:
          case BinaryOpcode::equal:
            arg1subst = maxendolead1 >= 2 ? arg1->substituteEndoLeadGreaterThanTwo(subst_table, neweqs, deterministic_model) : arg1;
            arg2subst = maxendolead2 >= 2 ? arg2->substituteEndoLeadGreaterThanTwo(subst_table, neweqs, deterministic_model) : arg2;
            return buildSimilarBinaryOpNode(arg1subst, arg2subst, datatree);
          case BinaryOpcode::times:
          case BinaryOpcode::divide:
            if (maxendolead1 >= 2 && maxendolead2 == 0 && arg2->maxExoLead() == 0)
              {
                arg1subst = arg1->substituteEndoLeadGreaterThanTwo(subst_table, neweqs, deterministic_model);
                return buildSimilarBinaryOpNode(arg1subst, arg2, datatree);
              }
            if (maxendolead1 == 0 && arg1->maxExoLead() == 0
                && maxendolead2 >= 2 && op_code == BinaryOpcode::times)
              {
                arg2subst = arg2->substituteEndoLeadGreaterThanTwo(subst_table, neweqs, deterministic_model);
                return buildSimilarBinaryOpNode(arg1, arg2subst, datatree);
              }
            return createEndoLeadAuxiliaryVarForMyself(subst_table, neweqs);
          default:
            return createEndoLeadAuxiliaryVarForMyself(subst_table, neweqs);
          }
    }
    
    expr_t
    BinaryOpNode::substituteEndoLagGreaterThanTwo(subst_table_t &subst_table, vector<BinaryOpNode *> &neweqs) const
    {
      expr_t arg1subst = arg1->substituteEndoLagGreaterThanTwo(subst_table, neweqs);
      expr_t arg2subst = arg2->substituteEndoLagGreaterThanTwo(subst_table, neweqs);
      return buildSimilarBinaryOpNode(arg1subst, arg2subst, datatree);
    }
    
    expr_t
    BinaryOpNode::substituteExoLead(subst_table_t &subst_table, vector<BinaryOpNode *> &neweqs, bool deterministic_model) const
    {
      expr_t arg1subst, arg2subst;
      int maxexolead1 = arg1->maxExoLead(), maxexolead2 = arg2->maxExoLead();
    
      if (maxexolead1 < 1 && maxexolead2 < 1)
        return const_cast<BinaryOpNode *>(this);
      if (deterministic_model)
        {
          arg1subst = maxexolead1 >= 1 ? arg1->substituteExoLead(subst_table, neweqs, deterministic_model) : arg1;
          arg2subst = maxexolead2 >= 1 ? arg2->substituteExoLead(subst_table, neweqs, deterministic_model) : arg2;
          return buildSimilarBinaryOpNode(arg1subst, arg2subst, datatree);
        }
      else
        switch (op_code)
          {
          case BinaryOpcode::plus:
          case BinaryOpcode::minus:
          case BinaryOpcode::equal:
            arg1subst = maxexolead1 >= 1 ? arg1->substituteExoLead(subst_table, neweqs, deterministic_model) : arg1;
            arg2subst = maxexolead2 >= 1 ? arg2->substituteExoLead(subst_table, neweqs, deterministic_model) : arg2;
            return buildSimilarBinaryOpNode(arg1subst, arg2subst, datatree);
          case BinaryOpcode::times:
          case BinaryOpcode::divide:
            if (maxexolead1 >= 1 && maxexolead2 == 0 && arg2->maxEndoLead() == 0)
              {
                arg1subst = arg1->substituteExoLead(subst_table, neweqs, deterministic_model);
                return buildSimilarBinaryOpNode(arg1subst, arg2, datatree);
              }
            if (maxexolead1 == 0 && arg1->maxEndoLead() == 0
                && maxexolead2 >= 1 && op_code == BinaryOpcode::times)
              {
                arg2subst = arg2->substituteExoLead(subst_table, neweqs, deterministic_model);
                return buildSimilarBinaryOpNode(arg1, arg2subst, datatree);
              }
            return createExoLeadAuxiliaryVarForMyself(subst_table, neweqs);
          default:
            return createExoLeadAuxiliaryVarForMyself(subst_table, neweqs);
          }
    }
    
    expr_t
    BinaryOpNode::substituteExoLag(subst_table_t &subst_table, vector<BinaryOpNode *> &neweqs) const
    {
      expr_t arg1subst = arg1->substituteExoLag(subst_table, neweqs);
      expr_t arg2subst = arg2->substituteExoLag(subst_table, neweqs);
      return buildSimilarBinaryOpNode(arg1subst, arg2subst, datatree);
    }
    
    expr_t
    BinaryOpNode::substituteExpectation(subst_table_t &subst_table, vector<BinaryOpNode *> &neweqs, bool partial_information_model) const
    {
      expr_t arg1subst = arg1->substituteExpectation(subst_table, neweqs, partial_information_model);
      expr_t arg2subst = arg2->substituteExpectation(subst_table, neweqs, partial_information_model);
      return buildSimilarBinaryOpNode(arg1subst, arg2subst, datatree);
    }
    
    expr_t
    BinaryOpNode::substituteAdl() const
    {
      expr_t arg1subst = arg1->substituteAdl();
      expr_t arg2subst = arg2->substituteAdl();
      return buildSimilarBinaryOpNode(arg1subst, arg2subst, datatree);
    }
    
    expr_t
    BinaryOpNode::substituteModelLocalVariables() const
    {
      expr_t arg1subst = arg1->substituteModelLocalVariables();
      expr_t arg2subst = arg2->substituteModelLocalVariables();
      return buildSimilarBinaryOpNode(arg1subst, arg2subst, datatree);
    }
    
    expr_t
    BinaryOpNode::substituteVarExpectation(const map<string, expr_t> &subst_table) const
    {
      expr_t arg1subst = arg1->substituteVarExpectation(subst_table);
      expr_t arg2subst = arg2->substituteVarExpectation(subst_table);
      return buildSimilarBinaryOpNode(arg1subst, arg2subst, datatree);
    }
    
    void
    BinaryOpNode::findUnaryOpNodesForAuxVarCreation(lag_equivalence_table_t &nodes) const
    {
      arg1->findUnaryOpNodesForAuxVarCreation(nodes);
      arg2->findUnaryOpNodesForAuxVarCreation(nodes);
    }
    
    void
    BinaryOpNode::findDiffNodes(lag_equivalence_table_t &nodes) const
    {
      arg1->findDiffNodes(nodes);
      arg2->findDiffNodes(nodes);
    }
    
    expr_t
    BinaryOpNode::substituteDiff(const lag_equivalence_table_t &nodes, subst_table_t &subst_table,
                                 vector<BinaryOpNode *> &neweqs) const
    {
      expr_t arg1subst = arg1->substituteDiff(nodes, subst_table, neweqs);
      expr_t arg2subst = arg2->substituteDiff(nodes, subst_table, neweqs);
      return buildSimilarBinaryOpNode(arg1subst, arg2subst, datatree);
    }
    
    expr_t
    BinaryOpNode::substituteUnaryOpNodes(const lag_equivalence_table_t &nodes, subst_table_t &subst_table, vector<BinaryOpNode *> &neweqs) const
    {
      expr_t arg1subst = arg1->substituteUnaryOpNodes(nodes, subst_table, neweqs);
      expr_t arg2subst = arg2->substituteUnaryOpNodes(nodes, subst_table, neweqs);
      return buildSimilarBinaryOpNode(arg1subst, arg2subst, datatree);
    }
    
    int
    BinaryOpNode::countDiffs() const
    {
      return max(arg1->countDiffs(), arg2->countDiffs());
    }
    
    expr_t
    BinaryOpNode::substitutePacExpectation(const string &name, expr_t subexpr)
    {
      expr_t arg1subst = arg1->substitutePacExpectation(name, subexpr);
      expr_t arg2subst = arg2->substitutePacExpectation(name, subexpr);
      return buildSimilarBinaryOpNode(arg1subst, arg2subst, datatree);
    }
    
    expr_t
    BinaryOpNode::substitutePacTargetNonstationary(const string &name, expr_t subexpr)
    {
      expr_t arg1subst = arg1->substitutePacTargetNonstationary(name, subexpr);
      expr_t arg2subst = arg2->substitutePacTargetNonstationary(name, subexpr);
      return buildSimilarBinaryOpNode(arg1subst, arg2subst, datatree);
    }
    
    expr_t
    BinaryOpNode::differentiateForwardVars(const vector<string> &subset, subst_table_t &subst_table, vector<BinaryOpNode *> &neweqs) const
    {
      expr_t arg1subst = arg1->differentiateForwardVars(subset, subst_table, neweqs);
      expr_t arg2subst = arg2->differentiateForwardVars(subset, subst_table, neweqs);
      return buildSimilarBinaryOpNode(arg1subst, arg2subst, datatree);
    }
    
    expr_t
    BinaryOpNode::addMultipliersToConstraints(int i)
    {
      int symb_id = datatree.symbol_table.addMultiplierAuxiliaryVar(i);
      expr_t newAuxLM = datatree.AddVariable(symb_id, 0);
      return datatree.AddEqual(datatree.AddTimes(newAuxLM, datatree.AddMinus(arg1, arg2)), datatree.Zero);
    }
    
    bool
    BinaryOpNode::isNumConstNodeEqualTo(double value) const
    {
      return false;
    }
    
    bool
    BinaryOpNode::isVariableNodeEqualTo(SymbolType type_arg, int variable_id, int lag_arg) const
    {
      return false;
    }
    
    bool
    BinaryOpNode::containsPacExpectation(const string &pac_model_name) const
    {
      return arg1->containsPacExpectation(pac_model_name) || arg2->containsPacExpectation(pac_model_name);
    }
    
    bool
    BinaryOpNode::containsPacTargetNonstationary(const string &pac_model_name) const
    {
      return arg1->containsPacTargetNonstationary(pac_model_name) || arg2->containsPacTargetNonstationary(pac_model_name);
    }
    
    expr_t
    BinaryOpNode::replaceTrendVar() const
    {
      expr_t arg1subst = arg1->replaceTrendVar();
      expr_t arg2subst = arg2->replaceTrendVar();
      return buildSimilarBinaryOpNode(arg1subst, arg2subst, datatree);
    }
    
    expr_t
    BinaryOpNode::detrend(int symb_id, bool log_trend, expr_t trend) const
    {
      expr_t arg1subst = arg1->detrend(symb_id, log_trend, trend);
      expr_t arg2subst = arg2->detrend(symb_id, log_trend, trend);
      return buildSimilarBinaryOpNode(arg1subst, arg2subst, datatree);
    }
    
    expr_t
    BinaryOpNode::removeTrendLeadLag(const map<int, expr_t> &trend_symbols_map) const
    {
      expr_t arg1subst = arg1->removeTrendLeadLag(trend_symbols_map);
      expr_t arg2subst = arg2->removeTrendLeadLag(trend_symbols_map);
      return buildSimilarBinaryOpNode(arg1subst, arg2subst, datatree);
    }
    
    bool
    BinaryOpNode::isInStaticForm() const
    {
      return arg1->isInStaticForm() && arg2->isInStaticForm();
    }
    
    bool
    BinaryOpNode::findTargetVariableHelper1(int lhs_symb_id, int rhs_symb_id) const
    {
      if (lhs_symb_id == rhs_symb_id)
        return true;
    
      try
        {
          if (datatree.symbol_table.isAuxiliaryVariable(rhs_symb_id)
              && lhs_symb_id == datatree.symbol_table.getOrigSymbIdForAuxVar(rhs_symb_id))
            return true;
        }
      catch (...)
        {
        }
      return false;
    }
    
    int
    BinaryOpNode::findTargetVariableHelper(const expr_t arg1, const expr_t arg2,
                                           int lhs_symb_id) const
    {
      set<int> params;
      arg1->collectVariables(SymbolType::parameter, params);
      if (params.size() != 1)
        return -1;
    
      set<pair<int, int>> endogs;
      arg2->collectDynamicVariables(SymbolType::endogenous, endogs);
      if (auto testarg2 = dynamic_cast<BinaryOpNode *>(arg2);
          endogs.size() == 2 && testarg2 && testarg2->op_code == BinaryOpcode::minus
          && dynamic_cast<VariableNode *>(testarg2->arg1)
          && dynamic_cast<VariableNode *>(testarg2->arg2))
        {
          if (findTargetVariableHelper1(lhs_symb_id, endogs.begin()->first))
            return endogs.rbegin()->first;
          else if (findTargetVariableHelper1(lhs_symb_id, endogs.rbegin()->first))
            return endogs.begin()->first;
        }
      return -1;
    }
    
    int
    BinaryOpNode::findTargetVariable(int lhs_symb_id) const
    {
      int retval = findTargetVariableHelper(arg1, arg2, lhs_symb_id);
      if (retval < 0)
        retval = findTargetVariableHelper(arg2, arg1, lhs_symb_id);
      if (retval < 0)
        retval = arg1->findTargetVariable(lhs_symb_id);
      if (retval < 0)
        retval = arg2->findTargetVariable(lhs_symb_id);
      return retval;
    }
    
    void
    BinaryOpNode::getPacAREC(int lhs_symb_id, int lhs_orig_symb_id,
                             pair<int, vector<tuple<int, bool, int>>> &ec_params_and_vars,
                             vector<tuple<int, int, int>> &ar_params_and_vars,
                             vector<tuple<int, int, int, double>> &additive_vars_params_and_constants) const
    {
      ec_params_and_vars.first = -1;
    
      vector<pair<expr_t, int>> terms;
      decomposeAdditiveTerms(terms, 1);
      for (auto it = terms.begin(); it != terms.end(); ++it)
        if (auto bopn = dynamic_cast<BinaryOpNode *>(it->first); bopn)
          {
            try
              {
                auto [param_id, target_id] = bopn->matchParamTimesTargetMinusVariable(lhs_orig_symb_id);
                ec_params_and_vars = { param_id, { { target_id, true, 1 }, { lhs_orig_symb_id, false, -1 }}};
                terms.erase(it);
                break;
              }
            catch (MatchFailureException &e)
              {
              }
          }
    
      if (ec_params_and_vars.first < 0)
        {
          cerr << "Error finding EC part of PAC equation" << endl;
          exit(EXIT_FAILURE);
        }
    
      for (const auto &it : terms)
        {
          if (dynamic_cast<PacExpectationNode *>(it.first))
            continue;
    
          pair<int, vector<tuple<int, int, int, double>>> m;
          try
            {
              m = {-1, {it.first->matchVariableTimesConstantTimesParam()}};
            }
          catch (MatchFailureException &e)
            {
              try
                {
                  m = it.first->matchParamTimesLinearCombinationOfVariables();
                }
              catch (MatchFailureException &e)
                {
                  cerr << "Unsupported expression in PAC equation" << endl;
                  exit(EXIT_FAILURE);
                }
            }
    
          for (auto &t : m.second)
            get<3>(t) *= it.second; // Update sign of constants
    
          int pid = get<0>(m);
          for (auto [vid, vlag, pidtmp, constant] : m.second)
            {
              if (pid == -1)
                pid = pidtmp;
              else if (pidtmp >= 0)
                {
                  cerr << "unexpected parameter found in PAC equation" << endl;
                  exit(EXIT_FAILURE);
                }
    
              if (int vidorig = datatree.symbol_table.getUltimateOrigSymbID(vid);
                  vidorig == lhs_symb_id || vidorig == lhs_orig_symb_id)
                {
                  // This is an autoregressive term
                  if (constant != 1 || pid == -1 || !datatree.symbol_table.isDiffAuxiliaryVariable(vid))
                    {
                      cerr << "BinaryOpNode::getPacAREC: autoregressive terms must be of the form 'parameter*diff_lagged_variable" << endl;
                      exit(EXIT_FAILURE);
                    }
                  int ar_lag = datatree.symbol_table.getOrigLeadLagForDiffAuxVar(vid);
                  if (static_cast<int>(ar_params_and_vars.size()) < ar_lag)
                    ar_params_and_vars.resize(ar_lag, { -1, -1, 0 });
                  ar_params_and_vars[ar_lag-1] = { pid, vid, vlag };
                }
              else
                // This is a residual additive term
                additive_vars_params_and_constants.emplace_back(vid, vlag, pid, constant);
            }
        }
    }
    
    bool
    BinaryOpNode::isParamTimesEndogExpr() const
    {
      if (op_code == BinaryOpcode::times)
        {
          set<int> params;
          auto test_arg1 = dynamic_cast<VariableNode *>(arg1);
          auto test_arg2 = dynamic_cast<VariableNode *>(arg2);
          if (test_arg1)
            arg1->collectVariables(SymbolType::parameter, params);
          else if (test_arg2)
            arg2->collectVariables(SymbolType::parameter, params);
          else
            return false;
    
          if (params.size() != 1)
            return false;
    
          params.clear();
          set<pair<int, int>> endogs, exogs;
          if (test_arg1)
            {
              arg2->collectDynamicVariables(SymbolType::endogenous, endogs);
              arg2->collectDynamicVariables(SymbolType::exogenous, exogs);
              arg2->collectVariables(SymbolType::parameter, params);
              if (params.size() == 0 && exogs.size() == 0 && endogs.size() >= 1)
                return true;
            }
          else
            {
              arg1->collectDynamicVariables(SymbolType::endogenous, endogs);
              arg1->collectDynamicVariables(SymbolType::exogenous, exogs);
              arg1->collectVariables(SymbolType::parameter, params);
              if (params.size() == 0 && exogs.size() == 0 && endogs.size() >= 1)
                return true;
            }
        }
      else if (op_code == BinaryOpcode::plus)
        return arg1->isParamTimesEndogExpr() || arg2->isParamTimesEndogExpr();
      return false;
    }
    
    expr_t
    BinaryOpNode::getPacNonOptimizingPart(int optim_share_symb_id) const
    {
      vector<pair<expr_t, int>> factors;
      decomposeMultiplicativeFactors(factors);
    
      // Search for a factor of the form 1-optim_share
      expr_t one_minus_optim_share = nullptr;
      for (auto [factor, exponent] : factors)
        {
          auto bopn = dynamic_cast<BinaryOpNode *>(factor);
          if (exponent != 1 || !bopn || bopn->op_code != BinaryOpcode::minus)
            continue;
          auto arg1 = dynamic_cast<NumConstNode *>(bopn->arg1);
          auto arg2 = dynamic_cast<VariableNode *>(bopn->arg2);
          if (arg1 && arg2 && arg1->eval({}) == 1 && arg2->symb_id == optim_share_symb_id)
            {
              one_minus_optim_share = factor;
              break;
            }
        }
    
      if (!one_minus_optim_share)
        return nullptr;
    
      // Construct the product formed by the other factors and return it
      expr_t non_optim_part = datatree.One;
      for (auto [factor, exponent] : factors)
        if (factor != one_minus_optim_share)
          if (exponent == 1)
            non_optim_part = datatree.AddTimes(non_optim_part, factor);
          else
            non_optim_part = datatree.AddDivide(non_optim_part, factor);
    
      return non_optim_part;
    }
    
    pair<int, expr_t>
    BinaryOpNode::getPacOptimizingShareAndExprNodesHelper(int lhs_symb_id, int lhs_orig_symb_id) const
    {
      int optim_param_symb_id = -1;
      expr_t optim_part = nullptr;
      set<int> endogs;
      collectVariables(SymbolType::endogenous, endogs);
      // Test whether it contains the LHS in level
      if (endogs.count(lhs_orig_symb_id) > 0)
        {
          set<int> params;
          if (arg1->isParamTimesEndogExpr() && !arg2->isParamTimesEndogExpr())
            {
              optim_part = arg1;
              arg2->collectVariables(SymbolType::parameter, params);
              optim_param_symb_id = *(params.begin());
            }
          else if (arg2->isParamTimesEndogExpr() && !arg1->isParamTimesEndogExpr())
            {
              optim_part = arg2;
              arg1->collectVariables(SymbolType::parameter, params);
              optim_param_symb_id = *(params.begin());
            }
        }
      return {optim_param_symb_id, optim_part};
    }
    
    tuple<int, expr_t, expr_t, expr_t>
    BinaryOpNode::getPacOptimizingShareAndExprNodes(int lhs_symb_id, int lhs_orig_symb_id) const
    {
      vector<pair<expr_t, int>> terms;
      decomposeAdditiveTerms(terms, 1);
      for (auto &it : terms)
        if (dynamic_cast<PacExpectationNode *>(it.first))
          // if the pac_expectation operator is additive in the expression
          // there are no optimizing shares
          return {-1, nullptr, nullptr, nullptr};
    
      int optim_share;
      expr_t optim_part, non_optim_part, additive_part;
      optim_part = non_optim_part = additive_part = nullptr;
    
      for (auto it = terms.begin(); it != terms.end(); ++it)
        if (auto bopn = dynamic_cast<BinaryOpNode *>(it->first); bopn)
          {
            tie(optim_share, optim_part)
              = bopn->getPacOptimizingShareAndExprNodesHelper(lhs_symb_id, lhs_orig_symb_id);
            if (optim_share >= 0 && optim_part)
              {
                terms.erase(it);
                break;
              }
          }
    
      if (!optim_part)
        return {-1, nullptr, nullptr, nullptr};
    
      for (auto it = terms.begin(); it != terms.end(); ++it)
        if (auto bopn = dynamic_cast<BinaryOpNode *>(it->first); bopn)
          {
            non_optim_part = bopn->getPacNonOptimizingPart(optim_share);
            if (non_optim_part)
              {
                terms.erase(it);
                break;
              }
          }
    
      if (!non_optim_part)
        return {-1, nullptr, nullptr, nullptr};
      else
        {
          additive_part = datatree.Zero;
          for (auto it : terms)
            additive_part = datatree.AddPlus(additive_part, it.first);
          if (additive_part == datatree.Zero)
            additive_part = nullptr;
        }
    
      return {optim_share, optim_part, non_optim_part, additive_part};
    }
    
    void
    BinaryOpNode::fillAutoregressiveRow(int eqn, const vector<int> &lhs, map<tuple<int, int, int>, expr_t> &AR) const
    {
      vector<pair<expr_t, int>> terms;
      decomposeAdditiveTerms(terms, 1);
      for (const auto &it : terms)
        {
          int vid, lag, param_id;
          double constant;
          try
            {
              tie(vid, lag, param_id, constant) = it.first->matchVariableTimesConstantTimesParam();
              constant *= it.second;
            }
          catch (MatchFailureException &e)
            {
              continue;
            }
    
          if (datatree.symbol_table.isDiffAuxiliaryVariable(vid))
            {
              lag = -datatree.symbol_table.getOrigLeadLagForDiffAuxVar(vid);
              vid = datatree.symbol_table.getOrigSymbIdForDiffAuxVar(vid);
            }
    
          if (find(lhs.begin(), lhs.end(), vid) == lhs.end())
            continue;
    
          if (AR.find({eqn, -lag, vid}) != AR.end())
            {
              cerr << "BinaryOpNode::fillAutoregressiveRow: Error filling AR matrix: "
                   << "lag/symb_id encountered more than once in equation" << endl;
              exit(EXIT_FAILURE);
            }
          if (constant != 1 || param_id == -1)
            {
              cerr << "BinaryOpNode::fillAutoregressiveRow: autoregressive terms must be of the form 'parameter*lagged_variable" << endl;
              exit(EXIT_FAILURE);
            }
          AR[{eqn, -lag, vid}] = datatree.AddVariable(param_id);
        }
    }
    
    void
    BinaryOpNode::findConstantEquations(map<VariableNode *, NumConstNode *> &table) const
    {
      if (op_code == BinaryOpcode::equal)
        {
          // The variable must be contemporaneous (see #83)
          if (auto varg1 = dynamic_cast<VariableNode *>(arg1);
              varg1 && varg1->lag == 0 && dynamic_cast<NumConstNode *>(arg2))
            table[varg1] = dynamic_cast<NumConstNode *>(arg2);
          else if (auto varg2 = dynamic_cast<VariableNode *>(arg2);
                   varg2 && varg2->lag == 0 && dynamic_cast<NumConstNode *>(arg1))
            table[varg2] = dynamic_cast<NumConstNode *>(arg1);
        }
    }
    
    expr_t
    BinaryOpNode::replaceVarsInEquation(map<VariableNode *, NumConstNode *> &table) const
    {
      if (op_code == BinaryOpcode::equal)
        for (auto &it : table)
          if ((it.first == arg1 && it.second == arg2) || (it.first == arg2 && it.second == arg1))
            return const_cast<BinaryOpNode *>(this);
      expr_t arg1subst = arg1->replaceVarsInEquation(table);
      expr_t arg2subst = arg2->replaceVarsInEquation(table);
      return buildSimilarBinaryOpNode(arg1subst, arg2subst, datatree);
    }
    
    expr_t
    BinaryOpNode::substituteStaticAuxiliaryVariable() const
    {
      expr_t arg1subst = arg1->substituteStaticAuxiliaryVariable();
      expr_t arg2subst = arg2->substituteStaticAuxiliaryVariable();
      return buildSimilarBinaryOpNode(arg1subst, arg2subst, datatree);
    }
    
    expr_t
    BinaryOpNode::substituteStaticAuxiliaryDefinition() const
    {
      expr_t arg2subst = arg2->substituteStaticAuxiliaryVariable();
      return buildSimilarBinaryOpNode(arg1, arg2subst, datatree);
    }
    
    void
    BinaryOpNode::matchMatchedMoment(vector<int> &symb_ids, vector<int> &lags, vector<int> &powers) const
    {
      if (op_code == BinaryOpcode::times)
        {
          arg1->matchMatchedMoment(symb_ids, lags, powers);
          arg2->matchMatchedMoment(symb_ids, lags, powers);
        }
      else if (op_code == BinaryOpcode::power)
        {
          if (!dynamic_cast<const VariableNode *>(arg1))
            throw MatchFailureException("First argument of power expression must be a variable");
          auto ncn = dynamic_cast<const NumConstNode *>(arg2);
          if (!ncn)
            throw MatchFailureException("Second argument of power expression must be a positive integer");
          double c = datatree.num_constants.getDouble(ncn->id);
          if (c <= 0 || round(c) != c)
            throw MatchFailureException("Second argument of power expression must be a positive integer");
          arg1->matchMatchedMoment(symb_ids, lags, powers);
          powers.back() = static_cast<int>(c);
        }
      else
        throw MatchFailureException("Unsupported binary operator");
    }
    
    
    TrinaryOpNode::TrinaryOpNode(DataTree &datatree_arg, int idx_arg, const expr_t arg1_arg,
                                 TrinaryOpcode op_code_arg, const expr_t arg2_arg, const expr_t arg3_arg) :
      ExprNode{datatree_arg, idx_arg},
      arg1{arg1_arg},
      arg2{arg2_arg},
      arg3{arg3_arg},
      op_code{op_code_arg}
    {
    }
    
    void
    TrinaryOpNode::prepareForDerivation()
    {
      if (preparedForDerivation)
        return;
    
      preparedForDerivation = true;
    
      arg1->prepareForDerivation();
      arg2->prepareForDerivation();
      arg3->prepareForDerivation();
    
      // Non-null derivatives are the union of those of the arguments
      // Compute set union of arg{1,2,3}->non_null_derivatives
      set<int> non_null_derivatives_tmp;
      set_union(arg1->non_null_derivatives.begin(),
                arg1->non_null_derivatives.end(),
                arg2->non_null_derivatives.begin(),
                arg2->non_null_derivatives.end(),
                inserter(non_null_derivatives_tmp, non_null_derivatives_tmp.begin()));
      set_union(non_null_derivatives_tmp.begin(),
                non_null_derivatives_tmp.end(),
                arg3->non_null_derivatives.begin(),
                arg3->non_null_derivatives.end(),
                inserter(non_null_derivatives, non_null_derivatives.begin()));
    }
    
    expr_t
    TrinaryOpNode::composeDerivatives(expr_t darg1, expr_t darg2, expr_t darg3)
    {
    
      expr_t t11, t12, t13, t14, t15;
    
      switch (op_code)
        {
        case TrinaryOpcode::normcdf:
          // normal pdf is inlined in the tree
          expr_t y;
          // sqrt(2*pi)
          t14 = datatree.AddSqrt(datatree.AddTimes(datatree.Two, datatree.Pi));
          // x - mu
          t12 = datatree.AddMinus(arg1, arg2);
          // y = (x-mu)/sigma
          y = datatree.AddDivide(t12, arg3);
          // (x-mu)^2/sigma^2
          t12 = datatree.AddTimes(y, y);
          // -(x-mu)^2/sigma^2
          t13 = datatree.AddUMinus(t12);
          // -((x-mu)^2/sigma^2)/2
          t12 = datatree.AddDivide(t13, datatree.Two);
          // exp(-((x-mu)^2/sigma^2)/2)
          t13 = datatree.AddExp(t12);
          // derivative of a standardized normal
          // t15 = (1/sqrt(2*pi))*exp(-y^2/2)
          t15 = datatree.AddDivide(t13, t14);
          // derivatives thru x
          t11 = datatree.AddDivide(darg1, arg3);
          // derivatives thru mu
          t12 = datatree.AddDivide(darg2, arg3);
          // intermediary sum
          t14 = datatree.AddMinus(t11, t12);
          // derivatives thru sigma
          t11 = datatree.AddDivide(y, arg3);
          t12 = datatree.AddTimes(t11, darg3);
          //intermediary sum
          t11 = datatree.AddMinus(t14, t12);
          // total derivative:
          // (darg1/sigma - darg2/sigma - darg3*(x-mu)/sigma^2) * t15
          // where t15 is the derivative of a standardized normal
          return datatree.AddTimes(t11, t15);
        case TrinaryOpcode::normpdf:
          // (x - mu)
          t11 = datatree.AddMinus(arg1, arg2);
          // (x - mu)/sigma
          t12 = datatree.AddDivide(t11, arg3);
          // darg3 * (x - mu)/sigma
          t11 = datatree.AddTimes(darg3, t12);
          // darg2 - darg1
          t13 = datatree.AddMinus(darg2, darg1);
          // darg2 - darg1 + darg3 * (x - mu)/sigma
          t14 = datatree.AddPlus(t13, t11);
          // ((x - mu)/sigma) * (darg2 - darg1 + darg3 * (x - mu)/sigma)
          t11 = datatree.AddTimes(t12, t14);
          // ((x - mu)/sigma) * (darg2 - darg1 + darg3 * (x - mu)/sigma) - darg3
          t12 = datatree.AddMinus(t11, darg3);
          // this / sigma
          t11 = datatree.AddDivide(this, arg3);
          // total derivative:
          // (this / sigma) * (((x - mu)/sigma) * (darg2 - darg1 + darg3 * (x - mu)/sigma) - darg3)
          return datatree.AddTimes(t11, t12);
        }
      // Suppress GCC warning
      exit(EXIT_FAILURE);
    }
    
    expr_t
    TrinaryOpNode::computeDerivative(int deriv_id)
    {
      expr_t darg1 = arg1->getDerivative(deriv_id);
      expr_t darg2 = arg2->getDerivative(deriv_id);
      expr_t darg3 = arg3->getDerivative(deriv_id);
      return composeDerivatives(darg1, darg2, darg3);
    }
    
    int
    TrinaryOpNode::precedence(ExprNodeOutputType output_type, const temporary_terms_t &temporary_terms) const
    {
      // A temporary term behaves as a variable
      if (temporary_terms.find(const_cast<TrinaryOpNode *>(this)) != temporary_terms.end())
        return 100;
    
      switch (op_code)
        {
        case TrinaryOpcode::normcdf:
        case TrinaryOpcode::normpdf:
          return 100;
        }
      // Suppress GCC warning
      exit(EXIT_FAILURE);
    }
    
    int
    TrinaryOpNode::cost(const map<pair<int, int>, temporary_terms_t> &temp_terms_map, bool is_matlab) const
    {
      // For a temporary term, the cost is null
      for (const auto &it : temp_terms_map)
        if (it.second.find(const_cast<TrinaryOpNode *>(this)) != it.second.end())
          return 0;
    
      int arg_cost = arg1->cost(temp_terms_map, is_matlab)
        + arg2->cost(temp_terms_map, is_matlab)
        + arg3->cost(temp_terms_map, is_matlab);
    
      return cost(arg_cost, is_matlab);
    }
    
    int
    TrinaryOpNode::cost(const vector<vector<temporary_terms_t>> &blocks_temporary_terms, bool is_matlab) const
    {
      // For a temporary term, the cost is null
      for (const auto &blk_tt : blocks_temporary_terms)
        for (const auto &eq_tt : blk_tt)
          if (eq_tt.find(const_cast<TrinaryOpNode *>(this)) != eq_tt.end())
            return 0;
    
      int arg_cost = arg1->cost(blocks_temporary_terms, is_matlab)
        + arg2->cost(blocks_temporary_terms, is_matlab)
        + arg3->cost(blocks_temporary_terms, is_matlab);
    
      return cost(arg_cost, is_matlab);
    }
    
    int
    TrinaryOpNode::cost(int cost, bool is_matlab) const
    {
      if (is_matlab)
        // Cost for Matlab files
        switch (op_code)
          {
          case TrinaryOpcode::normcdf:
          case TrinaryOpcode::normpdf:
            return cost+1000;
          }
      else
        // Cost for C files
        switch (op_code)
          {
          case TrinaryOpcode::normcdf:
          case TrinaryOpcode::normpdf:
            return cost+1000;
          }
      // Suppress GCC warning
      exit(EXIT_FAILURE);
    }
    
    void
    TrinaryOpNode::computeTemporaryTerms(const pair<int, int> &derivOrder,
                                         map<pair<int, int>, temporary_terms_t> &temp_terms_map,
                                         map<expr_t, pair<int, pair<int, int>>> &reference_count,
                                         bool is_matlab) const
    {
      expr_t this2 = const_cast<TrinaryOpNode *>(this);
      if (auto it = reference_count.find(this2);
          it == reference_count.end())
        {
          // If this node has never been encountered, set its ref count to one,
          //  and travel through its children
          reference_count[this2] = { 1, derivOrder };
          arg1->computeTemporaryTerms(derivOrder, temp_terms_map, reference_count, is_matlab);
          arg2->computeTemporaryTerms(derivOrder, temp_terms_map, reference_count, is_matlab);
          arg3->computeTemporaryTerms(derivOrder, temp_terms_map, reference_count, is_matlab);
        }
      else
        {
          // If the node has already been encountered, increment its ref count
          //  and declare it as a temporary term if it is too costly
          auto &[nref, min_order] = it->second;
          nref++;
          if (nref * cost(temp_terms_map, is_matlab) > min_cost(is_matlab))
            temp_terms_map[min_order].insert(this2);
        }
    }
    
    void
    TrinaryOpNode::computeBlockTemporaryTerms(int blk, int eq, vector<vector<temporary_terms_t>> &blocks_temporary_terms,
                                              map<expr_t, tuple<int, int, int>> &reference_count) const
    {
      expr_t this2 = const_cast<TrinaryOpNode *>(this);
      if (auto it = reference_count.find(this2);
          it == reference_count.end())
        {
          reference_count[this2] = { 1, blk, eq };
          arg1->computeBlockTemporaryTerms(blk, eq, blocks_temporary_terms, reference_count);
          arg2->computeBlockTemporaryTerms(blk, eq, blocks_temporary_terms, reference_count);
          arg3->computeBlockTemporaryTerms(blk, eq, blocks_temporary_terms, reference_count);
        }
      else
        {
          auto &[nref, first_blk, first_eq] = it->second;
          nref++;
          if (nref * cost(blocks_temporary_terms, false) > min_cost_c)
            blocks_temporary_terms[first_blk][first_eq].insert(this2);
        }
    }
    
    double
    TrinaryOpNode::eval_opcode(double v1, TrinaryOpcode op_code, double v2, double v3) noexcept(false)
    {
      switch (op_code)
        {
        case TrinaryOpcode::normcdf:
          return (0.5*(1+erf((v1-v2)/v3/M_SQRT2)));
        case TrinaryOpcode::normpdf:
          return (1/(v3*sqrt(2*M_PI)*exp(pow((v1-v2)/v3, 2)/2)));
        }
      // Suppress GCC warning
      exit(EXIT_FAILURE);
    }
    
    double
    TrinaryOpNode::eval(const eval_context_t &eval_context) const noexcept(false)
    {
      double v1 = arg1->eval(eval_context);
      double v2 = arg2->eval(eval_context);
      double v3 = arg3->eval(eval_context);
    
      return eval_opcode(v1, op_code, v2, v3);
    }
    
    void
    TrinaryOpNode::compile(ostream &CompileCode, unsigned int &instruction_number,
                           bool lhs_rhs, const temporary_terms_t &temporary_terms,
                           const temporary_terms_idxs_t &temporary_terms_idxs, bool dynamic, bool steady_dynamic,
                           const deriv_node_temp_terms_t &tef_terms) const
    {
      // If current node is a temporary term
      if (auto this2 = const_cast<TrinaryOpNode *>(this);
          temporary_terms.find(this2) != temporary_terms.end())
        {
          if (dynamic)
            {
              FLDT_ fldt(temporary_terms_idxs.at(this2));
              fldt.write(CompileCode, instruction_number);
            }
          else
            {
              FLDST_ fldst(temporary_terms_idxs.at(this2));
              fldst.write(CompileCode, instruction_number);
            }
          return;
        }
      arg1->compile(CompileCode, instruction_number, lhs_rhs, temporary_terms, temporary_terms_idxs, dynamic, steady_dynamic, tef_terms);
      arg2->compile(CompileCode, instruction_number, lhs_rhs, temporary_terms, temporary_terms_idxs, dynamic, steady_dynamic, tef_terms);
      arg3->compile(CompileCode, instruction_number, lhs_rhs, temporary_terms, temporary_terms_idxs, dynamic, steady_dynamic, tef_terms);
      FTRINARY_ ftrinary{static_cast<int>(op_code)};
      ftrinary.write(CompileCode, instruction_number);
    }
    
    bool
    TrinaryOpNode::containsExternalFunction() const
    {
      return arg1->containsExternalFunction()
        || arg2->containsExternalFunction()
        || arg3->containsExternalFunction();
    }
    
    void
    TrinaryOpNode::writeJsonAST(ostream &output) const
    {
      output << R"({"node_type" : "TrinaryOpNode", )"
             << R"("op" : ")";
      switch (op_code)
        {
        case TrinaryOpcode::normcdf:
          output << "normcdf";
          break;
        case TrinaryOpcode::normpdf:
          output << "normpdf";
          break;
        }
      output << R"(", "arg1" : )";
      arg1->writeJsonAST(output);
      output << R"(, "arg2" : )";
      arg2->writeJsonAST(output);
      output << R"(, "arg2" : )";
      arg3->writeJsonAST(output);
      output << "}";
    }
    
    void
    TrinaryOpNode::writeJsonOutput(ostream &output,
                                   const temporary_terms_t &temporary_terms,
                                   const deriv_node_temp_terms_t &tef_terms,
                                   bool isdynamic) const
    {
      // If current node is a temporary term
      if (temporary_terms.find(const_cast<TrinaryOpNode *>(this)) != temporary_terms.end())
        {
          output << "T" << idx;
          return;
        }
    
      switch (op_code)
        {
        case TrinaryOpcode::normcdf:
          output << "normcdf(";
          break;
        case TrinaryOpcode::normpdf:
          output << "normpdf(";
          break;
        }
    
      arg1->writeJsonOutput(output, temporary_terms, tef_terms, isdynamic);
      output << ",";
      arg2->writeJsonOutput(output, temporary_terms, tef_terms, isdynamic);
      output << ",";
      arg3->writeJsonOutput(output, temporary_terms, tef_terms, isdynamic);
      output << ")";
    }
    
    void
    TrinaryOpNode::writeOutput(ostream &output, ExprNodeOutputType output_type,
                               const temporary_terms_t &temporary_terms,
                               const temporary_terms_idxs_t &temporary_terms_idxs,
                               const deriv_node_temp_terms_t &tef_terms) const
    {
      if (checkIfTemporaryTermThenWrite(output, output_type, temporary_terms, temporary_terms_idxs))
        return;
    
      switch (op_code)
        {
        case TrinaryOpcode::normcdf:
          if (isCOutput(output_type))
            {
              // In C, there is no normcdf() primitive, so use erf()
              output << "(0.5*(1+erf(((";
              arg1->writeOutput(output, output_type, temporary_terms, temporary_terms_idxs, tef_terms);
              output << ")-(";
              arg2->writeOutput(output, output_type, temporary_terms, temporary_terms_idxs, tef_terms);
              output << "))/(";
              arg3->writeOutput(output, output_type, temporary_terms, temporary_terms_idxs, tef_terms);
              output << ")/M_SQRT2)))";
            }
          else if (isJuliaOutput(output_type))
    	{
    	  // Julia API is normcdf(mu, sigma, x) !
              output << "normcdf(";
              arg2->writeOutput(output, output_type, temporary_terms, temporary_terms_idxs, tef_terms);
              output << ",";
              arg3->writeOutput(output, output_type, temporary_terms, temporary_terms_idxs, tef_terms);
              output << ",";
              arg1->writeOutput(output, output_type, temporary_terms, temporary_terms_idxs, tef_terms);
              output << ")";
            }
          else
            {
              output << "normcdf(";
              arg1->writeOutput(output, output_type, temporary_terms, temporary_terms_idxs, tef_terms);
              output << ",";
              arg2->writeOutput(output, output_type, temporary_terms, temporary_terms_idxs, tef_terms);
              output << ",";
              arg3->writeOutput(output, output_type, temporary_terms, temporary_terms_idxs, tef_terms);
              output << ")";
            }
          break;
        case TrinaryOpcode::normpdf:
          if (isCOutput(output_type))
            {
              //(1/(v3*sqrt(2*M_PI)*exp(pow((v1-v2)/v3,2)/2)))
              output << "(1/(";
              arg3->writeOutput(output, output_type, temporary_terms, temporary_terms_idxs, tef_terms);
              output << "*sqrt(2*M_PI)*exp(pow((";
              arg1->writeOutput(output, output_type, temporary_terms, temporary_terms_idxs, tef_terms);
              output << "-";
              arg2->writeOutput(output, output_type, temporary_terms, temporary_terms_idxs, tef_terms);
              output << ")/";
              arg3->writeOutput(output, output_type, temporary_terms, temporary_terms_idxs, tef_terms);
              output << ",2)/2)))";
            }
          else if (isJuliaOutput(output_type))
    	{
    	  // Julia API is normpdf(mu, sigma, x) !
              output << "normpdf(";
              arg2->writeOutput(output, output_type, temporary_terms, temporary_terms_idxs, tef_terms);
              output << ",";
              arg3->writeOutput(output, output_type, temporary_terms, temporary_terms_idxs, tef_terms);
              output << ",";
              arg1->writeOutput(output, output_type, temporary_terms, temporary_terms_idxs, tef_terms);
              output << ")";
            }
          else
            {
              output << "normpdf(";
              arg1->writeOutput(output, output_type, temporary_terms, temporary_terms_idxs, tef_terms);
              output << ",";
              arg2->writeOutput(output, output_type, temporary_terms, temporary_terms_idxs, tef_terms);
              output << ",";
              arg3->writeOutput(output, output_type, temporary_terms, temporary_terms_idxs, tef_terms);
              output << ")";
            }
          break;
        }
    }
    
    void
    TrinaryOpNode::writeExternalFunctionOutput(ostream &output, ExprNodeOutputType output_type,
                                               const temporary_terms_t &temporary_terms,
                                               const temporary_terms_idxs_t &temporary_terms_idxs,
                                               deriv_node_temp_terms_t &tef_terms) const
    {
      arg1->writeExternalFunctionOutput(output, output_type, temporary_terms, temporary_terms_idxs, tef_terms);
      arg2->writeExternalFunctionOutput(output, output_type, temporary_terms, temporary_terms_idxs, tef_terms);
      arg3->writeExternalFunctionOutput(output, output_type, temporary_terms, temporary_terms_idxs, tef_terms);
    }
    
    void
    TrinaryOpNode::writeJsonExternalFunctionOutput(vector<string> &efout,
                                                   const temporary_terms_t &temporary_terms,
                                                   deriv_node_temp_terms_t &tef_terms,
                                                   bool isdynamic) const
    {
      arg1->writeJsonExternalFunctionOutput(efout, temporary_terms, tef_terms, isdynamic);
      arg2->writeJsonExternalFunctionOutput(efout, temporary_terms, tef_terms, isdynamic);
      arg3->writeJsonExternalFunctionOutput(efout, temporary_terms, tef_terms, isdynamic);
    }
    
    void
    TrinaryOpNode::compileExternalFunctionOutput(ostream &CompileCode, unsigned int &instruction_number,
                                                 bool lhs_rhs, const temporary_terms_t &temporary_terms,
                                                 const temporary_terms_idxs_t &temporary_terms_idxs, bool dynamic, bool steady_dynamic,
                                                 deriv_node_temp_terms_t &tef_terms) const
    {
      arg1->compileExternalFunctionOutput(CompileCode, instruction_number, lhs_rhs, temporary_terms,
                                          temporary_terms_idxs, dynamic, steady_dynamic, tef_terms);
      arg2->compileExternalFunctionOutput(CompileCode, instruction_number, lhs_rhs, temporary_terms,
                                          temporary_terms_idxs, dynamic, steady_dynamic, tef_terms);
      arg3->compileExternalFunctionOutput(CompileCode, instruction_number, lhs_rhs, temporary_terms,
                                          temporary_terms_idxs, dynamic, steady_dynamic, tef_terms);
    }
    
    void
    TrinaryOpNode::collectVARLHSVariable(set<expr_t> &result) const
    {
      cerr << "ERROR: you can only have variables or unary ops on LHS of VAR" << endl;
      exit(EXIT_FAILURE);
    }
    
    void
    TrinaryOpNode::collectDynamicVariables(SymbolType type_arg, set<pair<int, int>> &result) const
    {
      arg1->collectDynamicVariables(type_arg, result);
      arg2->collectDynamicVariables(type_arg, result);
      arg3->collectDynamicVariables(type_arg, result);
    }
    
    void
    TrinaryOpNode::computeSubExprContainingVariable(int symb_id, int lag, set<expr_t> &contain_var) const
    {
      arg1->computeSubExprContainingVariable(symb_id, lag, contain_var);
      arg2->computeSubExprContainingVariable(symb_id, lag, contain_var);
      arg3->computeSubExprContainingVariable(symb_id, lag, contain_var);
      if (contain_var.count(arg1) > 0 || contain_var.count(arg2) > 0 || contain_var.count(arg3) > 0)
        contain_var.insert(const_cast<TrinaryOpNode *>(this));
    }
    
    BinaryOpNode *
    TrinaryOpNode::normalizeEquationHelper(const set<expr_t> &contain_var, expr_t rhs) const
    {
      throw NormalizationFailed();
    }
    
    expr_t
    TrinaryOpNode::getChainRuleDerivative(int deriv_id, const map<int, BinaryOpNode *> &recursive_variables)
    {
      expr_t darg1 = arg1->getChainRuleDerivative(deriv_id, recursive_variables);
      expr_t darg2 = arg2->getChainRuleDerivative(deriv_id, recursive_variables);
      expr_t darg3 = arg3->getChainRuleDerivative(deriv_id, recursive_variables);
      return composeDerivatives(darg1, darg2, darg3);
    }
    
    expr_t
    TrinaryOpNode::buildSimilarTrinaryOpNode(expr_t alt_arg1, expr_t alt_arg2, expr_t alt_arg3, DataTree &alt_datatree) const
    {
      switch (op_code)
        {
        case TrinaryOpcode::normcdf:
          return alt_datatree.AddNormcdf(alt_arg1, alt_arg2, alt_arg3);
        case TrinaryOpcode::normpdf:
          return alt_datatree.AddNormpdf(alt_arg1, alt_arg2, alt_arg3);
        }
      // Suppress GCC warning
      exit(EXIT_FAILURE);
    }
    
    expr_t
    TrinaryOpNode::toStatic(DataTree &static_datatree) const
    {
      expr_t sarg1 = arg1->toStatic(static_datatree);
      expr_t sarg2 = arg2->toStatic(static_datatree);
      expr_t sarg3 = arg3->toStatic(static_datatree);
      return buildSimilarTrinaryOpNode(sarg1, sarg2, sarg3, static_datatree);
    }
    
    void
    TrinaryOpNode::computeXrefs(EquationInfo &ei) const
    {
      arg1->computeXrefs(ei);
      arg2->computeXrefs(ei);
      arg3->computeXrefs(ei);
    }
    
    expr_t
    TrinaryOpNode::clone(DataTree &datatree) const
    {
      expr_t substarg1 = arg1->clone(datatree);
      expr_t substarg2 = arg2->clone(datatree);
      expr_t substarg3 = arg3->clone(datatree);
      return buildSimilarTrinaryOpNode(substarg1, substarg2, substarg3, datatree);
    }
    
    int
    TrinaryOpNode::maxEndoLead() const
    {
      return max(arg1->maxEndoLead(), max(arg2->maxEndoLead(), arg3->maxEndoLead()));
    }
    
    int
    TrinaryOpNode::maxExoLead() const
    {
      return max(arg1->maxExoLead(), max(arg2->maxExoLead(), arg3->maxExoLead()));
    }
    
    int
    TrinaryOpNode::maxEndoLag() const
    {
      return max(arg1->maxEndoLag(), max(arg2->maxEndoLag(), arg3->maxEndoLag()));
    }
    
    int
    TrinaryOpNode::maxExoLag() const
    {
      return max(arg1->maxExoLag(), max(arg2->maxExoLag(), arg3->maxExoLag()));
    }
    
    int
    TrinaryOpNode::maxLead() const
    {
      return max(arg1->maxLead(), max(arg2->maxLead(), arg3->maxLead()));
    }
    
    int
    TrinaryOpNode::maxLag() const
    {
      return max(arg1->maxLag(), max(arg2->maxLag(), arg3->maxLag()));
    }
    
    int
    TrinaryOpNode::maxLagWithDiffsExpanded() const
    {
      return max(arg1->maxLagWithDiffsExpanded(),
                 max(arg2->maxLagWithDiffsExpanded(), arg3->maxLagWithDiffsExpanded()));
    }
    
    expr_t
    TrinaryOpNode::undiff() const
    {
      expr_t arg1subst = arg1->undiff();
      expr_t arg2subst = arg2->undiff();
      expr_t arg3subst = arg3->undiff();
      return buildSimilarTrinaryOpNode(arg1subst, arg2subst, arg3subst, datatree);
    }
    
    int
    TrinaryOpNode::VarMaxLag(const set<expr_t> &lhs_lag_equiv) const
    {
      return max(arg1->VarMaxLag(lhs_lag_equiv),
                 max(arg2->VarMaxLag(lhs_lag_equiv),
                     arg3->VarMaxLag(lhs_lag_equiv)));
    }
    
    expr_t
    TrinaryOpNode::decreaseLeadsLags(int n) const
    {
      expr_t arg1subst = arg1->decreaseLeadsLags(n);
      expr_t arg2subst = arg2->decreaseLeadsLags(n);
      expr_t arg3subst = arg3->decreaseLeadsLags(n);
      return buildSimilarTrinaryOpNode(arg1subst, arg2subst, arg3subst, datatree);
    }
    
    expr_t
    TrinaryOpNode::decreaseLeadsLagsPredeterminedVariables() const
    {
      expr_t arg1subst = arg1->decreaseLeadsLagsPredeterminedVariables();
      expr_t arg2subst = arg2->decreaseLeadsLagsPredeterminedVariables();
      expr_t arg3subst = arg3->decreaseLeadsLagsPredeterminedVariables();
      return buildSimilarTrinaryOpNode(arg1subst, arg2subst, arg3subst, datatree);
    }
    
    expr_t
    TrinaryOpNode::substituteEndoLeadGreaterThanTwo(subst_table_t &subst_table, vector<BinaryOpNode *> &neweqs, bool deterministic_model) const
    {
      if (maxEndoLead() < 2)
        return const_cast<TrinaryOpNode *>(this);
      else if (deterministic_model)
        {
          expr_t arg1subst = arg1->substituteEndoLeadGreaterThanTwo(subst_table, neweqs, deterministic_model);
          expr_t arg2subst = arg2->substituteEndoLeadGreaterThanTwo(subst_table, neweqs, deterministic_model);
          expr_t arg3subst = arg3->substituteEndoLeadGreaterThanTwo(subst_table, neweqs, deterministic_model);
          return buildSimilarTrinaryOpNode(arg1subst, arg2subst, arg3subst, datatree);
        }
      else
        return createEndoLeadAuxiliaryVarForMyself(subst_table, neweqs);
    }
    
    expr_t
    TrinaryOpNode::substituteEndoLagGreaterThanTwo(subst_table_t &subst_table, vector<BinaryOpNode *> &neweqs) const
    {
      expr_t arg1subst = arg1->substituteEndoLagGreaterThanTwo(subst_table, neweqs);
      expr_t arg2subst = arg2->substituteEndoLagGreaterThanTwo(subst_table, neweqs);
      expr_t arg3subst = arg3->substituteEndoLagGreaterThanTwo(subst_table, neweqs);
      return buildSimilarTrinaryOpNode(arg1subst, arg2subst, arg3subst, datatree);
    }
    
    expr_t
    TrinaryOpNode::substituteExoLead(subst_table_t &subst_table, vector<BinaryOpNode *> &neweqs, bool deterministic_model) const
    {
      if (maxExoLead() == 0)
        return const_cast<TrinaryOpNode *>(this);
      else if (deterministic_model)
        {
          expr_t arg1subst = arg1->substituteExoLead(subst_table, neweqs, deterministic_model);
          expr_t arg2subst = arg2->substituteExoLead(subst_table, neweqs, deterministic_model);
          expr_t arg3subst = arg3->substituteExoLead(subst_table, neweqs, deterministic_model);
          return buildSimilarTrinaryOpNode(arg1subst, arg2subst, arg3subst, datatree);
        }
      else
        return createExoLeadAuxiliaryVarForMyself(subst_table, neweqs);
    }
    
    expr_t
    TrinaryOpNode::substituteExoLag(subst_table_t &subst_table, vector<BinaryOpNode *> &neweqs) const
    {
      expr_t arg1subst = arg1->substituteExoLag(subst_table, neweqs);
      expr_t arg2subst = arg2->substituteExoLag(subst_table, neweqs);
      expr_t arg3subst = arg3->substituteExoLag(subst_table, neweqs);
      return buildSimilarTrinaryOpNode(arg1subst, arg2subst, arg3subst, datatree);
    }
    
    expr_t
    TrinaryOpNode::substituteExpectation(subst_table_t &subst_table, vector<BinaryOpNode *> &neweqs, bool partial_information_model) const
    {
      expr_t arg1subst = arg1->substituteExpectation(subst_table, neweqs, partial_information_model);
      expr_t arg2subst = arg2->substituteExpectation(subst_table, neweqs, partial_information_model);
      expr_t arg3subst = arg3->substituteExpectation(subst_table, neweqs, partial_information_model);
      return buildSimilarTrinaryOpNode(arg1subst, arg2subst, arg3subst, datatree);
    }
    
    expr_t
    TrinaryOpNode::substituteAdl() const
    {
      expr_t arg1subst = arg1->substituteAdl();
      expr_t arg2subst = arg2->substituteAdl();
      expr_t arg3subst = arg3->substituteAdl();
      return buildSimilarTrinaryOpNode(arg1subst, arg2subst, arg3subst, datatree);
    }
    
    expr_t
    TrinaryOpNode::substituteModelLocalVariables() const
    {
      expr_t arg1subst = arg1->substituteModelLocalVariables();
      expr_t arg2subst = arg2->substituteModelLocalVariables();
      expr_t arg3subst = arg3->substituteModelLocalVariables();
      return buildSimilarTrinaryOpNode(arg1subst, arg2subst, arg3subst, datatree);
    }
    
    expr_t
    TrinaryOpNode::substituteVarExpectation(const map<string, expr_t> &subst_table) const
    {
      expr_t arg1subst = arg1->substituteVarExpectation(subst_table);
      expr_t arg2subst = arg2->substituteVarExpectation(subst_table);
      expr_t arg3subst = arg3->substituteVarExpectation(subst_table);
      return buildSimilarTrinaryOpNode(arg1subst, arg2subst, arg3subst, datatree);
    }
    
    void
    TrinaryOpNode::findDiffNodes(lag_equivalence_table_t &nodes) const
    {
      arg1->findDiffNodes(nodes);
      arg2->findDiffNodes(nodes);
      arg3->findDiffNodes(nodes);
    }
    
    void
    TrinaryOpNode::findUnaryOpNodesForAuxVarCreation(lag_equivalence_table_t &nodes) const
    {
      arg1->findUnaryOpNodesForAuxVarCreation(nodes);
      arg2->findUnaryOpNodesForAuxVarCreation(nodes);
      arg3->findUnaryOpNodesForAuxVarCreation(nodes);
    }
    
    int
    TrinaryOpNode::findTargetVariable(int lhs_symb_id) const
    {
      int retval = arg1->findTargetVariable(lhs_symb_id);
      if (retval < 0)
        retval = arg2->findTargetVariable(lhs_symb_id);
      if (retval < 0)
        retval = arg3->findTargetVariable(lhs_symb_id);
      return retval;
    }
    
    expr_t
    TrinaryOpNode::substituteDiff(const lag_equivalence_table_t &nodes, subst_table_t &subst_table,
                                  vector<BinaryOpNode *> &neweqs) const
    {
      expr_t arg1subst = arg1->substituteDiff(nodes, subst_table, neweqs);
      expr_t arg2subst = arg2->substituteDiff(nodes, subst_table, neweqs);
      expr_t arg3subst = arg3->substituteDiff(nodes, subst_table, neweqs);
      return buildSimilarTrinaryOpNode(arg1subst, arg2subst, arg3subst, datatree);
    }
    
    expr_t
    TrinaryOpNode::substituteUnaryOpNodes(const lag_equivalence_table_t &nodes, subst_table_t &subst_table, vector<BinaryOpNode *> &neweqs) const
    {
      expr_t arg1subst = arg1->substituteUnaryOpNodes(nodes, subst_table, neweqs);
      expr_t arg2subst = arg2->substituteUnaryOpNodes(nodes, subst_table, neweqs);
      expr_t arg3subst = arg3->substituteUnaryOpNodes(nodes, subst_table, neweqs);
      return buildSimilarTrinaryOpNode(arg1subst, arg2subst, arg3subst, datatree);
    }
    
    int
    TrinaryOpNode::countDiffs() const
    {
      return max(arg1->countDiffs(), max(arg2->countDiffs(), arg3->countDiffs()));
    }
    
    expr_t
    TrinaryOpNode::substitutePacExpectation(const string &name, expr_t subexpr)
    {
      expr_t arg1subst = arg1->substitutePacExpectation(name, subexpr);
      expr_t arg2subst = arg2->substitutePacExpectation(name, subexpr);
      expr_t arg3subst = arg3->substitutePacExpectation(name, subexpr);
      return buildSimilarTrinaryOpNode(arg1subst, arg2subst, arg3subst, datatree);
    }
    
    expr_t
    TrinaryOpNode::substitutePacTargetNonstationary(const string &name, expr_t subexpr)
    {
      expr_t arg1subst = arg1->substitutePacTargetNonstationary(name, subexpr);
      expr_t arg2subst = arg2->substitutePacTargetNonstationary(name, subexpr);
      expr_t arg3subst = arg3->substitutePacTargetNonstationary(name, subexpr);
      return buildSimilarTrinaryOpNode(arg1subst, arg2subst, arg3subst, datatree);
    }
    
    expr_t
    TrinaryOpNode::differentiateForwardVars(const vector<string> &subset, subst_table_t &subst_table, vector<BinaryOpNode *> &neweqs) const
    {
      expr_t arg1subst = arg1->differentiateForwardVars(subset, subst_table, neweqs);
      expr_t arg2subst = arg2->differentiateForwardVars(subset, subst_table, neweqs);
      expr_t arg3subst = arg3->differentiateForwardVars(subset, subst_table, neweqs);
      return buildSimilarTrinaryOpNode(arg1subst, arg2subst, arg3subst, datatree);
    }
    
    bool
    TrinaryOpNode::isNumConstNodeEqualTo(double value) const
    {
      return false;
    }
    
    bool
    TrinaryOpNode::isVariableNodeEqualTo(SymbolType type_arg, int variable_id, int lag_arg) const
    {
      return false;
    }
    
    bool
    TrinaryOpNode::containsPacExpectation(const string &pac_model_name) const
    {
      return (arg1->containsPacExpectation(pac_model_name) || arg2->containsPacExpectation(pac_model_name) || arg3->containsPacExpectation(pac_model_name));
    }
    
    bool
    TrinaryOpNode::containsPacTargetNonstationary(const string &pac_model_name) const
    {
      return arg1->containsPacTargetNonstationary(pac_model_name)
        || arg2->containsPacTargetNonstationary(pac_model_name)
        || arg3->containsPacTargetNonstationary(pac_model_name);
    }
    
    expr_t
    TrinaryOpNode::replaceTrendVar() const
    {
      expr_t arg1subst = arg1->replaceTrendVar();
      expr_t arg2subst = arg2->replaceTrendVar();
      expr_t arg3subst = arg3->replaceTrendVar();
      return buildSimilarTrinaryOpNode(arg1subst, arg2subst, arg3subst, datatree);
    }
    
    expr_t
    TrinaryOpNode::detrend(int symb_id, bool log_trend, expr_t trend) const
    {
      expr_t arg1subst = arg1->detrend(symb_id, log_trend, trend);
      expr_t arg2subst = arg2->detrend(symb_id, log_trend, trend);
      expr_t arg3subst = arg3->detrend(symb_id, log_trend, trend);
      return buildSimilarTrinaryOpNode(arg1subst, arg2subst, arg3subst, datatree);
    }
    
    expr_t
    TrinaryOpNode::removeTrendLeadLag(const map<int, expr_t> &trend_symbols_map) const
    {
      expr_t arg1subst = arg1->removeTrendLeadLag(trend_symbols_map);
      expr_t arg2subst = arg2->removeTrendLeadLag(trend_symbols_map);
      expr_t arg3subst = arg3->removeTrendLeadLag(trend_symbols_map);
      return buildSimilarTrinaryOpNode(arg1subst, arg2subst, arg3subst, datatree);
    }
    
    bool
    TrinaryOpNode::isInStaticForm() const
    {
      return arg1->isInStaticForm() && arg2->isInStaticForm() && arg3->isInStaticForm();
    }
    
    bool
    TrinaryOpNode::isParamTimesEndogExpr() const
    {
      return arg1->isParamTimesEndogExpr()
        || arg2->isParamTimesEndogExpr()
        || arg3->isParamTimesEndogExpr();
    }
    
    expr_t
    TrinaryOpNode::substituteStaticAuxiliaryVariable() const
    {
      expr_t arg1subst = arg1->substituteStaticAuxiliaryVariable();
      expr_t arg2subst = arg2->substituteStaticAuxiliaryVariable();
      expr_t arg3subst = arg3->substituteStaticAuxiliaryVariable();
      return buildSimilarTrinaryOpNode(arg1subst, arg2subst, arg3subst, datatree);
    }
    
    expr_t
    TrinaryOpNode::replaceVarsInEquation(map<VariableNode *, NumConstNode *> &table) const
    {
      expr_t arg1subst = arg1->replaceVarsInEquation(table);
      expr_t arg2subst = arg2->replaceVarsInEquation(table);
      expr_t arg3subst = arg3->replaceVarsInEquation(table);
      return buildSimilarTrinaryOpNode(arg1subst, arg2subst, arg3subst, datatree);
    }
    
    AbstractExternalFunctionNode::AbstractExternalFunctionNode(DataTree &datatree_arg,
                                                               int idx_arg,
                                                               int symb_id_arg,
                                                               vector<expr_t> arguments_arg) :
      ExprNode{datatree_arg, idx_arg},
      symb_id{symb_id_arg},
      arguments{move(arguments_arg)}
    {
    }
    
    void
    AbstractExternalFunctionNode::prepareForDerivation()
    {
      if (preparedForDerivation)
        return;
    
      for (auto argument : arguments)
        argument->prepareForDerivation();
    
      non_null_derivatives = arguments.at(0)->non_null_derivatives;
      for (int i = 1; i < static_cast<int>(arguments.size()); i++)
        set_union(non_null_derivatives.begin(),
                  non_null_derivatives.end(),
                  arguments.at(i)->non_null_derivatives.begin(),
                  arguments.at(i)->non_null_derivatives.end(),
                  inserter(non_null_derivatives, non_null_derivatives.begin()));
    
      preparedForDerivation = true;
    }
    
    expr_t
    AbstractExternalFunctionNode::computeDerivative(int deriv_id)
    {
      assert(datatree.external_functions_table.getNargs(symb_id) > 0);
      vector<expr_t> dargs;
      for (auto argument : arguments)
        dargs.push_back(argument->getDerivative(deriv_id));
      return composeDerivatives(dargs);
    }
    
    expr_t
    AbstractExternalFunctionNode::getChainRuleDerivative(int deriv_id, const map<int, BinaryOpNode *> &recursive_variables)
    {
      assert(datatree.external_functions_table.getNargs(symb_id) > 0);
      vector<expr_t> dargs;
      for (auto argument : arguments)
        dargs.push_back(argument->getChainRuleDerivative(deriv_id, recursive_variables));
      return composeDerivatives(dargs);
    }
    
    unsigned int
    AbstractExternalFunctionNode::compileExternalFunctionArguments(ostream &CompileCode, unsigned int &instruction_number,
                                                                   bool lhs_rhs, const temporary_terms_t &temporary_terms,
                                                                   const temporary_terms_idxs_t &temporary_terms_idxs, bool dynamic, bool steady_dynamic,
                                                                   const deriv_node_temp_terms_t &tef_terms) const
    {
      for (auto argument : arguments)
        argument->compile(CompileCode, instruction_number, lhs_rhs, temporary_terms,
                          temporary_terms_idxs, dynamic, steady_dynamic, tef_terms);
      return (arguments.size());
    }
    
    void
    AbstractExternalFunctionNode::collectVARLHSVariable(set<expr_t> &result) const
    {
      cerr << "ERROR: you can only have variables or unary ops on LHS of VAR" << endl;
      exit(EXIT_FAILURE);
    }
    
    void
    AbstractExternalFunctionNode::collectDynamicVariables(SymbolType type_arg, set<pair<int, int>> &result) const
    {
      for (auto argument : arguments)
        argument->collectDynamicVariables(type_arg, result);
    }
    
    double
    AbstractExternalFunctionNode::eval(const eval_context_t &eval_context) const noexcept(false)
    {
      throw EvalExternalFunctionException();
    }
    
    int
    AbstractExternalFunctionNode::maxEndoLead() const
    {
      int val = 0;
      for (auto argument : arguments)
        val = max(val, argument->maxEndoLead());
      return val;
    }
    
    int
    AbstractExternalFunctionNode::maxExoLead() const
    {
      int val = 0;
      for (auto argument : arguments)
        val = max(val, argument->maxExoLead());
      return val;
    }
    
    int
    AbstractExternalFunctionNode::maxEndoLag() const
    {
      int val = 0;
      for (auto argument : arguments)
        val = max(val, argument->maxEndoLag());
      return val;
    }
    
    int
    AbstractExternalFunctionNode::maxExoLag() const
    {
      int val = 0;
      for (auto argument : arguments)
        val = max(val, argument->maxExoLag());
      return val;
    }
    
    int
    AbstractExternalFunctionNode::maxLead() const
    {
      int val = 0;
      for (auto argument : arguments)
        val = max(val, argument->maxLead());
      return val;
    }
    
    int
    AbstractExternalFunctionNode::maxLag() const
    {
      int val = 0;
      for (auto argument : arguments)
        val = max(val, argument->maxLag());
      return val;
    }
    
    int
    AbstractExternalFunctionNode::maxLagWithDiffsExpanded() const
    {
      int val = 0;
      for (auto argument : arguments)
        val = max(val, argument->maxLagWithDiffsExpanded());
      return val;
    }
    
    expr_t
    AbstractExternalFunctionNode::undiff() const
    {
      vector<expr_t> arguments_subst;
      for (auto argument : arguments)
        arguments_subst.push_back(argument->undiff());
      return buildSimilarExternalFunctionNode(arguments_subst, datatree);
    }
    
    int
    AbstractExternalFunctionNode::VarMaxLag(const set<expr_t> &lhs_lag_equiv) const
    {
      int max_lag = 0;
      for (auto argument : arguments)
        max_lag = max(max_lag, argument->VarMaxLag(lhs_lag_equiv));
      return max_lag;
    }
    
    expr_t
    AbstractExternalFunctionNode::decreaseLeadsLags(int n) const
    {
      vector<expr_t> arguments_subst;
      for (auto argument : arguments)
        arguments_subst.push_back(argument->decreaseLeadsLags(n));
      return buildSimilarExternalFunctionNode(arguments_subst, datatree);
    }
    
    expr_t
    AbstractExternalFunctionNode::decreaseLeadsLagsPredeterminedVariables() const
    {
      vector<expr_t> arguments_subst;
      for (auto argument : arguments)
        arguments_subst.push_back(argument->decreaseLeadsLagsPredeterminedVariables());
      return buildSimilarExternalFunctionNode(arguments_subst, datatree);
    }
    
    expr_t
    AbstractExternalFunctionNode::substituteEndoLeadGreaterThanTwo(subst_table_t &subst_table, vector<BinaryOpNode *> &neweqs, bool deterministic_model) const
    {
      vector<expr_t> arguments_subst;
      for (auto argument : arguments)
        arguments_subst.push_back(argument->substituteEndoLeadGreaterThanTwo(subst_table, neweqs, deterministic_model));
      return buildSimilarExternalFunctionNode(arguments_subst, datatree);
    }
    
    expr_t
    AbstractExternalFunctionNode::substituteEndoLagGreaterThanTwo(subst_table_t &subst_table, vector<BinaryOpNode *> &neweqs) const
    {
      vector<expr_t> arguments_subst;
      for (auto argument : arguments)
        arguments_subst.push_back(argument->substituteEndoLagGreaterThanTwo(subst_table, neweqs));
      return buildSimilarExternalFunctionNode(arguments_subst, datatree);
    }
    
    expr_t
    AbstractExternalFunctionNode::substituteExoLead(subst_table_t &subst_table, vector<BinaryOpNode *> &neweqs, bool deterministic_model) const
    {
      vector<expr_t> arguments_subst;
      for (auto argument : arguments)
        arguments_subst.push_back(argument->substituteExoLead(subst_table, neweqs, deterministic_model));
      return buildSimilarExternalFunctionNode(arguments_subst, datatree);
    }
    
    expr_t
    AbstractExternalFunctionNode::substituteExoLag(subst_table_t &subst_table, vector<BinaryOpNode *> &neweqs) const
    {
      vector<expr_t> arguments_subst;
      for (auto argument : arguments)
        arguments_subst.push_back(argument->substituteExoLag(subst_table, neweqs));
      return buildSimilarExternalFunctionNode(arguments_subst, datatree);
    }
    
    expr_t
    AbstractExternalFunctionNode::substituteExpectation(subst_table_t &subst_table, vector<BinaryOpNode *> &neweqs, bool partial_information_model) const
    {
      vector<expr_t> arguments_subst;
      for (auto argument : arguments)
        arguments_subst.push_back(argument->substituteExpectation(subst_table, neweqs, partial_information_model));
      return buildSimilarExternalFunctionNode(arguments_subst, datatree);
    }
    
    expr_t
    AbstractExternalFunctionNode::substituteAdl() const
    {
      vector<expr_t> arguments_subst;
      for (auto argument : arguments)
        arguments_subst.push_back(argument->substituteAdl());
      return buildSimilarExternalFunctionNode(arguments_subst, datatree);
    }
    
    expr_t
    AbstractExternalFunctionNode::substituteModelLocalVariables() const
    {
      vector<expr_t> arguments_subst;
      for (auto argument : arguments)
        arguments_subst.push_back(argument->substituteModelLocalVariables());
      return buildSimilarExternalFunctionNode(arguments_subst, datatree);
    }
    
    expr_t
    AbstractExternalFunctionNode::substituteVarExpectation(const map<string, expr_t> &subst_table) const
    {
      vector<expr_t> arguments_subst;
      for (auto argument : arguments)
        arguments_subst.push_back(argument->substituteVarExpectation(subst_table));
      return buildSimilarExternalFunctionNode(arguments_subst, datatree);
    }
    
    void
    AbstractExternalFunctionNode::findDiffNodes(lag_equivalence_table_t &nodes) const
    {
      for (auto argument : arguments)
        argument->findDiffNodes(nodes);
    }
    
    void
    AbstractExternalFunctionNode::findUnaryOpNodesForAuxVarCreation(lag_equivalence_table_t &nodes) const
    {
      for (auto argument : arguments)
        argument->findUnaryOpNodesForAuxVarCreation(nodes);
    }
    
    int
    AbstractExternalFunctionNode::findTargetVariable(int lhs_symb_id) const
    {
      for (auto argument : arguments)
        if (int retval = argument->findTargetVariable(lhs_symb_id);
            retval >= 0)
          return retval;
      return -1;
    }
    
    expr_t
    AbstractExternalFunctionNode::substituteDiff(const lag_equivalence_table_t &nodes, subst_table_t &subst_table,
                                                 vector<BinaryOpNode *> &neweqs) const
    {
      vector<expr_t> arguments_subst;
      for (auto argument : arguments)
        arguments_subst.push_back(argument->substituteDiff(nodes, subst_table, neweqs));
      return buildSimilarExternalFunctionNode(arguments_subst, datatree);
    }
    
    expr_t
    AbstractExternalFunctionNode::substituteUnaryOpNodes(const lag_equivalence_table_t &nodes, subst_table_t &subst_table, vector<BinaryOpNode *> &neweqs) const
    {
      vector<expr_t> arguments_subst;
      for (auto argument : arguments)
        arguments_subst.push_back(argument->substituteUnaryOpNodes(nodes, subst_table, neweqs));
      return buildSimilarExternalFunctionNode(arguments_subst, datatree);
    }
    
    int
    AbstractExternalFunctionNode::countDiffs() const
    {
      int ndiffs = 0;
      for (auto argument : arguments)
        ndiffs = max(ndiffs, argument->countDiffs());
      return ndiffs;
    }
    
    expr_t
    AbstractExternalFunctionNode::substitutePacExpectation(const string &name, expr_t subexpr)
    {
      vector<expr_t> arguments_subst;
      for (auto argument : arguments)
        arguments_subst.push_back(argument->substitutePacExpectation(name, subexpr));
      return buildSimilarExternalFunctionNode(arguments_subst, datatree);
    }
    
    expr_t
    AbstractExternalFunctionNode::substitutePacTargetNonstationary(const string &name, expr_t subexpr)
    {
      vector<expr_t> arguments_subst;
      for (auto argument : arguments)
        arguments_subst.push_back(argument->substitutePacTargetNonstationary(name, subexpr));
      return buildSimilarExternalFunctionNode(arguments_subst, datatree);
    }
    
    expr_t
    AbstractExternalFunctionNode::differentiateForwardVars(const vector<string> &subset, subst_table_t &subst_table, vector<BinaryOpNode *> &neweqs) const
    {
      vector<expr_t> arguments_subst;
      for (auto argument : arguments)
        arguments_subst.push_back(argument->differentiateForwardVars(subset, subst_table, neweqs));
      return buildSimilarExternalFunctionNode(arguments_subst, datatree);
    }
    
    bool
    AbstractExternalFunctionNode::alreadyWrittenAsTefTerm(int the_symb_id, const deriv_node_temp_terms_t &tef_terms) const
    {
      if (tef_terms.find({ the_symb_id, arguments }) != tef_terms.end())
        return true;
      return false;
    }
    
    int
    AbstractExternalFunctionNode::getIndxInTefTerms(int the_symb_id, const deriv_node_temp_terms_t &tef_terms) const noexcept(false)
    {
      if (auto it = tef_terms.find({ the_symb_id, arguments });
          it != tef_terms.end())
        return it->second;
      throw UnknownFunctionNameAndArgs();
    }
    
    void
    AbstractExternalFunctionNode::computeTemporaryTerms(const pair<int, int> &derivOrder,
                                                        map<pair<int, int>, temporary_terms_t> &temp_terms_map,
                                                        map<expr_t, pair<int, pair<int, int>>> &reference_count,
                                                        bool is_matlab) const
    {
      /* All external function nodes are declared as temporary terms.
    
         Given that temporary terms are separated in several functions (residuals,
         jacobian, …), we must make sure that all temporary terms derived from a
         given external function call are assigned just after that call.
    
         As a consequence, we need to “promote” some terms to a previous level (in
         the sense that residuals come before jacobian), if a temporary term
         corresponding to the same external function call is present in that
         previous level. */
    
      expr_t this2 = const_cast<AbstractExternalFunctionNode *>(this);
      for (auto &tt : temp_terms_map)
        if (auto it = find_if(tt.second.cbegin(), tt.second.cend(), sameTefTermPredicate());
            it != tt.second.cend())
          {
            tt.second.insert(this2);
            return;
          }
    
      temp_terms_map[derivOrder].insert(this2);
    }
    
    void
    AbstractExternalFunctionNode::computeBlockTemporaryTerms(int blk, int eq, vector<vector<temporary_terms_t>> &blocks_temporary_terms,
                                                             map<expr_t, tuple<int, int, int>> &reference_count) const
    {
      // See comments in computeTemporaryTerms() for the logic
      expr_t this2 = const_cast<AbstractExternalFunctionNode *>(this);
      for (auto &btt : blocks_temporary_terms)
        for (auto &tt : btt)
          if (auto it = find_if(tt.cbegin(), tt.cend(), sameTefTermPredicate());
              it != tt.cend())
            {
              tt.insert(this2);
              return;
            }
    
      blocks_temporary_terms[blk][eq].insert(this2);
    }
    
    bool
    AbstractExternalFunctionNode::isNumConstNodeEqualTo(double value) const
    {
      return false;
    }
    
    bool
    AbstractExternalFunctionNode::isVariableNodeEqualTo(SymbolType type_arg, int variable_id, int lag_arg) const
    {
      return false;
    }
    
    bool
    AbstractExternalFunctionNode::containsPacExpectation(const string &pac_model_name) const
    {
      for (auto argument : arguments)
        if (argument->containsPacExpectation(pac_model_name))
          return true;
      return false;
    }
    
    bool
    AbstractExternalFunctionNode::containsPacTargetNonstationary(const string &pac_model_name) const
    {
      for (auto argument : arguments)
        if (argument->containsPacTargetNonstationary(pac_model_name))
          return true;
      return false;
    }
    
    expr_t
    AbstractExternalFunctionNode::replaceTrendVar() const
    {
      vector<expr_t> arguments_subst;
      for (auto argument : arguments)
        arguments_subst.push_back(argument->replaceTrendVar());
      return buildSimilarExternalFunctionNode(arguments_subst, datatree);
    }
    
    expr_t
    AbstractExternalFunctionNode::detrend(int symb_id, bool log_trend, expr_t trend) const
    {
      vector<expr_t> arguments_subst;
      for (auto argument : arguments)
        arguments_subst.push_back(argument->detrend(symb_id, log_trend, trend));
      return buildSimilarExternalFunctionNode(arguments_subst, datatree);
    }
    
    expr_t
    AbstractExternalFunctionNode::removeTrendLeadLag(const map<int, expr_t> &trend_symbols_map) const
    {
      vector<expr_t> arguments_subst;
      for (auto argument : arguments)
        arguments_subst.push_back(argument->removeTrendLeadLag(trend_symbols_map));
      return buildSimilarExternalFunctionNode(arguments_subst, datatree);
    }
    
    bool
    AbstractExternalFunctionNode::isInStaticForm() const
    {
      for (auto argument : arguments)
        if (!argument->isInStaticForm())
          return false;
      return true;
    }
    
    bool
    AbstractExternalFunctionNode::isParamTimesEndogExpr() const
    {
      return false;
    }
    
    void
    AbstractExternalFunctionNode::computeSubExprContainingVariable(int symb_id, int lag, set<expr_t> &contain_var) const
    {
      bool var_present = false;
      for (auto arg : arguments)
        {
          arg->computeSubExprContainingVariable(symb_id, lag, contain_var);
          var_present = var_present || contain_var.count(arg) > 0;
        }
      if (var_present)
        contain_var.insert(const_cast<AbstractExternalFunctionNode *>(this));
    }
    
    BinaryOpNode *
    AbstractExternalFunctionNode::normalizeEquationHelper(const set<expr_t> &contain_var, expr_t rhs) const
    {
      throw NormalizationFailed();
    }
    
    void
    AbstractExternalFunctionNode::writeExternalFunctionArguments(ostream &output, ExprNodeOutputType output_type,
                                                                 const temporary_terms_t &temporary_terms,
                                                                 const temporary_terms_idxs_t &temporary_terms_idxs,
                                                                 const deriv_node_temp_terms_t &tef_terms) const
    {
      for (auto it = arguments.begin(); it != arguments.end(); ++it)
        {
          if (it != arguments.begin())
            output << ",";
    
          (*it)->writeOutput(output, output_type, temporary_terms, temporary_terms_idxs, tef_terms);
        }
    }
    
    void
    AbstractExternalFunctionNode::writeJsonASTExternalFunctionArguments(ostream &output) const
    {
      int i = 0;
      output << "{";
      for (auto it = arguments.begin(); it != arguments.end(); ++it, i++)
        {
          if (it != arguments.begin())
            output << ",";
    
          output << R"("arg)" << i << R"(" : )";
          (*it)->writeJsonAST(output);
        }
      output << "}";
    }
    
    void
    AbstractExternalFunctionNode::writeJsonExternalFunctionArguments(ostream &output,
                                                                     const temporary_terms_t &temporary_terms,
                                                                     const deriv_node_temp_terms_t &tef_terms,
                                                                     bool isdynamic) const
    {
      for (auto it = arguments.begin(); it != arguments.end(); ++it)
        {
          if (it != arguments.begin())
            output << ",";
    
          (*it)->writeJsonOutput(output, temporary_terms, tef_terms, isdynamic);
        }
    }
    
    void
    AbstractExternalFunctionNode::writePrhs(ostream &output, ExprNodeOutputType output_type,
                                            const temporary_terms_t &temporary_terms,
                                            const temporary_terms_idxs_t &temporary_terms_idxs,
                                            const deriv_node_temp_terms_t &tef_terms) const
    {
      int i = 0;
      for (auto argument : arguments)
        {
          output << "  prhs[" << i++ << "] = mxCreateDoubleScalar("; // All external_function arguments are scalars
          argument->writeOutput(output, output_type, temporary_terms, temporary_terms_idxs, tef_terms);
          output << ");" << endl;
        }
    }
    
    bool
    AbstractExternalFunctionNode::containsExternalFunction() const
    {
      return true;
    }
    
    expr_t
    AbstractExternalFunctionNode::substituteStaticAuxiliaryVariable() const
    {
      vector<expr_t> arguments_subst;
      for (auto argument : arguments)
        arguments_subst.push_back(argument->substituteStaticAuxiliaryVariable());
      return buildSimilarExternalFunctionNode(arguments_subst, datatree);
    }
    
    expr_t
    AbstractExternalFunctionNode::replaceVarsInEquation(map<VariableNode *, NumConstNode *> &table) const
    {
      vector<expr_t> arguments_subst;
      for (auto argument : arguments)
        arguments_subst.push_back(argument->replaceVarsInEquation(table));
      return buildSimilarExternalFunctionNode(arguments_subst, datatree);
    }
    
    ExternalFunctionNode::ExternalFunctionNode(DataTree &datatree_arg,
                                               int idx_arg,
                                               int symb_id_arg,
                                               const vector<expr_t> &arguments_arg) :
      AbstractExternalFunctionNode{datatree_arg, idx_arg, symb_id_arg, arguments_arg}
    {
    }
    
    expr_t
    ExternalFunctionNode::composeDerivatives(const vector<expr_t> &dargs)
    {
      vector<expr_t> dNodes;
      for (int i = 0; i < static_cast<int>(dargs.size()); i++)
        dNodes.push_back(datatree.AddTimes(dargs.at(i),
                                           datatree.AddFirstDerivExternalFunction(symb_id, arguments, i+1)));
    
      expr_t theDeriv = datatree.Zero;
      for (auto &dNode : dNodes)
        theDeriv = datatree.AddPlus(theDeriv, dNode);
      return theDeriv;
    }
    
    void
    ExternalFunctionNode::compile(ostream &CompileCode, unsigned int &instruction_number,
                                  bool lhs_rhs, const temporary_terms_t &temporary_terms,
                                  const temporary_terms_idxs_t &temporary_terms_idxs, bool dynamic, bool steady_dynamic,
                                  const deriv_node_temp_terms_t &tef_terms) const
    {
      if (auto this2 = const_cast<ExternalFunctionNode *>(this);
          temporary_terms.find(this2) != temporary_terms.end())
        {
          if (dynamic)
            {
              FLDT_ fldt(temporary_terms_idxs.at(this2));
              fldt.write(CompileCode, instruction_number);
            }
          else
            {
              FLDST_ fldst(temporary_terms_idxs.at(this2));
              fldst.write(CompileCode, instruction_number);
            }
          return;
        }
    
      if (!lhs_rhs)
        {
          FLDTEF_ fldtef(getIndxInTefTerms(symb_id, tef_terms));
          fldtef.write(CompileCode, instruction_number);
        }
      else
        {
          FSTPTEF_ fstptef(getIndxInTefTerms(symb_id, tef_terms));
          fstptef.write(CompileCode, instruction_number);
        }
    }
    
    void
    ExternalFunctionNode::compileExternalFunctionOutput(ostream &CompileCode, unsigned int &instruction_number,
                                                        bool lhs_rhs, const temporary_terms_t &temporary_terms,
                                                        const temporary_terms_idxs_t &temporary_terms_idxs, bool dynamic, bool steady_dynamic,
                                                        deriv_node_temp_terms_t &tef_terms) const
    {
      int first_deriv_symb_id = datatree.external_functions_table.getFirstDerivSymbID(symb_id);
      assert(first_deriv_symb_id != ExternalFunctionsTable::IDSetButNoNameProvided);
    
      for (auto argument : arguments)
        argument->compileExternalFunctionOutput(CompileCode, instruction_number, lhs_rhs, temporary_terms,
                                                temporary_terms_idxs, dynamic, steady_dynamic, tef_terms);
    
      if (!alreadyWrittenAsTefTerm(symb_id, tef_terms))
        {
          tef_terms[{ symb_id, arguments }] = static_cast<int>(tef_terms.size());
          int indx = getIndxInTefTerms(symb_id, tef_terms);
          int second_deriv_symb_id = datatree.external_functions_table.getSecondDerivSymbID(symb_id);
          assert(second_deriv_symb_id != ExternalFunctionsTable::IDSetButNoNameProvided);
    
          unsigned int nb_output_arguments = 0;
          if (symb_id == first_deriv_symb_id
              && symb_id == second_deriv_symb_id)
            nb_output_arguments = 3;
          else if (symb_id == first_deriv_symb_id)
            nb_output_arguments = 2;
          else
            nb_output_arguments = 1;
          unsigned int nb_input_arguments = compileExternalFunctionArguments(CompileCode, instruction_number, lhs_rhs, temporary_terms,
                                                                             temporary_terms_idxs, dynamic, steady_dynamic, tef_terms);
    
          FCALL_ fcall(nb_output_arguments, nb_input_arguments, datatree.symbol_table.getName(symb_id), indx);
          switch (nb_output_arguments)
            {
            case 1:
              fcall.set_function_type(ExternalFunctionType::withoutDerivative);
              break;
            case 2:
              fcall.set_function_type(ExternalFunctionType::withFirstDerivative);
              break;
            case 3:
              fcall.set_function_type(ExternalFunctionType::withFirstAndSecondDerivative);
              break;
            }
          fcall.write(CompileCode, instruction_number);
          FSTPTEF_ fstptef(indx);
          fstptef.write(CompileCode, instruction_number);
        }
    }
    
    void
    ExternalFunctionNode::writeJsonAST(ostream &output) const
    {
      output << R"({"node_type" : "ExternalFunctionNode", )"
             << R"("name" : ")" << datatree.symbol_table.getName(symb_id) << R"(", "args" : [)";
      writeJsonASTExternalFunctionArguments(output);
      output << "]}";
    }
    
    void
    ExternalFunctionNode::writeJsonOutput(ostream &output,
                                          const temporary_terms_t &temporary_terms,
                                          const deriv_node_temp_terms_t &tef_terms,
                                          bool isdynamic) const
    {
      if (temporary_terms.find(const_cast<ExternalFunctionNode *>(this)) != temporary_terms.end())
        {
          output << "T" << idx;
          return;
        }
    
      try
        {
          int tef_idx = getIndxInTefTerms(symb_id, tef_terms);
          output << "TEF_" << tef_idx;
        }
      catch (UnknownFunctionNameAndArgs &)
        {
          // When writing the JSON output at parsing pass, we don’t use TEF terms
          output << datatree.symbol_table.getName(symb_id) << "(";
          writeJsonExternalFunctionArguments(output, temporary_terms, tef_terms, isdynamic);
          output << ")";
        }
    }
    
    void
    ExternalFunctionNode::writeOutput(ostream &output, ExprNodeOutputType output_type,
                                      const temporary_terms_t &temporary_terms,
                                      const temporary_terms_idxs_t &temporary_terms_idxs,
                                      const deriv_node_temp_terms_t &tef_terms) const
    {
      if (output_type == ExprNodeOutputType::matlabOutsideModel || output_type == ExprNodeOutputType::steadyStateFile
          || output_type == ExprNodeOutputType::juliaSteadyStateFile
          || output_type == ExprNodeOutputType::epilogueFile
          || output_type == ExprNodeOutputType::occbinDifferenceFile
          || isLatexOutput(output_type))
        {
          string name = isLatexOutput(output_type) ? datatree.symbol_table.getTeXName(symb_id)
            : datatree.symbol_table.getName(symb_id);
          output << name << "(";
          writeExternalFunctionArguments(output, output_type, temporary_terms, temporary_terms_idxs, tef_terms);
          output << ")";
          return;
        }
    
      if (checkIfTemporaryTermThenWrite(output, output_type, temporary_terms, temporary_terms_idxs))
        return;
    
      if (isCOutput(output_type))
        output << "*";
      output << "TEF_" << getIndxInTefTerms(symb_id, tef_terms);
    }
    
    void
    ExternalFunctionNode::writeExternalFunctionOutput(ostream &output, ExprNodeOutputType output_type,
                                                      const temporary_terms_t &temporary_terms,
                                                      const temporary_terms_idxs_t &temporary_terms_idxs,
                                                      deriv_node_temp_terms_t &tef_terms) const
    {
      int first_deriv_symb_id = datatree.external_functions_table.getFirstDerivSymbID(symb_id);
      assert(first_deriv_symb_id != ExternalFunctionsTable::IDSetButNoNameProvided);
    
      for (auto argument : arguments)
        argument->writeExternalFunctionOutput(output, output_type, temporary_terms, temporary_terms_idxs, tef_terms);
    
      if (!alreadyWrittenAsTefTerm(symb_id, tef_terms))
        {
          tef_terms[{ symb_id, arguments }] = static_cast<int>(tef_terms.size());
          int indx = getIndxInTefTerms(symb_id, tef_terms);
          int second_deriv_symb_id = datatree.external_functions_table.getSecondDerivSymbID(symb_id);
          assert(second_deriv_symb_id != ExternalFunctionsTable::IDSetButNoNameProvided);
    
          if (isCOutput(output_type))
            {
              output << "double *TEF_" << indx;
              if (symb_id == first_deriv_symb_id)
                output << ", *TEFD_" << indx;
              if (symb_id == second_deriv_symb_id)
                output << ", *TEFDD_" << indx;
              output << ";" << endl;
    
              if (symb_id == first_deriv_symb_id && symb_id == second_deriv_symb_id)
                output << "int TEFDD_" << indx << "_nrows;" << endl;
    
              int nlhs =
                symb_id == first_deriv_symb_id && symb_id == second_deriv_symb_id ? 3
                : symb_id == first_deriv_symb_id ? 2 : 1;
              output << "{" << endl
                     << "  mxArray *plhs[" << nlhs << "], *prhs[" << arguments.size() << "];" << endl;
    
              writePrhs(output, output_type, temporary_terms, temporary_terms_idxs, tef_terms);
    
              output << "  mexCallMATLAB(" << nlhs << ", plhs, " << arguments.size() << ", prhs, " << R"(")"
                     << datatree.symbol_table.getName(symb_id) << R"(");)" << endl;
    
              output << "  TEF_" << indx << " = mxGetPr(plhs[0]);" << endl;
              if (symb_id == first_deriv_symb_id)
                {
                  output << "  TEFD_" << indx << " = mxGetPr(plhs[1]);" << endl;
                  if (symb_id == second_deriv_symb_id)
                    output << "  TEFDD_" << indx << " = mxGetPr(plhs[2]);" << endl
                           << "  TEFDD_" << indx << "_nrows = (int)mxGetM(plhs[2]);" << endl;
                }
              output << "}" << endl;
            }
          else
            {
              if (symb_id == first_deriv_symb_id
                  && symb_id == second_deriv_symb_id)
                output << "[TEF_" << indx << ", TEFD_"<< indx << ", TEFDD_"<< indx << "] = ";
              else if (symb_id == first_deriv_symb_id)
                output << "[TEF_" << indx << ", TEFD_"<< indx << "] = ";
              else
                output << "TEF_" << indx << " = ";
    
              output << datatree.symbol_table.getName(symb_id) << "(";
              writeExternalFunctionArguments(output, output_type, temporary_terms, temporary_terms_idxs, tef_terms);
              output << ");" << endl;
            }
        }
    }
    
    void
    ExternalFunctionNode::writeJsonExternalFunctionOutput(vector<string> &efout,
                                                          const temporary_terms_t &temporary_terms,
                                                          deriv_node_temp_terms_t &tef_terms,
                                                          bool isdynamic) const
    {
      int first_deriv_symb_id = datatree.external_functions_table.getFirstDerivSymbID(symb_id);
      assert(first_deriv_symb_id != ExternalFunctionsTable::IDSetButNoNameProvided);
    
      for (auto argument : arguments)
        argument->writeJsonExternalFunctionOutput(efout, temporary_terms, tef_terms, isdynamic);
    
      if (!alreadyWrittenAsTefTerm(symb_id, tef_terms))
        {
          tef_terms[{ symb_id, arguments }] = static_cast<int>(tef_terms.size());
          int indx = getIndxInTefTerms(symb_id, tef_terms);
          int second_deriv_symb_id = datatree.external_functions_table.getSecondDerivSymbID(symb_id);
          assert(second_deriv_symb_id != ExternalFunctionsTable::IDSetButNoNameProvided);
    
          stringstream ef;
          ef << R"({"external_function": {)"
             << R"("external_function_term": "TEF_)" << indx << R"(")";
    
          if (symb_id == first_deriv_symb_id)
            ef << R"(, "external_function_term_d": "TEFD_)" << indx << R"(")";
    
          if (symb_id == second_deriv_symb_id)
            ef << R"(, "external_function_term_dd": "TEFDD_)" << indx << R"(")";
    
          ef << R"(, "value": ")" << datatree.symbol_table.getName(symb_id) << "(";
          writeJsonExternalFunctionArguments(ef, temporary_terms, tef_terms, isdynamic);
          ef << R"lit()"}})lit";
          efout.push_back(ef.str());
        }
    }
    
    expr_t
    ExternalFunctionNode::toStatic(DataTree &static_datatree) const
    {
      vector<expr_t> static_arguments;
      for (auto argument : arguments)
        static_arguments.push_back(argument->toStatic(static_datatree));
      return static_datatree.AddExternalFunction(symb_id, static_arguments);
    }
    
    void
    ExternalFunctionNode::computeXrefs(EquationInfo &ei) const
    {
      vector<expr_t> dynamic_arguments;
      for (auto argument : arguments)
        argument->computeXrefs(ei);
    }
    
    expr_t
    ExternalFunctionNode::clone(DataTree &datatree) const
    {
      vector<expr_t> dynamic_arguments;
      for (auto argument : arguments)
        dynamic_arguments.push_back(argument->clone(datatree));
      return datatree.AddExternalFunction(symb_id, dynamic_arguments);
    }
    
    expr_t
    ExternalFunctionNode::buildSimilarExternalFunctionNode(vector<expr_t> &alt_args, DataTree &alt_datatree) const
    {
      return alt_datatree.AddExternalFunction(symb_id, alt_args);
    }
    
    function<bool (expr_t)>
    ExternalFunctionNode::sameTefTermPredicate() const
    {
      return [this](expr_t e) {
               auto e2 = dynamic_cast<ExternalFunctionNode *>(e);
               return (e2 != nullptr && e2->symb_id == symb_id);
             };
    }
    
    FirstDerivExternalFunctionNode::FirstDerivExternalFunctionNode(DataTree &datatree_arg,
                                                                   int idx_arg,
                                                                   int top_level_symb_id_arg,
                                                                   const vector<expr_t> &arguments_arg,
                                                                   int inputIndex_arg) :
      AbstractExternalFunctionNode{datatree_arg, idx_arg, top_level_symb_id_arg, arguments_arg},
      inputIndex{inputIndex_arg}
    {
    }
    
    expr_t
    FirstDerivExternalFunctionNode::composeDerivatives(const vector<expr_t> &dargs)
    {
      vector<expr_t> dNodes;
      for (int i = 0; i < static_cast<int>(dargs.size()); i++)
        dNodes.push_back(datatree.AddTimes(dargs.at(i),
                                           datatree.AddSecondDerivExternalFunction(symb_id, arguments, inputIndex, i+1)));
      expr_t theDeriv = datatree.Zero;
      for (auto &dNode : dNodes)
        theDeriv = datatree.AddPlus(theDeriv, dNode);
      return theDeriv;
    }
    
    void
    FirstDerivExternalFunctionNode::writeJsonAST(ostream &output) const
    {
      output << R"({"node_type" : "FirstDerivExternalFunctionNode", )"
             << R"("name" : ")" << datatree.symbol_table.getName(symb_id) << R"(", "args" : [)";
      writeJsonASTExternalFunctionArguments(output);
      output << "]}";
    }
    
    void
    FirstDerivExternalFunctionNode::writeJsonOutput(ostream &output,
                                                    const temporary_terms_t &temporary_terms,
                                                    const deriv_node_temp_terms_t &tef_terms,
                                                    bool isdynamic) const
    {
      // If current node is a temporary term
      if (temporary_terms.find(const_cast<FirstDerivExternalFunctionNode *>(this)) != temporary_terms.end())
        {
          output << "T" << idx;
          return;
        }
    
      const int first_deriv_symb_id = datatree.external_functions_table.getFirstDerivSymbID(symb_id);
      assert(first_deriv_symb_id != ExternalFunctionsTable::IDSetButNoNameProvided);
    
      const int tmpIndx = inputIndex - 1;
    
      if (first_deriv_symb_id == symb_id)
        output << "TEFD_" << getIndxInTefTerms(symb_id, tef_terms)
               << "[" << tmpIndx << "]";
      else if (first_deriv_symb_id == ExternalFunctionsTable::IDNotSet)
        output << "TEFD_fdd_" << getIndxInTefTerms(symb_id, tef_terms) << "_" << inputIndex;
      else
        output << "TEFD_def_" << getIndxInTefTerms(first_deriv_symb_id, tef_terms)
               << "[" << tmpIndx << "]";
    }
    
    void
    FirstDerivExternalFunctionNode::writeOutput(ostream &output, ExprNodeOutputType output_type,
                                                const temporary_terms_t &temporary_terms,
                                                const temporary_terms_idxs_t &temporary_terms_idxs,
                                                const deriv_node_temp_terms_t &tef_terms) const
    {
      assert(output_type != ExprNodeOutputType::matlabOutsideModel
             && output_type != ExprNodeOutputType::occbinDifferenceFile);
    
      if (isLatexOutput(output_type))
        {
          output << R"(\frac{\partial )" << datatree.symbol_table.getTeXName(symb_id)
                 << R"(}{\partial )" << inputIndex << "}(";
          writeExternalFunctionArguments(output, output_type, temporary_terms, temporary_terms_idxs, tef_terms);
          output << ")";
          return;
        }
    
      if (checkIfTemporaryTermThenWrite(output, output_type, temporary_terms, temporary_terms_idxs))
        return;
    
      const int first_deriv_symb_id = datatree.external_functions_table.getFirstDerivSymbID(symb_id);
      assert(first_deriv_symb_id != ExternalFunctionsTable::IDSetButNoNameProvided);
    
      const int tmpIndx = inputIndex - 1 + ARRAY_SUBSCRIPT_OFFSET(output_type);
    
      if (first_deriv_symb_id == symb_id)
        output << "TEFD_" << getIndxInTefTerms(symb_id, tef_terms)
               << LEFT_ARRAY_SUBSCRIPT(output_type) << tmpIndx << RIGHT_ARRAY_SUBSCRIPT(output_type);
      else if (first_deriv_symb_id == ExternalFunctionsTable::IDNotSet)
        {
          if (isCOutput(output_type))
            output << "*";
          output << "TEFD_fdd_" << getIndxInTefTerms(symb_id, tef_terms) << "_" << inputIndex;
        }
      else
        output << "TEFD_def_" << getIndxInTefTerms(first_deriv_symb_id, tef_terms)
               << LEFT_ARRAY_SUBSCRIPT(output_type) << tmpIndx << RIGHT_ARRAY_SUBSCRIPT(output_type);
    }
    
    void
    FirstDerivExternalFunctionNode::compile(ostream &CompileCode, unsigned int &instruction_number,
                                            bool lhs_rhs, const temporary_terms_t &temporary_terms,
                                            const temporary_terms_idxs_t &temporary_terms_idxs, bool dynamic, bool steady_dynamic,
                                            const deriv_node_temp_terms_t &tef_terms) const
    {
      if (auto this2 = const_cast<FirstDerivExternalFunctionNode *>(this);
          temporary_terms.find(this2) != temporary_terms.end())
        {
          if (dynamic)
            {
              FLDT_ fldt(temporary_terms_idxs.at(this2));
              fldt.write(CompileCode, instruction_number);
            }
          else
            {
              FLDST_ fldst(temporary_terms_idxs.at(this2));
              fldst.write(CompileCode, instruction_number);
            }
          return;
        }
      int first_deriv_symb_id = datatree.external_functions_table.getFirstDerivSymbID(symb_id);
      assert(first_deriv_symb_id != ExternalFunctionsTable::IDSetButNoNameProvided);
    
      if (!lhs_rhs)
        {
          FLDTEFD_ fldtefd(getIndxInTefTerms(symb_id, tef_terms), inputIndex);
          fldtefd.write(CompileCode, instruction_number);
        }
      else
        {
          FSTPTEFD_ fstptefd(getIndxInTefTerms(symb_id, tef_terms), inputIndex);
          fstptefd.write(CompileCode, instruction_number);
        }
    }
    
    void
    FirstDerivExternalFunctionNode::writeExternalFunctionOutput(ostream &output, ExprNodeOutputType output_type,
                                                                const temporary_terms_t &temporary_terms,
                                                                const temporary_terms_idxs_t &temporary_terms_idxs,
                                                                deriv_node_temp_terms_t &tef_terms) const
    {
      assert(output_type != ExprNodeOutputType::matlabOutsideModel);
      int first_deriv_symb_id = datatree.external_functions_table.getFirstDerivSymbID(symb_id);
      assert(first_deriv_symb_id != ExternalFunctionsTable::IDSetButNoNameProvided);
    
      /* For a node with derivs provided by the user function, call the method
         on the non-derived node */
      if (first_deriv_symb_id == symb_id)
        {
          expr_t parent = datatree.AddExternalFunction(symb_id, arguments);
          parent->writeExternalFunctionOutput(output, output_type, temporary_terms, temporary_terms_idxs,
                                              tef_terms);
          return;
        }
    
      if (alreadyWrittenAsTefTerm(first_deriv_symb_id, tef_terms))
        return;
    
      if (isCOutput(output_type))
        if (first_deriv_symb_id == ExternalFunctionsTable::IDNotSet)
          {
            output << "double *TEFD_fdd_" <<  getIndxInTefTerms(symb_id, tef_terms) << "_" << inputIndex << ";" << endl
                   << "{" << endl
                   << "  const mwSize dims[2] = {1, " << arguments.size() << "};" << endl
                   << "  mxArray *plhs[1], *prhs[3];" << endl
                   << R"(  prhs[0] = mxCreateString(")" << datatree.symbol_table.getName(symb_id) << R"(");)" << endl
                   << "  prhs[1] = mxCreateDoubleScalar(" << inputIndex << ");"<< endl
                   << "  prhs[2] = mxCreateCellArray(2, dims);"<< endl;
    
            int i = 0;
            for (auto argument : arguments)
              {
                output << "  mxSetCell(prhs[2], " << i++ << ", "
                       << "mxCreateDoubleScalar("; // All external_function arguments are scalars
                argument->writeOutput(output, output_type, temporary_terms, temporary_terms_idxs, tef_terms);
                output << "));" << endl;
              }
    
            output << "  mexCallMATLAB(1, plhs, 3, prhs," << R"("jacob_element");)" << endl
                   << "  TEFD_fdd_" <<  getIndxInTefTerms(symb_id, tef_terms) << "_" << inputIndex
                   << " = mxGetPr(plhs[0]);" << endl
                   << "}" << endl;
          }
        else
          {
            tef_terms[{ first_deriv_symb_id, arguments }] = static_cast<int>(tef_terms.size());
            int indx = getIndxInTefTerms(first_deriv_symb_id, tef_terms);
            output << "double *TEFD_def_" << indx << ";" << endl
                   << "{" << endl
                   << "  mxArray *plhs[1], *prhs[" << arguments.size() << "];" << endl;
    
            writePrhs(output, output_type, temporary_terms, temporary_terms_idxs, tef_terms);
    
            output << "  mexCallMATLAB(1, plhs, " << arguments.size() << ", prhs," << R"(")"
                   << datatree.symbol_table.getName(first_deriv_symb_id) << R"(");)" << endl
                   << "  TEFD_def_" << indx << " = mxGetPr(plhs[0]);" << endl
                   << "}" << endl;
          }
      else
        {
          if (first_deriv_symb_id == ExternalFunctionsTable::IDNotSet)
            output << "TEFD_fdd_" << getIndxInTefTerms(symb_id, tef_terms) << "_" << inputIndex << " = jacob_element('"
                   << datatree.symbol_table.getName(symb_id) << "'," << inputIndex << ",{";
          else
            {
              tef_terms[{ first_deriv_symb_id, arguments }] = static_cast<int>(tef_terms.size());
              output << "TEFD_def_" << getIndxInTefTerms(first_deriv_symb_id, tef_terms)
                     << " = " << datatree.symbol_table.getName(first_deriv_symb_id) << "(";
            }
    
          writeExternalFunctionArguments(output, output_type, temporary_terms, temporary_terms_idxs, tef_terms);
    
          if (first_deriv_symb_id == ExternalFunctionsTable::IDNotSet)
            output << "}";
          output << ");" << endl;
        }
    }
    
    void
    FirstDerivExternalFunctionNode::writeJsonExternalFunctionOutput(vector<string> &efout,
                                                                    const temporary_terms_t &temporary_terms,
                                                                    deriv_node_temp_terms_t &tef_terms,
                                                                    bool isdynamic) const
    {
      int first_deriv_symb_id = datatree.external_functions_table.getFirstDerivSymbID(symb_id);
      assert(first_deriv_symb_id != ExternalFunctionsTable::IDSetButNoNameProvided);
    
      /* For a node with derivs provided by the user function, call the method
         on the non-derived node */
      if (first_deriv_symb_id == symb_id)
        {
          expr_t parent = datatree.AddExternalFunction(symb_id, arguments);
          parent->writeJsonExternalFunctionOutput(efout, temporary_terms, tef_terms, isdynamic);
          return;
        }
    
      if (alreadyWrittenAsTefTerm(first_deriv_symb_id, tef_terms))
        return;
    
      stringstream ef;
      if (first_deriv_symb_id == ExternalFunctionsTable::IDNotSet)
        ef << R"({"first_deriv_external_function": {)"
           << R"("external_function_term": "TEFD_fdd_)" << getIndxInTefTerms(symb_id, tef_terms) << "_" << inputIndex << R"(")"
           << R"(, "analytic_derivative": false)"
           << R"(, "wrt": )" << inputIndex
           << R"(, "value": ")" << datatree.symbol_table.getName(symb_id) << "(";
      else
        {
          tef_terms[{ first_deriv_symb_id, arguments }] = static_cast<int>(tef_terms.size());
          ef << R"({"first_deriv_external_function": {)"
             << R"("external_function_term": "TEFD_def_)" << getIndxInTefTerms(first_deriv_symb_id, tef_terms) << R"(")"
             << R"(, "analytic_derivative": true)"
             << R"(, "value": ")" << datatree.symbol_table.getName(first_deriv_symb_id) << "(";
        }
    
      writeJsonExternalFunctionArguments(ef, temporary_terms, tef_terms, isdynamic);
      ef << R"lit()"}})lit";
      efout.push_back(ef.str());
    }
    
    void
    FirstDerivExternalFunctionNode::compileExternalFunctionOutput(ostream &CompileCode, unsigned int &instruction_number,
                                                                  bool lhs_rhs, const temporary_terms_t &temporary_terms,
                                                                  const temporary_terms_idxs_t &temporary_terms_idxs, bool dynamic, bool steady_dynamic,
                                                                  deriv_node_temp_terms_t &tef_terms) const
    {
      int first_deriv_symb_id = datatree.external_functions_table.getFirstDerivSymbID(symb_id);
      assert(first_deriv_symb_id != ExternalFunctionsTable::IDSetButNoNameProvided);
    
      if (first_deriv_symb_id == symb_id || alreadyWrittenAsTefTerm(first_deriv_symb_id, tef_terms))
        return;
    
      unsigned int nb_add_input_arguments = compileExternalFunctionArguments(CompileCode, instruction_number, lhs_rhs, temporary_terms,
                                                                             temporary_terms_idxs, dynamic, steady_dynamic, tef_terms);
      if (first_deriv_symb_id == ExternalFunctionsTable::IDNotSet)
        {
          unsigned int nb_input_arguments = 0;
          unsigned int nb_output_arguments = 1;
          int indx = getIndxInTefTerms(symb_id, tef_terms);
          FCALL_ fcall(nb_output_arguments, nb_input_arguments, "jacob_element", indx);
          fcall.set_arg_func_name(datatree.symbol_table.getName(symb_id));
          fcall.set_row(inputIndex);
          fcall.set_nb_add_input_arguments(nb_add_input_arguments);
          fcall.set_function_type(ExternalFunctionType::numericalFirstDerivative);
          fcall.write(CompileCode, instruction_number);
          FSTPTEFD_ fstptefd(indx, inputIndex);
          fstptefd.write(CompileCode, instruction_number);
        }
      else
        {
          tef_terms[{ first_deriv_symb_id, arguments }] = static_cast<int>(tef_terms.size());
          int indx = getIndxInTefTerms(symb_id, tef_terms);
          int second_deriv_symb_id = datatree.external_functions_table.getSecondDerivSymbID(symb_id);
          assert(second_deriv_symb_id != ExternalFunctionsTable::IDSetButNoNameProvided);
    
          unsigned int nb_output_arguments = 1;
    
          FCALL_ fcall(nb_output_arguments, nb_add_input_arguments, datatree.symbol_table.getName(first_deriv_symb_id), indx);
          fcall.set_function_type(ExternalFunctionType::firstDerivative);
          fcall.write(CompileCode, instruction_number);
          FSTPTEFD_ fstptefd(indx, inputIndex);
          fstptefd.write(CompileCode, instruction_number);
        }
    }
    
    expr_t
    FirstDerivExternalFunctionNode::clone(DataTree &datatree) const
    {
      vector<expr_t> dynamic_arguments;
      for (auto argument : arguments)
        dynamic_arguments.push_back(argument->clone(datatree));
      return datatree.AddFirstDerivExternalFunction(symb_id, dynamic_arguments,
                                                    inputIndex);
    }
    
    expr_t
    FirstDerivExternalFunctionNode::buildSimilarExternalFunctionNode(vector<expr_t> &alt_args, DataTree &alt_datatree) const
    {
      return alt_datatree.AddFirstDerivExternalFunction(symb_id, alt_args, inputIndex);
    }
    
    expr_t
    FirstDerivExternalFunctionNode::toStatic(DataTree &static_datatree) const
    {
      vector<expr_t> static_arguments;
      for (auto argument : arguments)
        static_arguments.push_back(argument->toStatic(static_datatree));
      return static_datatree.AddFirstDerivExternalFunction(symb_id, static_arguments,
                                                           inputIndex);
    }
    
    void
    FirstDerivExternalFunctionNode::computeXrefs(EquationInfo &ei) const
    {
      vector<expr_t> dynamic_arguments;
      for (auto argument : arguments)
        argument->computeXrefs(ei);
    }
    
    function<bool (expr_t)>
    FirstDerivExternalFunctionNode::sameTefTermPredicate() const
    {
      int first_deriv_symb_id = datatree.external_functions_table.getFirstDerivSymbID(symb_id);
      if (first_deriv_symb_id == symb_id)
        return [this](expr_t e) {
          auto e2 = dynamic_cast<ExternalFunctionNode *>(e);
          return (e2 && e2->symb_id == symb_id);
        };
      else
        return [this](expr_t e) {
          auto e2 = dynamic_cast<FirstDerivExternalFunctionNode *>(e);
          return (e2 && e2->symb_id == symb_id);
        };
    }
    
    SecondDerivExternalFunctionNode::SecondDerivExternalFunctionNode(DataTree &datatree_arg,
                                                                     int idx_arg,
                                                                     int top_level_symb_id_arg,
                                                                     const vector<expr_t> &arguments_arg,
                                                                     int inputIndex1_arg,
                                                                     int inputIndex2_arg) :
      AbstractExternalFunctionNode{datatree_arg, idx_arg, top_level_symb_id_arg, arguments_arg},
      inputIndex1{inputIndex1_arg},
      inputIndex2{inputIndex2_arg}
    {
    }
    
    expr_t
    SecondDerivExternalFunctionNode::composeDerivatives(const vector<expr_t> &dargs)
    {
      cerr << "ERROR: third order derivatives of external functions are not implemented" << endl;
      exit(EXIT_FAILURE);
    }
    
    void
    SecondDerivExternalFunctionNode::writeJsonAST(ostream &output) const
    {
      output << R"({"node_type" : "SecondDerivExternalFunctionNode", )"
             << R"("name" : ")" << datatree.symbol_table.getName(symb_id) << R"(", "args" : [)";
      writeJsonASTExternalFunctionArguments(output);
      output << "]}";
    }
    
    void
    SecondDerivExternalFunctionNode::writeJsonOutput(ostream &output,
                                                     const temporary_terms_t &temporary_terms,
                                                     const deriv_node_temp_terms_t &tef_terms,
                                                     bool isdynamic) const
    {
      // If current node is a temporary term
      if (temporary_terms.find(const_cast<SecondDerivExternalFunctionNode *>(this)) != temporary_terms.end())
        {
          output << "T" << idx;
          return;
        }
    
      const int second_deriv_symb_id = datatree.external_functions_table.getSecondDerivSymbID(symb_id);
      assert(second_deriv_symb_id != ExternalFunctionsTable::IDSetButNoNameProvided);
    
      const int tmpIndex1 = inputIndex1 - 1;
      const int tmpIndex2 = inputIndex2 - 1;
    
      if (second_deriv_symb_id == symb_id)
        output << "TEFDD_" << getIndxInTefTerms(symb_id, tef_terms)
               << "[" << tmpIndex1 << "," << tmpIndex2 << "]";
      else if (second_deriv_symb_id == ExternalFunctionsTable::IDNotSet)
        output << "TEFDD_fdd_" << getIndxInTefTerms(symb_id, tef_terms) << "_" << inputIndex1 << "_" << inputIndex2;
      else
        output << "TEFDD_def_" << getIndxInTefTerms(second_deriv_symb_id, tef_terms)
               << "[" << tmpIndex1 << "," << tmpIndex2 << "]";
    }
    
    void
    SecondDerivExternalFunctionNode::writeOutput(ostream &output, ExprNodeOutputType output_type,
                                                 const temporary_terms_t &temporary_terms,
                                                 const temporary_terms_idxs_t &temporary_terms_idxs,
                                                 const deriv_node_temp_terms_t &tef_terms) const
    {
      assert(output_type != ExprNodeOutputType::matlabOutsideModel
             && output_type != ExprNodeOutputType::occbinDifferenceFile);
    
      if (isLatexOutput(output_type))
        {
          output << R"(\frac{\partial^2 )" << datatree.symbol_table.getTeXName(symb_id)
                 << R"(}{\partial )" << inputIndex1 << R"(\partial )" << inputIndex2 << "}(";
          writeExternalFunctionArguments(output, output_type, temporary_terms, temporary_terms_idxs, tef_terms);
          output << ")";
          return;
        }
    
      if (checkIfTemporaryTermThenWrite(output, output_type, temporary_terms, temporary_terms_idxs))
        return;
    
      const int second_deriv_symb_id = datatree.external_functions_table.getSecondDerivSymbID(symb_id);
      assert(second_deriv_symb_id != ExternalFunctionsTable::IDSetButNoNameProvided);
    
      const int tmpIndex1 = inputIndex1 - 1 + ARRAY_SUBSCRIPT_OFFSET(output_type);
      const int tmpIndex2 = inputIndex2 - 1 + ARRAY_SUBSCRIPT_OFFSET(output_type);
    
      int indx = getIndxInTefTerms(symb_id, tef_terms);
      if (second_deriv_symb_id == symb_id)
        if (isCOutput(output_type))
          output << "TEFDD_" << indx
                 << LEFT_ARRAY_SUBSCRIPT(output_type) << tmpIndex1 << " * TEFDD_" << indx << "_nrows + "
                 << tmpIndex2 << RIGHT_ARRAY_SUBSCRIPT(output_type);
        else
          output << "TEFDD_" << getIndxInTefTerms(symb_id, tef_terms)
                 << LEFT_ARRAY_SUBSCRIPT(output_type) << tmpIndex1 << "," << tmpIndex2 << RIGHT_ARRAY_SUBSCRIPT(output_type);
      else if (second_deriv_symb_id == ExternalFunctionsTable::IDNotSet)
        {
          if (isCOutput(output_type))
            output << "*";
          output << "TEFDD_fdd_" << getIndxInTefTerms(symb_id, tef_terms) << "_" << inputIndex1 << "_" << inputIndex2;
        }
      else
        if (isCOutput(output_type))
          output << "TEFDD_def_" << getIndxInTefTerms(second_deriv_symb_id, tef_terms)
                 << LEFT_ARRAY_SUBSCRIPT(output_type) << tmpIndex1 << " * PROBLEM_" << indx << "_nrows"
                 << tmpIndex2 << RIGHT_ARRAY_SUBSCRIPT(output_type);
        else
          output << "TEFDD_def_" << getIndxInTefTerms(second_deriv_symb_id, tef_terms)
                 << LEFT_ARRAY_SUBSCRIPT(output_type) << tmpIndex1 << "," << tmpIndex2 << RIGHT_ARRAY_SUBSCRIPT(output_type);
    }
    
    void
    SecondDerivExternalFunctionNode::writeExternalFunctionOutput(ostream &output, ExprNodeOutputType output_type,
                                                                 const temporary_terms_t &temporary_terms,
                                                                 const temporary_terms_idxs_t &temporary_terms_idxs,
                                                                 deriv_node_temp_terms_t &tef_terms) const
    {
      assert(output_type != ExprNodeOutputType::matlabOutsideModel);
      int second_deriv_symb_id = datatree.external_functions_table.getSecondDerivSymbID(symb_id);
      assert(second_deriv_symb_id != ExternalFunctionsTable::IDSetButNoNameProvided);
    
      /* For a node with derivs provided by the user function, call the method
         on the non-derived node */
      if (second_deriv_symb_id == symb_id)
        {
          expr_t parent = datatree.AddExternalFunction(symb_id, arguments);
          parent->writeExternalFunctionOutput(output, output_type, temporary_terms, temporary_terms_idxs,
                                              tef_terms);
          return;
        }
    
      if (alreadyWrittenAsTefTerm(second_deriv_symb_id, tef_terms))
        return;
    
      if (isCOutput(output_type))
        if (second_deriv_symb_id == ExternalFunctionsTable::IDNotSet)
          {
            stringstream ending;
            output << "double *TEFDD_fdd_" <<  getIndxInTefTerms(symb_id, tef_terms) << "_" << inputIndex1 << "_" << inputIndex2 << ";" << endl
                   << "{" << endl
                   << "  const mwSize dims[2]= {1, " << arguments.size() << "};" << endl
                   << "  mxArray *plhs[1], *prhs[4];" << endl
                   << R"(  prhs[0] = mxCreateString(")" << datatree.symbol_table.getName(symb_id) << R"(");)" << endl
                   << "  prhs[1] = mxCreateDoubleScalar(" << inputIndex1 << ");"<< endl
                   << "  prhs[2] = mxCreateDoubleScalar(" << inputIndex2 << ");"<< endl
                   << "  prhs[3] = mxCreateCellArray(2, dims);"<< endl;
    
            int i = 0;
            for (auto argument : arguments)
              {
                output << "  mxSetCell(prhs[3], " << i++ << ", "
                       << "  mxCreateDoubleScalar("; // All external_function arguments are scalars
                argument->writeOutput(output, output_type, temporary_terms, temporary_terms_idxs, tef_terms);
                output << "));" << endl;
              }
    
            output << "  mexCallMATLAB(1, plhs, 4, prhs, " << R"("hess_element");)" << endl
                   << "  TEFDD_fdd_" <<  getIndxInTefTerms(symb_id, tef_terms) << "_" << inputIndex1 << "_" << inputIndex2
                   << " = mxGetPr(plhs[0]);" << endl
                   << "}" << endl;
          }
        else
          {
            tef_terms[{ second_deriv_symb_id, arguments }] = static_cast<int>(tef_terms.size());
            int indx = getIndxInTefTerms(second_deriv_symb_id, tef_terms);
            output << "double *TEFDD_def_" << indx << ";" << endl
                   << "{" << endl
                   << "  mxArray *plhs[1], *prhs[" << arguments.size() << "];" << endl;
    
            writePrhs(output, output_type, temporary_terms, temporary_terms_idxs, tef_terms);
    
            output << "  mexCallMATLAB(1, plhs, " << arguments.size() << ", prhs, " << R"(")"
                   << datatree.symbol_table.getName(second_deriv_symb_id) << R"(");)" << endl
                   << "  TEFDD_def_" << indx << " = mxGetPr(plhs[0]);" << endl
                   << "}" << endl;
          }
      else
        {
          if (second_deriv_symb_id == ExternalFunctionsTable::IDNotSet)
            output << "TEFDD_fdd_" << getIndxInTefTerms(symb_id, tef_terms) << "_" << inputIndex1 << "_" << inputIndex2
                   << " = hess_element('" << datatree.symbol_table.getName(symb_id) << "',"
                   << inputIndex1 << "," << inputIndex2 << ",{";
          else
            {
              tef_terms[{ second_deriv_symb_id, arguments }] = static_cast<int>(tef_terms.size());
              output << "TEFDD_def_" << getIndxInTefTerms(second_deriv_symb_id, tef_terms)
                     << " = " << datatree.symbol_table.getName(second_deriv_symb_id) << "(";
            }
    
          writeExternalFunctionArguments(output, output_type, temporary_terms, temporary_terms_idxs, tef_terms);
    
          if (second_deriv_symb_id == ExternalFunctionsTable::IDNotSet)
            output << "}";
          output << ");" << endl;
        }
    }
    
    void
    SecondDerivExternalFunctionNode::writeJsonExternalFunctionOutput(vector<string> &efout,
                                                                     const temporary_terms_t &temporary_terms,
                                                                     deriv_node_temp_terms_t &tef_terms,
                                                                     bool isdynamic) const
    {
      int second_deriv_symb_id = datatree.external_functions_table.getSecondDerivSymbID(symb_id);
      assert(second_deriv_symb_id != ExternalFunctionsTable::IDSetButNoNameProvided);
    
      /* For a node with derivs provided by the user function, call the method
         on the non-derived node */
      if (second_deriv_symb_id == symb_id)
        {
          expr_t parent = datatree.AddExternalFunction(symb_id, arguments);
          parent->writeJsonExternalFunctionOutput(efout, temporary_terms, tef_terms, isdynamic);
          return;
        }
    
      if (alreadyWrittenAsTefTerm(second_deriv_symb_id, tef_terms))
        return;
    
      stringstream ef;
      if (second_deriv_symb_id == ExternalFunctionsTable::IDNotSet)
        ef << R"({"second_deriv_external_function": {)"
           << R"("external_function_term": "TEFDD_fdd_)" << getIndxInTefTerms(symb_id, tef_terms) << "_" << inputIndex1 << "_" << inputIndex2 << R"(")"
           << R"(, "analytic_derivative": false)"
           << R"(, "wrt1": )" << inputIndex1
           << R"(, "wrt2": )" << inputIndex2
           << R"(, "value": ")" << datatree.symbol_table.getName(symb_id) << "(";
      else
        {
          tef_terms[{ second_deriv_symb_id, arguments }] = static_cast<int>(tef_terms.size());
          ef << R"({"second_deriv_external_function": {)"
             << R"("external_function_term": "TEFDD_def_)" << getIndxInTefTerms(second_deriv_symb_id, tef_terms) << R"(")"
             << R"(, "analytic_derivative": true)"
             << R"(, "value": ")" << datatree.symbol_table.getName(second_deriv_symb_id) << "(";
        }
    
      writeJsonExternalFunctionArguments(ef, temporary_terms, tef_terms, isdynamic);
      ef << R"lit()"}})lit" << endl;
      efout.push_back(ef.str());
    }
    
    expr_t
    SecondDerivExternalFunctionNode::clone(DataTree &datatree) const
    {
      vector<expr_t> dynamic_arguments;
      for (auto argument : arguments)
        dynamic_arguments.push_back(argument->clone(datatree));
      return datatree.AddSecondDerivExternalFunction(symb_id, dynamic_arguments,
                                                     inputIndex1, inputIndex2);
    }
    
    expr_t
    SecondDerivExternalFunctionNode::buildSimilarExternalFunctionNode(vector<expr_t> &alt_args, DataTree &alt_datatree) const
    {
      return alt_datatree.AddSecondDerivExternalFunction(symb_id, alt_args, inputIndex1, inputIndex2);
    }
    
    expr_t
    SecondDerivExternalFunctionNode::toStatic(DataTree &static_datatree) const
    {
      vector<expr_t> static_arguments;
      for (auto argument : arguments)
        static_arguments.push_back(argument->toStatic(static_datatree));
      return static_datatree.AddSecondDerivExternalFunction(symb_id, static_arguments,
                                                            inputIndex1, inputIndex2);
    }
    
    void
    SecondDerivExternalFunctionNode::computeXrefs(EquationInfo &ei) const
    {
      vector<expr_t> dynamic_arguments;
      for (auto argument : arguments)
        argument->computeXrefs(ei);
    }
    
    void
    SecondDerivExternalFunctionNode::compile(ostream &CompileCode, unsigned int &instruction_number,
                                             bool lhs_rhs, const temporary_terms_t &temporary_terms,
                                             const temporary_terms_idxs_t &temporary_terms_idxs, bool dynamic, bool steady_dynamic,
                                             const deriv_node_temp_terms_t &tef_terms) const
    {
      cerr << "SecondDerivExternalFunctionNode::compile: not implemented." << endl;
      exit(EXIT_FAILURE);
    }
    
    void
    SecondDerivExternalFunctionNode::compileExternalFunctionOutput(ostream &CompileCode, unsigned int &instruction_number,
                                                                   bool lhs_rhs, const temporary_terms_t &temporary_terms,
                                                                   const temporary_terms_idxs_t &temporary_terms_idxs, bool dynamic, bool steady_dynamic,
                                                                   deriv_node_temp_terms_t &tef_terms) const
    {
      cerr << "SecondDerivExternalFunctionNode::compileExternalFunctionOutput: not implemented." << endl;
      exit(EXIT_FAILURE);
    }
    
    function<bool (expr_t)>
    SecondDerivExternalFunctionNode::sameTefTermPredicate() const
    {
      int second_deriv_symb_id = datatree.external_functions_table.getSecondDerivSymbID(symb_id);
      if (second_deriv_symb_id == symb_id)
        return [this](expr_t e) {
          auto e2 = dynamic_cast<ExternalFunctionNode *>(e);
          return (e2 && e2->symb_id == symb_id);
        };
      else
        return [this](expr_t e) {
          auto e2 = dynamic_cast<SecondDerivExternalFunctionNode *>(e);
          return (e2 && e2->symb_id == symb_id);
        };
    }
    
    SubModelNode::SubModelNode(DataTree &datatree_arg,
                               int idx_arg,
                               string model_name_arg) :
      ExprNode{datatree_arg, idx_arg},
      model_name{move(model_name_arg)}
    {
    }
    
    void
    SubModelNode::computeTemporaryTerms(const pair<int, int> &derivOrder,
                                              map<pair<int, int>, temporary_terms_t> &temp_terms_map,
                                              map<expr_t, pair<int, pair<int, int>>> &reference_count,
                                              bool is_matlab) const
    {
      cerr << "SubModelNode::computeTemporaryTerms not implemented." << endl;
      exit(EXIT_FAILURE);
    }
    
    void
    SubModelNode::computeBlockTemporaryTerms(int blk, int eq, vector<vector<temporary_terms_t>> &blocks_temporary_terms,
                                                   map<expr_t, tuple<int, int, int>> &reference_count) const
    {
      cerr << "SubModelNode::computeBlocksTemporaryTerms not implemented." << endl;
      exit(EXIT_FAILURE);
    }
    
    expr_t
    SubModelNode::toStatic(DataTree &static_datatree) const
    {
      cerr << "SubModelNode::toStatic not implemented." << endl;
      exit(EXIT_FAILURE);
    }
    
    void
    SubModelNode::prepareForDerivation()
    {
      cerr << "SubModelNode::prepareForDerivation not implemented." << endl;
      exit(EXIT_FAILURE);
    }
    
    expr_t
    SubModelNode::computeDerivative(int deriv_id)
    {
      cerr << "SubModelNode::computeDerivative not implemented." << endl;
      exit(EXIT_FAILURE);
    }
    
    expr_t
    SubModelNode::getChainRuleDerivative(int deriv_id, const map<int, BinaryOpNode *> &recursive_variables)
    {
      cerr << "SubModelNode::getChainRuleDerivative not implemented." << endl;
      exit(EXIT_FAILURE);
    }
    
    int
    SubModelNode::maxEndoLead() const
    {
      cerr << "SubModelNode::maxEndoLead not implemented." << endl;
      exit(EXIT_FAILURE);
    }
    
    int
    SubModelNode::maxExoLead() const
    {
      cerr << "SubModelNode::maxExoLead not implemented." << endl;
      exit(EXIT_FAILURE);
    }
    
    int
    SubModelNode::maxEndoLag() const
    {
      cerr << "SubModelNode::maxEndoLead not implemented." << endl;
      exit(EXIT_FAILURE);
    }
    
    int
    SubModelNode::maxExoLag() const
    {
      cerr << "SubModelNode::maxExoLead not implemented." << endl;
      exit(EXIT_FAILURE);
    }
    
    int
    SubModelNode::maxLead() const
    {
      cerr << "SubModelNode::maxLead not implemented." << endl;
      exit(EXIT_FAILURE);
    }
    
    int
    SubModelNode::maxLag() const
    {
      cerr << "SubModelNode::maxLag not implemented." << endl;
      exit(EXIT_FAILURE);
    }
    
    expr_t
    SubModelNode::undiff() const
    {
      cerr << "SubModelNode::undiff not implemented." << endl;
      exit(EXIT_FAILURE);
    }
    
    int
    SubModelNode::VarMaxLag(const set<expr_t> &lhs_lag_equiv) const
    {
      cerr << "SubModelNode::VarMaxLag not implemented." << endl;
      exit(EXIT_FAILURE);
    }
    
    expr_t
    SubModelNode::decreaseLeadsLags(int n) const
    {
      cerr << "SubModelNode::decreaseLeadsLags not implemented." << endl;
      exit(EXIT_FAILURE);
    }
    
    int
    SubModelNode::countDiffs() const
    {
      cerr << "SubModelNode::countDiffs not implemented." << endl;
      exit(EXIT_FAILURE);
    }
    
    
    expr_t
    SubModelNode::substituteEndoLeadGreaterThanTwo(subst_table_t &subst_table, vector<BinaryOpNode *> &neweqs, bool deterministic_model) const
    {
      cerr << "SubModelNode::substituteEndoLeadGreaterThanTwo not implemented." << endl;
      exit(EXIT_FAILURE);
    }
    
    expr_t
    SubModelNode::substituteEndoLagGreaterThanTwo(subst_table_t &subst_table, vector<BinaryOpNode *> &neweqs) const
    {
      cerr << "SubModelNode::substituteEndoLagGreaterThanTwo not implemented." << endl;
      exit(EXIT_FAILURE);
    }
    
    expr_t
    SubModelNode::substituteExoLead(subst_table_t &subst_table, vector<BinaryOpNode *> &neweqs, bool deterministic_model) const
    {
      cerr << "SubModelNode::substituteExoLead not implemented." << endl;
      exit(EXIT_FAILURE);
    }
    
    expr_t
    SubModelNode::substituteExoLag(subst_table_t &subst_table, vector<BinaryOpNode *> &neweqs) const
    {
      cerr << "SubModelNode::substituteExoLag not implemented." << endl;
      exit(EXIT_FAILURE);
    }
    
    bool
    SubModelNode::containsExternalFunction() const
    {
      return false;
    }
    
    double
    SubModelNode::eval(const eval_context_t &eval_context) const noexcept(false)
    {
      throw EvalException();
    }
    
    void
    SubModelNode::computeXrefs(EquationInfo &ei) const
    {
    }
    
    void
    SubModelNode::collectVARLHSVariable(set<expr_t> &result) const
    {
      cerr << "ERROR: you can only have variables or unary ops on LHS of VAR" << endl;
      exit(EXIT_FAILURE);
    }
    
    void
    SubModelNode::collectDynamicVariables(SymbolType type_arg, set<pair<int, int>> &result) const
    {
    }
    
    void
    SubModelNode::compile(ostream &CompileCode, unsigned int &instruction_number,
                                bool lhs_rhs, const temporary_terms_t &temporary_terms,
                                const temporary_terms_idxs_t &temporary_terms_idxs, bool dynamic, bool steady_dynamic,
                                const deriv_node_temp_terms_t &tef_terms) const
    {
      cerr << "SubModelNode::compile not implemented." << endl;
      exit(EXIT_FAILURE);
    }
    
    void
    SubModelNode::computeSubExprContainingVariable(int symb_id, int lag, set<expr_t> &contain_var) const
    {
    }
    
    BinaryOpNode *
    SubModelNode::normalizeEquationHelper(const set<expr_t> &contain_var, expr_t rhs) const
    {
      throw NormalizationFailed();
    }
    
    expr_t
    SubModelNode::substituteExpectation(subst_table_t &subst_table, vector<BinaryOpNode *> &neweqs, bool partial_information_model) const
    {
      return const_cast<SubModelNode *>(this);
    }
    
    expr_t
    SubModelNode::substituteAdl() const
    {
      return const_cast<SubModelNode *>(this);
    }
    
    expr_t
    SubModelNode::substituteModelLocalVariables() const
    {
      return const_cast<SubModelNode *>(this);
    }
    
    void
    SubModelNode::findDiffNodes(lag_equivalence_table_t &nodes) const
    {
    }
    
    void
    SubModelNode::findUnaryOpNodesForAuxVarCreation(lag_equivalence_table_t &nodes) const
    {
    }
    
    int
    SubModelNode::findTargetVariable(int lhs_symb_id) const
    {
      return -1;
    }
    
    expr_t
    SubModelNode::substituteDiff(const lag_equivalence_table_t &nodes, subst_table_t &subst_table,
                                       vector<BinaryOpNode *> &neweqs) const
    {
      return const_cast<SubModelNode *>(this);
    }
    
    expr_t
    SubModelNode::substituteUnaryOpNodes(const lag_equivalence_table_t &nodes, subst_table_t &subst_table, vector<BinaryOpNode *> &neweqs) const
    {
      return const_cast<SubModelNode *>(this);
    }
    
    bool
    SubModelNode::isNumConstNodeEqualTo(double value) const
    {
      return false;
    }
    
    bool
    SubModelNode::isVariableNodeEqualTo(SymbolType type_arg, int variable_id, int lag_arg) const
    {
      return false;
    }
    
    bool
    SubModelNode::isInStaticForm() const
    {
      return false;
    }
    
    bool
    SubModelNode::isParamTimesEndogExpr() const
    {
      return false;
    }
    
    expr_t
    SubModelNode::substituteStaticAuxiliaryVariable() const
    {
      return const_cast<SubModelNode *>(this);
    }
    
    expr_t
    SubModelNode::replaceVarsInEquation(map<VariableNode *, NumConstNode *> &table) const
    {
      return const_cast<SubModelNode *>(this);
    }
    
    expr_t
    SubModelNode::differentiateForwardVars(const vector<string> &subset, subst_table_t &subst_table, vector<BinaryOpNode *> &neweqs) const
    {
      cerr << "SubModelNode::differentiateForwardVars not implemented." << endl;
      exit(EXIT_FAILURE);
    }
    
    expr_t
    SubModelNode::decreaseLeadsLagsPredeterminedVariables() const
    {
      cerr << "SubModelNode::decreaseLeadsLagsPredeterminedVariables not implemented." << endl;
      exit(EXIT_FAILURE);
    }
    
    expr_t
    SubModelNode::replaceTrendVar() const
    {
      cerr << "SubModelNode::replaceTrendVar not implemented." << endl;
      exit(EXIT_FAILURE);
    }
    
    expr_t
    SubModelNode::detrend(int symb_id, bool log_trend, expr_t trend) const
    {
      cerr << "SubModelNode::detrend not implemented." << endl;
      exit(EXIT_FAILURE);
    }
    
    expr_t
    SubModelNode::removeTrendLeadLag(const map<int, expr_t> &trend_symbols_map) const
    {
      cerr << "SubModelNode::removeTrendLeadLag not implemented." << endl;
      exit(EXIT_FAILURE);
    }
    
    VarExpectationNode::VarExpectationNode(DataTree &datatree_arg,
                                           int idx_arg,
                                           string model_name_arg) :
      SubModelNode{datatree_arg, idx_arg, move(model_name_arg)}
    {
    }
    
    expr_t
    VarExpectationNode::clone(DataTree &datatree) const
    {
      return datatree.AddVarExpectation(model_name);
    }
    
    
    int
    VarExpectationNode::maxLagWithDiffsExpanded() const
    {
      /* This node will be substituted by lagged variables, so in theory we should
         return a strictly positive value. But from here this value is not easy to
         compute.
         We return 0, because currently this function is only called from
         DynamicModel::setLeadsLagsOrig(), and the maximum lag will nevertheless be
         correctly computed because the maximum lag of the VAR will be taken into
         account via the corresponding equations. */
      return 0;
    }
    
    void
    VarExpectationNode::writeOutput(ostream &output, ExprNodeOutputType output_type,
                                    const temporary_terms_t &temporary_terms,
                                    const temporary_terms_idxs_t &temporary_terms_idxs,
                                    const deriv_node_temp_terms_t &tef_terms) const
    {
      assert(output_type != ExprNodeOutputType::matlabOutsideModel);
    
      if (isLatexOutput(output_type))
        {
          output << "VAR_EXPECTATION(" << model_name << ')';
          return;
        }
    
      cerr << "VarExpectationNode::writeOutput not implemented for non-LaTeX." << endl;
      exit(EXIT_FAILURE);
    }
    
    expr_t
    VarExpectationNode::substituteVarExpectation(const map<string, expr_t> &subst_table) const
    {
      auto it = subst_table.find(model_name);
      if (it == subst_table.end())
        {
          cerr << "ERROR: unknown model '" << model_name << "' used in var_expectation expression" << endl;
          exit(EXIT_FAILURE);
        }
      return it->second;
    }
    
    expr_t
    VarExpectationNode::substitutePacExpectation(const string &name, expr_t subexpr)
    {
      return const_cast<VarExpectationNode *>(this);
    }
    
    expr_t
    VarExpectationNode::substitutePacTargetNonstationary(const string &name, expr_t subexpr)
    {
      return const_cast<VarExpectationNode *>(this);
    }
    
    bool
    VarExpectationNode::containsPacExpectation(const string &pac_model_name) const
    {
      return false;
    }
    
    bool
    VarExpectationNode::containsPacTargetNonstationary(const string &pac_model_name) const
    {
      return false;
    }
    
    void
    VarExpectationNode::writeJsonAST(ostream &output) const
    {
      output << R"({"node_type" : "VarExpectationNode", )"
             << R"("name" : ")" << model_name << R"("})";
    }
    
    void
    VarExpectationNode::writeJsonOutput(ostream &output,
                                        const temporary_terms_t &temporary_terms,
                                        const deriv_node_temp_terms_t &tef_terms,
                                        bool isdynamic) const
    {
      output << "var_expectation("
             << "model_name = " << model_name
             << ")";
    }
    
    PacExpectationNode::PacExpectationNode(DataTree &datatree_arg,
                                           int idx_arg,
                                           string model_name_arg) :
      SubModelNode{datatree_arg, idx_arg, move(model_name_arg)}
    {
    }
    
    expr_t
    PacExpectationNode::clone(DataTree &datatree) const
    {
      return datatree.AddPacExpectation(model_name);
    }
    
    void
    PacExpectationNode::writeOutput(ostream &output, ExprNodeOutputType output_type,
                                    const temporary_terms_t &temporary_terms,
                                    const temporary_terms_idxs_t &temporary_terms_idxs,
                                    const deriv_node_temp_terms_t &tef_terms) const
    {
      assert(output_type != ExprNodeOutputType::matlabOutsideModel);
      if (isLatexOutput(output_type))
        {
          output << "PAC_EXPECTATION" << LEFT_PAR(output_type) << model_name << RIGHT_PAR(output_type);
          return;
        }
    }
    
    int
    PacExpectationNode::maxLagWithDiffsExpanded() const
    {
      // Same comment as in VarExpectationNode::maxLagWithDiffsExpanded()
      return 0;
    }
    
    expr_t
    PacExpectationNode::substituteVarExpectation(const map<string, expr_t> &subst_table) const
    {
      return const_cast<PacExpectationNode *>(this);
    }
    
    bool
    PacExpectationNode::containsPacExpectation(const string &pac_model_name) const
    {
      if (pac_model_name.empty())
        return true;
      else
        return pac_model_name == model_name;
    }
    
    bool
    PacExpectationNode::containsPacTargetNonstationary(const string &pac_model_name) const
    {
      return false;
    }
    
    void
    PacExpectationNode::writeJsonAST(ostream &output) const
    {
      output << R"({"node_type" : "PacExpectationNode", )"
             << R"("name" : ")" << model_name << R"("})";
    }
    
    void
    PacExpectationNode::writeJsonOutput(ostream &output,
                                        const temporary_terms_t &temporary_terms,
                                        const deriv_node_temp_terms_t &tef_terms,
                                        bool isdynamic) const
    {
      output << "pac_expectation("
             << "model_name = " << model_name
             << ")";
    }
    
    expr_t
    PacExpectationNode::substitutePacExpectation(const string &name, expr_t subexpr)
    {
      if (model_name != name)
        return const_cast<PacExpectationNode *>(this);
      return subexpr;
    }
    
    expr_t
    PacExpectationNode::substitutePacTargetNonstationary(const string &name, expr_t subexpr)
    {
      return const_cast<PacExpectationNode *>(this);
    }
    
    PacTargetNonstationaryNode::PacTargetNonstationaryNode(DataTree &datatree_arg,
                                                           int idx_arg,
                                                           string model_name_arg) :
      SubModelNode{datatree_arg, idx_arg, move(model_name_arg)}
    {
    }
    
    expr_t
    PacTargetNonstationaryNode::clone(DataTree &datatree) const
    {
      return datatree.AddPacTargetNonstationary(model_name);
    }
    
    void
    PacTargetNonstationaryNode::writeOutput(ostream &output, ExprNodeOutputType output_type,
                                            const temporary_terms_t &temporary_terms,
                                            const temporary_terms_idxs_t &temporary_terms_idxs,
                                            const deriv_node_temp_terms_t &tef_terms) const
    {
      assert(output_type != ExprNodeOutputType::matlabOutsideModel);
      if (isLatexOutput(output_type))
        {
          output << "PAC_TARGET_NONSTATIONARY" << LEFT_PAR(output_type) << model_name << RIGHT_PAR(output_type);
          return;
        }
    }
    
    int
    PacTargetNonstationaryNode::maxLagWithDiffsExpanded() const
    {
      // This node will be replaced by the target lagged by one
      return 1;
    }
    
    expr_t
    PacTargetNonstationaryNode::substituteVarExpectation(const map<string, expr_t> &subst_table) const
    {
      return const_cast<PacTargetNonstationaryNode *>(this);
    }
    
    bool
    PacTargetNonstationaryNode::containsPacExpectation(const string &pac_model_name) const
    {
      return false;
    }
    
    bool
    PacTargetNonstationaryNode::containsPacTargetNonstationary(const string &pac_model_name) const
    {
      if (pac_model_name.empty())
        return true;
      else
        return pac_model_name == model_name;
    }
    
    void
    PacTargetNonstationaryNode::writeJsonAST(ostream &output) const
    {
      output << R"({"node_type" : "PacTargetNonstationaryNode", )"
             << R"("name" : ")" << model_name << R"("})";
    }
    
    void
    PacTargetNonstationaryNode::writeJsonOutput(ostream &output,
                                                const temporary_terms_t &temporary_terms,
                                                const deriv_node_temp_terms_t &tef_terms,
                                                bool isdynamic) const
    {
      output << "pac_target_nonstationary("
             << "model_name = " << model_name
             << ")";
    }
    
    expr_t
    PacTargetNonstationaryNode::substitutePacExpectation(const string &name, expr_t subexpr)
    {
      return const_cast<PacTargetNonstationaryNode *>(this);
    }
    
    expr_t
    PacTargetNonstationaryNode::substitutePacTargetNonstationary(const string &name, expr_t subexpr)
    {
      if (model_name != name)
        return const_cast<PacTargetNonstationaryNode *>(this);
      return subexpr;
    }
    
    void
    ExprNode::decomposeAdditiveTerms(vector<pair<expr_t, int>> &terms, int current_sign) const
    {
      terms.emplace_back(const_cast<ExprNode *>(this), current_sign);
    }
    
    void
    UnaryOpNode::decomposeAdditiveTerms(vector<pair<expr_t, int>> &terms, int current_sign) const
    {
      if (op_code == UnaryOpcode::uminus)
        arg->decomposeAdditiveTerms(terms, -current_sign);
      else
        ExprNode::decomposeAdditiveTerms(terms, current_sign);
    }
    
    void
    BinaryOpNode::decomposeAdditiveTerms(vector<pair<expr_t, int>> &terms, int current_sign) const
    {
      if (op_code == BinaryOpcode::plus || op_code == BinaryOpcode::minus)
        {
          arg1->decomposeAdditiveTerms(terms, current_sign);
          if (op_code == BinaryOpcode::plus)
            arg2->decomposeAdditiveTerms(terms, current_sign);
          else
            arg2->decomposeAdditiveTerms(terms, -current_sign);
        }
      else
        ExprNode::decomposeAdditiveTerms(terms, current_sign);
    }
    
    void
    ExprNode::decomposeMultiplicativeFactors(vector<pair<expr_t, int>> &factors, int current_exponent) const
    {
      factors.emplace_back(const_cast<ExprNode *>(this), current_exponent);
    }
    
    void
    BinaryOpNode::decomposeMultiplicativeFactors(vector<pair<expr_t, int>> &factors, int current_exponent) const
    {
      if (op_code == BinaryOpcode::times || op_code == BinaryOpcode::divide)
        {
          arg1->decomposeMultiplicativeFactors(factors, current_exponent);
          if (op_code == BinaryOpcode::times)
            arg2->decomposeMultiplicativeFactors(factors, current_exponent);
          else
            arg2->decomposeMultiplicativeFactors(factors, -current_exponent);
        }
      else
        ExprNode::decomposeMultiplicativeFactors(factors, current_exponent);
    }
    
    tuple<int, int, int, double>
    ExprNode::matchVariableTimesConstantTimesParam(bool variable_obligatory) const
    {
      int variable_id = -1, lag = 0, param_id = -1;
      double constant = 1.0;
      matchVTCTPHelper(variable_id, lag, param_id, constant, false);
      if (variable_obligatory && variable_id == -1)
        throw MatchFailureException{"No variable in this expression"};
      return {variable_id, lag, param_id, constant};
    }
    
    void
    ExprNode::matchVTCTPHelper(int &var_id, int &lag, int &param_id, double &constant, bool at_denominator) const
    {
      throw MatchFailureException{"Expression not allowed in linear combination of variables"};
    }
    
    void
    NumConstNode::matchVTCTPHelper(int &var_id, int &lag, int &param_id, double &constant, bool at_denominator) const
    {
      double myvalue = eval({});
      if (at_denominator)
        constant /= myvalue;
      else
        constant *= myvalue;
    }
    
    void
    VariableNode::matchVTCTPHelper(int &var_id, int &lag, int &param_id, double &constant, bool at_denominator) const
    {
      if (at_denominator)
        throw MatchFailureException{"A variable or parameter cannot appear at denominator"};
    
      SymbolType type = get_type();
      if (type == SymbolType::endogenous || type == SymbolType::exogenous)
        {
          if (var_id != -1)
            throw MatchFailureException{"More than one variable in this expression"};
          var_id = symb_id;
          lag = this->lag;
        }
      else if (type == SymbolType::parameter)
        {
          if (param_id != -1)
            throw MatchFailureException{"More than one parameter in this expression"};
          param_id = symb_id;
        }
      else
        throw MatchFailureException{"Symbol " + datatree.symbol_table.getName(symb_id) + " not allowed here"};
    }
    
    void
    UnaryOpNode::matchVTCTPHelper(int &var_id, int &lag, int &param_id, double &constant, bool at_denominator) const
    {
      if (op_code == UnaryOpcode::uminus)
        {
          constant = -constant;
          arg->matchVTCTPHelper(var_id, lag, param_id, constant, at_denominator);
        }
      else
        throw MatchFailureException{"Operator not allowed in this expression"};
    }
    
    void
    BinaryOpNode::matchVTCTPHelper(int &var_id, int &lag, int &param_id, double &constant, bool at_denominator) const
    {
      if (op_code == BinaryOpcode::times || op_code == BinaryOpcode::divide)
        {
          arg1->matchVTCTPHelper(var_id, lag, param_id, constant, at_denominator);
          if (op_code == BinaryOpcode::times)
            arg2->matchVTCTPHelper(var_id, lag, param_id, constant, at_denominator);
          else
            arg2->matchVTCTPHelper(var_id, lag, param_id, constant, !at_denominator);
        }
      else
        throw MatchFailureException{"Operator not allowed in this expression"};
    }
    
    vector<tuple<int, int, int, double>>
    ExprNode::matchLinearCombinationOfVariables(bool variable_obligatory_in_each_term) const
    {
      vector<pair<expr_t, int>> terms;
      decomposeAdditiveTerms(terms);
    
      vector<tuple<int, int, int, double>> result;
    
      for (auto [term, sign] : terms)
        {
          auto m = term->matchVariableTimesConstantTimesParam(variable_obligatory_in_each_term);
          get<3>(m) *= sign;
          result.push_back(m);
        }
      return result;
    }
    
    pair<int, vector<tuple<int, int, int, double>>>
    ExprNode::matchParamTimesLinearCombinationOfVariables() const
    {
      auto bopn = dynamic_cast<const BinaryOpNode *>(this);
      if (!bopn || bopn->op_code != BinaryOpcode::times)
        throw MatchFailureException{"Not a multiplicative expression"};
    
      expr_t param = bopn->arg1, lincomb = bopn->arg2;
    
      auto is_param = [](expr_t e) {
                        auto vn = dynamic_cast<VariableNode *>(e);
                        return vn && vn->get_type() == SymbolType::parameter;
                      };
    
      if (!is_param(param))
        {
          swap(param, lincomb);
          if (!is_param(param))
            throw MatchFailureException{"No parameter on either side of the multiplication"};
        }
    
      return { dynamic_cast<VariableNode *>(param)->symb_id, lincomb->matchLinearCombinationOfVariables() };
    }
    
    pair<int, int>
    ExprNode::matchParamTimesTargetMinusVariable(int symb_id) const
    {
      auto bopn = dynamic_cast<const BinaryOpNode *>(this);
      if (!bopn || bopn->op_code != BinaryOpcode::times)
        throw MatchFailureException{"Not a multiplicative expression"};
    
      expr_t param = bopn->arg1, minus = bopn->arg2;
    
      auto is_param = [](expr_t e) {
                        auto vn = dynamic_cast<VariableNode *>(e);
                        return vn && vn->get_type() == SymbolType::parameter;
                      };
    
      if (!is_param(param))
        {
          swap(param, minus);
          if (!is_param(param))
            throw MatchFailureException{"No parameter on either side of the multiplication"};
        }
    
      auto bminus = dynamic_cast<const BinaryOpNode *>(minus);
      if (!bminus || bminus->op_code != BinaryOpcode::minus)
        throw MatchFailureException{"Neither factor is a minus operator"};
    
      auto lhs_level = dynamic_cast<const VariableNode *>(bminus->arg2);
      auto target = dynamic_cast<const VariableNode *>(bminus->arg1);
    
      auto check_target = [&]()
        {
          if (target->get_type() != SymbolType::endogenous
              && target->get_type() != SymbolType::exogenous)
            return false;
          if (datatree.symbol_table.isAuxiliaryVariable(target->symb_id))
            {
              auto avi = datatree.symbol_table.getAuxVarInfo(target->symb_id);
              if (avi.get_type() == AuxVarType::pacTargetNonstationary && target->lag == -1)
                return true;
              return (avi.get_type() == AuxVarType::unaryOp
                      && avi.get_unary_op() == "log"
                      && avi.get_orig_symb_id() != -1
                      && !datatree.symbol_table.isAuxiliaryVariable(avi.get_orig_symb_id())
                      && target->lag + avi.get_orig_lead_lag() == -1);
            }
          else
            return target->lag == -1;
        };
    
      if (lhs_level && lhs_level->symb_id == symb_id && target && check_target())
        return { dynamic_cast<VariableNode *>(param)->symb_id, target->symb_id };
      else
        throw MatchFailureException{"Neither factor is of the form (target-variable) where target is endo or exo (possibly logged), and has one lag"};
    }
    
    pair<int, expr_t>
    ExprNode::matchEndogenousTimesConstant() const
    {
      throw MatchFailureException{"This expression is not of the form endogenous*constant"};
    }
    
    pair<int, expr_t>
    VariableNode::matchEndogenousTimesConstant() const
    {
      if (get_type() == SymbolType::endogenous)
        return { symb_id, datatree.One };
      else
        throw MatchFailureException{"This expression is not of the form endogenous*constant"};
    }
    
    pair<int, expr_t>
    BinaryOpNode::matchEndogenousTimesConstant() const
    {
      if (op_code == BinaryOpcode::times)
        {
          if (auto varg1 = dynamic_cast<VariableNode *>(arg1);
              varg1 && varg1->get_type() == SymbolType::endogenous && arg2->isConstant())
            return { varg1->symb_id, arg2 };
          if (auto varg2 = dynamic_cast<VariableNode *>(arg2);
              varg2 && varg2->get_type() == SymbolType::endogenous && arg1->isConstant())
            return { varg2->symb_id, arg1 };
        }
      throw MatchFailureException{"This expression is not of the form endogenous*constant"};
    }
    
    pair<vector<pair<int, expr_t>>, expr_t>
    ExprNode::matchLinearCombinationOfEndogenousWithConstant() const
    {
      vector<pair<expr_t, int>> all_terms;
      decomposeAdditiveTerms(all_terms);
    
      vector<pair<int, expr_t>> endo_terms;
      expr_t intercept = datatree.Zero;
      for (auto [term, sign] : all_terms)
        if (term->isConstant())
          {
            if (sign == -1)
              intercept = datatree.AddMinus(intercept, term);
            else
              intercept = datatree.AddPlus(intercept, term);
          }
        else
          {
            auto [endo_id, constant] = term->matchEndogenousTimesConstant();
            if (sign == -1)
              constant = datatree.AddUMinus(constant);
            endo_terms.emplace_back(endo_id, constant);
          }
      return { endo_terms, intercept };
    }