.clang-format

@@ -11,8 +11,12 @@ BreakInheritanceList: AfterColon
 Cpp11BracedListStyle: true
 DeriveLineEnding: false
 IndentPPDirectives: AfterHash
+InsertNewlineAtEOF: true
+PackConstructorInitializers: NextLine
 PPIndentWidth: 1
 PointerAlignment: Left
+# RemoveParentheses: ReturnStatement
+# RemoveSemicolon: true
 SpaceAfterTemplateKeyword: false
 SpaceBeforeParens: ControlStatements
 SpaceBeforeCpp11BracedList: true

.clang-tidy

+# TODO: add the following check families:
+# - bugprone-*
+# - cppcoreguidelines-
+
+# NB: as of clang-tidy 16, we get several false positives inside boost, notably this one:
+#  https://github.com/llvm/llvm-project/issues/40486
+
+Checks: 'performance-*,modernize-*,-modernize-use-trailing-return-type,-clang-diagnostic-unqualified-std-cast-call'

.gitlab-ci.yml

 variables:
   TERM: linux
-  MINGW32_BOOST_VERSION: 1.81.0-7
-  MINGW64_BOOST_VERSION: 1.81.0-7
+  MINGW64_BOOST_VERSION: 1.88.0-2
   WGET_OPTIONS: '--no-verbose --no-use-server-timestamps --retry-connrefused --retry-on-host-error'
   # To ensure that "false && true" fails, see https://gitlab.com/gitlab-org/gitlab-runner/-/issues/25394#note_412609647
   FF_ENABLE_BASH_EXIT_CODE_CHECK: 'true'
@@ -65,3 +64,23 @@ build_macos_arm64:
   artifacts:
     paths:
       - build/src/dynare-preprocessor
+
+test_clang_format:
+  stage: test
+  script:
+    - meson setup build-clang-format
+    - ninja -C build-clang-format clang-format-check
+  needs: []
+
+test_clang_tidy:
+  stage: test
+  script:
+    # Hack needed for meson < 1.6.0 which only looks for unversioned clang-tidy
+    - mkdir -p ~/.local/bin && ln -s /usr/bin/clang-tidy-19 ~/.local/bin/clang-tidy
+    - export PATH="$HOME/.local/bin:$PATH"
+    - meson setup build-clang-tidy
+    # Generate Flex and Bison files
+    - meson compile -C build-clang-tidy
+    - ninja -C build-clang-tidy clang-tidy
+  needs: []
+  when: manual

doc/macroprocessor/macroprocessor.tex

@@ -15,7 +15,7 @@
 \pgfdeclareimage[height=0.8cm]{logo}{dlogo}
 \institute[Dynare Team]{\pgfuseimage{logo}}
 
-\date{23 May 2023}
+\date{31 May 2024}
 
 \AtBeginSection[]
 {
@@ -156,9 +156,9 @@
     \item comparison operators: \texttt{< > <= >= == !=}
     \item logical operators: \verb+&& || !+
     \item range with unit increment: \texttt{1:4} is equivalent to
-      real array \texttt{[1, 2, 3, 4]}. (NB: \texttt{[1:4]} is equivalent to an
+      real array \texttt{[1, 2, 3, 4]} \\ (NB: \texttt{[1:4]} is equivalent to an
       array containing an array of reals, \textit{i.e.} \texttt{[[1, 2, 3, 4]]})
-    \item range with user-defined increment: \texttt{4:-1.1:-1} is equivalent to real array \texttt{[4, 2.9, 1.8, 0.7, -0.4]}.
+    \item range with user-defined increment: \\ \texttt{4:-1.1:-1} is equivalent to real array \texttt{[4, 2.9, 1.8, 0.7, -0.4]}
     \end{itemize}
   \end{block}
 
@@ -314,7 +314,7 @@ Then \texttt{distance(3, 4)} will be equivalent to \texttt{5}.
 \end{frame}
 
 \begin{frame}[fragile=singleslide]
-  \frametitle{Defining macro-variables}
+  \frametitle{Defining macro-variables (1/2)}
 
   The value of a macro-variable can be defined with the \verb+@#define+
   directive.
@@ -335,9 +335,31 @@ Then \texttt{distance(3, 4)} will be equivalent to \texttt{5}.
 @#define t = ("US" in w)    // Equals true
 \end{verbatim}
   \end{block}
-  NB: You can define macro variables on the Dynare command line by using the \texttt{-D} option
 \end{frame}
 
+\begin{frame}[fragile=singleslide]
+  \frametitle{Defining macro-variables (2/2)}
+  Macro variables can also be defined on the Dynare command line by using the
+  \texttt{-D} option, for easily switching between different flavours of a model.
+
+  \begin{block}{Example 1}
+\begin{verbatim}
+dynare myfile.mod -Dx=5
+\end{verbatim}
+The macro-variable \texttt{x} will be equal to \texttt{5} when running \texttt{myfile.mod}.
+\end{block}
+
+\begin{block}{Example 2}
+  Use single quotes around the \texttt{-D} option when there are spaces or
+  special characters in the variable definition.
+\begin{verbatim}
+dynare myfile.mod '-DA=[ i in [1,2,3] when i > 1 ]'
+\end{verbatim}
+The macro-variable \texttt{A} will be equal to \texttt{[2,3]} when running \texttt{myfile.mod}.
+\end{block}
+\end{frame}
+
+
 \begin{frame}[fragile=singleslide]
   \frametitle{Expression substitution}
   \framesubtitle{Dummy example}
@@ -611,7 +633,7 @@ end;
 \begin{frame}
   \frametitle{Macro-related command line options}
   \begin{itemize}
-  \item \texttt{savemacro}: Useful for debugging or learning purposes, saves the output of the macro processor. If your \texttt{.mod} file is called \texttt{file.mod}, the output is saved to \texttt{file-macroexp.mod}.
+  \item \texttt{savemacro}: Useful for debugging or learning purposes, saves the output of the macro processor. If your \texttt{.mod} file is called \texttt{file.mod}, the output is saved to \texttt{file\_macroexp.mod}.
   \item NB: \texttt{savemacro=filename} allows a user-defined file name
   \item \texttt{linemacro}: In the output of \texttt{savemacro}, print line numbers where the macro directives were placed.
   \item \texttt{onlymacro}: Stops processing after the macro processing step.
@@ -866,7 +888,7 @@ rhos = [ 0.8, 0.9, 1];
     \ccbysa
     \column{0.71\textwidth}
     \tiny
-    Copyright © 2008-2023 Dynare Team \\
+    Copyright © 2008-2024 Dynare Team \\
     License: \href{http://creativecommons.org/licenses/by-sa/4.0/}{Creative
       Commons Attribution-ShareAlike 4.0}
   \end{columns}

meson.build

@@ -2,7 +2,7 @@
 # It is not used when building Dynare as a whole.
 
 project('dynare-preprocessor', 'cpp',
-        version : '6-unstable',
+        version : '7-unstable',
         # NB: update C++ standard in .clang-format whenever the following is modified
         default_options : [ 'cpp_std=gnu++20', 'warning_level=2' ],
         meson_version : '>=0.64.0')

scripts/homebrew-native-arm64.ini

 # Meson native file for compiling under Homebrew / arm64
 
 [binaries]
-cpp = '/opt/homebrew/bin/g++-13'
+cpp = '/opt/homebrew/bin/g++-15'
 flex = '/opt/homebrew/opt/flex/bin/flex'
 bison = '/opt/homebrew/opt/bison/bin/bison'
 

scripts/homebrew-native-x86_64.ini

 # Meson native file for compiling under Homebrew / x86-64
 
 [binaries]
-cpp = '/usr/local/bin/g++-13'
+cpp = '/usr/local/bin/g++-15'
 flex = '/usr/local/opt/flex/bin/flex'
 bison = '/usr/local/opt/bison/bin/bison'
 

scripts/wasm.ini

+# Meson cross file for creating a WebAssembly version of the preprocessor.
+#
+# Requires emscripten to be installed.
+# Was successfully tested with emscripten 3.1.69 installed through emsdk
+# tool, as described on: https://emscripten.org/docs/getting_started/downloads.html
+# Don’t forget to source script snippet in current shell before running meson.
+#
+# Compilation creates a .wasm and .js wrapper under <builddir>/src/
+#
+# Can be run locally with node.js using:
+#  node dynare-preprocessor.js file.mod
+# NB: a version of node.js is shipped with emscripten (under the node/
+# subdirectory), but another version should also work.
+
+[binaries]
+cpp = 'em++'
+
+[host_machine]
+system = 'emscripten'
+# Could be changed to wasm64 if 4GB memory constraint is hit
+# Some background: https://v8.dev/blog/4gb-wasm-memory
+cpu_family = 'wasm32'
+cpu = 'wasm32'
+endian = 'little'
+
+[built-in options]
+# Never do a debug build, because otherwise the lack of optimisations can
+# overflow the memory capacities.
+buildtype = 'release'
+# The -fexceptions flag (for both compilation and linking) is needed for an
+# unknown reason (C++ compilers are supposed to always add exception support).
+# The -Wno-unqualified-std-cast-call flag removes many warnings about “move”
+# not being qualified with “std::” namespace.
+# The -fexperimental-library flag is needed to get std::jthread support (it was
+# supposed to no longer be necessary for LLVM 20, but for some reason we still
+# need it).
+cpp_args = [ '-fexceptions', '-Wno-unqualified-std-cast-call', '-fexperimental-library' ]
+# NODERAWFS=1 is needed for accessing the local filesystem
+cpp_link_args = [ '-s', 'NODERAWFS=1', '-fexceptions' ]
+
+[properties]
+# It’s necessary to use a different copy of Boost than the one under
+# /usr/include, because otherwise GCC headers confuse Clang
+boost_root = '/tmp/boost_1_86_0'

src/Bytecode.cc

 /*
- * Copyright © 2022-2023 Dynare Team
+ * Copyright © 2022-2024 Dynare Team
  *
  * This file is part of Dynare.
  *
@@ -17,14 +17,17 @@
  * along with Dynare.  If not, see <https://www.gnu.org/licenses/>.
  */
 
-#include <iostream>
-#include <ios>
-#include <cstdlib>
 #include <algorithm>
+#include <cstdlib>
+#include <ios>
+#include <iostream>
 
 #include "Bytecode.hh"
 
-BytecodeWriter::BytecodeWriter(const filesystem::path &filename)
+namespace Bytecode
+{
+
+Writer::Writer(const filesystem::path& filename)
 {
   open(filename, ios::out | ios::binary);
   if (!is_open())
@@ -35,17 +38,16 @@ BytecodeWriter::BytecodeWriter(const filesystem::path &filename)
 }
 
 template<>
-BytecodeWriter &
-operator<<(BytecodeWriter &code_file, const FCALL_ &instr)
+Writer&
+operator<<(Writer& code_file, const FCALL& instr)
 {
   code_file.instructions_positions.push_back(code_file.tellp());
 
-  auto write_member = [&code_file](const auto &member)
-  {
+  auto write_member = [&code_file](const auto& member) {
     code_file.write(reinterpret_cast<const char*>(&member), sizeof member);
   };
 
-  write_member(instr.op_code);
+  write_member(instr.tag);
   write_member(instr.nb_output_arguments);
   write_member(instr.nb_input_arguments);
   write_member(instr.indx);
@@ -66,23 +68,22 @@ operator<<(BytecodeWriter &code_file, const FCALL_ &instr)
 }
 
 template<>
-BytecodeWriter &
-operator<<(BytecodeWriter &code_file, const FBEGINBLOCK_ &instr)
+Writer&
+operator<<(Writer& code_file, const FBEGINBLOCK& instr)
 {
   code_file.instructions_positions.push_back(code_file.tellp());
 
-  auto write_member = [&code_file](const auto &member)
-  {
+  auto write_member = [&code_file](const auto& member) {
     code_file.write(reinterpret_cast<const char*>(&member), sizeof member);
   };
 
-  write_member(instr.op_code);
+  write_member(instr.tag);
   write_member(instr.size);
   write_member(instr.type);
   for (int i = 0; i < instr.size; i++)
     {
-      write_member(instr.variable[i]);
-      write_member(instr.equation[i]);
+      write_member(instr.variables[i]);
+      write_member(instr.equations[i]);
     }
   if (instr.type == BlockSimulationType::solveTwoBoundariesSimple
       || instr.type == BlockSimulationType::solveTwoBoundariesComplete
@@ -96,8 +97,10 @@ operator<<(BytecodeWriter &code_file, const FBEGINBLOCK_ &instr)
   write_member(instr.det_exo_size);
   write_member(instr.exo_size);
 
-  for_each_n(instr.det_exogenous.begin(), instr.det_exo_size, write_member);
-  for_each_n(instr.exogenous.begin(), instr.exo_size, write_member);
+  ranges::for_each_n(instr.det_exogenous.begin(), instr.det_exo_size, write_member);
+  ranges::for_each_n(instr.exogenous.begin(), instr.exo_size, write_member);
 
   return code_file;
 }
+
+}

src/CommonEnums.hh

 /*
- * Copyright © 2007-2022 Dynare Team
+ * Copyright © 2007-2024 Dynare Team
  *
  * This file is part of Dynare.
  *
@@ -17,24 +17,30 @@
  * along with Dynare.  If not, see <https://www.gnu.org/licenses/>.
  */
 
-#ifndef _COMMON_ENUMS_HH
-#define _COMMON_ENUMS_HH
+#ifndef COMMON_ENUMS_HH
+#define COMMON_ENUMS_HH
 
 //! Enumeration of possible symbol types
-/*! Warning: do not to change existing values for 0 to 4: the values matter for homotopy_setup command */
+/*! Warning: do not to change existing values for 0 to 4: the values matter for homotopy_setup
+ * command */
 enum class SymbolType
 {
-   endogenous = 0, //!< Endogenous
-   exogenous = 1, //!< Exogenous
-   exogenousDet = 2, //!< Exogenous deterministic
-   parameter = 4, //!< Parameter
-   modelLocalVariable = 10, //!< Local variable whose scope is model (pound expression)
-   modFileLocalVariable = 11, //!< Local variable whose scope is mod file (model excluded)
-   externalFunction = 12, //!< External (user-defined) function
-   trend = 13, //!< Trend variable
-   statementDeclaredVariable = 14, //!< Local variable assigned within a Statement (see subsample statement for example)
+  endogenous = 0,              // Endogenous (non-heterogeneous)
+  exogenous = 1,               // Exogenous (non-heterogeneous)
+  exogenousDet = 2,            // Exogenous deterministic (non-heterogeneous)
+  parameter = 4,               // Parameter (non-heterogeneous)
+  heterogeneousEndogenous = 5, // Endogenous that is heterogeneous across some dimension
+  heterogeneousExogenous = 6,  // Exogenous that is heterogeneous across some dimension
+  heterogeneousParameter = 7,  // Parameter that is heterogeneous across some dimension
+  modelLocalVariable = 10,     // Local variable whose scope is model (pound expression)
+  modFileLocalVariable = 11,   // Local variable whose scope is mod file (model excluded)
+  externalFunction = 12,       // External (user-defined) function
+  trend = 13,                  // Trend variable
+  statementDeclaredVariable
+  = 14, //!< Local variable assigned within a Statement (see subsample statement for example)
   logTrend = 15, //!< Log-trend variable
-   unusedEndogenous = 16, //!< Type to mark unused endogenous variables when `nostrict` option is passed
+  unusedEndogenous
+  = 16, //!< Type to mark unused endogenous variables when `nostrict` option is passed
 
   // Value 17 is unused for the time being (but could be reused)
 
@@ -42,6 +48,13 @@ enum class SymbolType
   excludedVariable = 19 //!< Variable excluded via model_remove/var_remove/include_eqs/exclude_eqs
 };
 
+constexpr bool
+isHeterogeneous(SymbolType type)
+{
+  return type == SymbolType::heterogeneousEndogenous || type == SymbolType::heterogeneousExogenous
+         || type == SymbolType::heterogeneousParameter;
+}
+
 enum class UnaryOpcode
 {
   uminus,
@@ -66,12 +79,14 @@ enum class UnaryOpcode
   sign,
   steadyState,
   steadyStateParamDeriv,    // for the derivative of the STEADY_STATE operator w.r.t. to a parameter
-   steadyStateParam2ndDeriv, // for the 2nd derivative of the STEADY_STATE operator w.r.t. to a parameter
+  steadyStateParam2ndDeriv, // for the 2nd derivative of the STEADY_STATE operator w.r.t. to a
+                            // parameter
   expectation,
   erf,
   erfc,
   diff,
-   adl
+  adl,
+  sum
 };
 
 enum class BinaryOpcode
@@ -119,8 +134,10 @@ enum class PriorDistributions
 
 enum class EquationType
 {
-   evaluate, //!< Simple evaluation, normalized variable on left-hand side (written as such by the user)
-   evaluateRenormalized, //!< Simple evaluation, normalized variable on left-hand side (normalization computed by the preprocessor)
+  evaluate, //!< Simple evaluation, normalized variable on left-hand side (written as such by the
+            //!< user)
+  evaluateRenormalized, //!< Simple evaluation, normalized variable on left-hand side (normalization
+                        //!< computed by the preprocessor)
   solve                 //!< No simple evaluation of the equation, it has to be solved
 };
 
@@ -133,7 +150,8 @@ enum class BlockSimulationType
   solveTwoBoundariesSimple,  //!< Block of one equation, Newton solver needed, forward and backward
   solveForwardComplete,      //!< Block of several equations, Newton solver needed, forward
   solveBackwardComplete,     //!< Block of several equations, Newton solver needed, backward
-   solveTwoBoundariesComplete //!< Block of several equations, Newton solver needed, forward and backwar
+  solveTwoBoundariesComplete //!< Block of several equations, Newton solver needed, forward and
+                             //!< backwar
 };
 
 enum class PacTargetKind
@@ -144,4 +162,4 @@ enum class PacTargetKind
   dd
 };
 
-#endif // _COMMON_ENUMS_HH
+#endif

src/ConfigFile.hh → src/Configuration.hh

@@ -17,57 +17,49 @@
  * along with Dynare.  If not, see <https://www.gnu.org/licenses/>.
  */
 
-#ifndef _CONFIG_FILE_HH
-#define _CONFIG_FILE_HH
+#ifndef CONFIGURATION_HH
+#define CONFIGURATION_HH
 
+#include <filesystem>
 #include <map>
 #include <vector>
-#include <filesystem>
 
 #include "WarningConsolidation.hh"
 
 using namespace std;
 
-using member_nodes_t = map<string, double>;
-
-class Hook
+/* The abstract representation of the configuration.
+   Merges information from the command-line and from the configuration file. */
+class Configuration
 {
 public:
-  explicit Hook(string global_init_file_arg);
+  Configuration(bool parallel_arg, bool parallel_test_arg, bool parallel_follower_open_mode_arg,
+                bool parallel_use_psexec_arg, string cluster_name);
+
 private:
-  map<string, string> hooks;
-public:
-  map<string, string>
-  get_hooks() const
-  {
-    return hooks;
-  };
-};
+  using member_nodes_t = map<string, double>;
 
   class Path
   {
   public:
     explicit Path(vector<string> includepath_arg);
-private:
-  map<string, vector<string>> paths;
-public:
-  map<string, vector<string>>
+    [[nodiscard]] map<string, vector<string>>
     get_paths() const
     {
       return paths;
-  };
+    }
+
+  private:
+    map<string, vector<string>> paths;
   };
 
-class FollowerNode
+  struct FollowerNode
   {
-  friend class ConfigFile;
-public:
-  FollowerNode(string computerName_arg, string port_arg, int minCpuNbr_arg, int maxCpuNbr_arg, string userName_arg,
-               string password_arg, string remoteDrive_arg, string remoteDirectory_arg,
-               string programPath_arg, string programConfig_arg, string matlabOctavePath_arg, bool singleCompThread_arg,
+    FollowerNode(string computerName_arg, string port_arg, int minCpuNbr_arg, int maxCpuNbr_arg,
+                 string userName_arg, string password_arg, string remoteDrive_arg,
+                 string remoteDirectory_arg, string programPath_arg, string programConfig_arg,
+                 string matlabOctavePath_arg, bool singleCompThread_arg,
                  int numberOfThreadsPerJob_arg, string operatingSystem_arg);
-
-protected:
     const string computerName, port;
     int minCpuNbr, maxCpuNbr;
     const string userName, password;
@@ -78,55 +70,51 @@ protected:
     const string operatingSystem;
   };
 
-class Cluster
+  struct Cluster
   {
-  friend class ConfigFile;
-public:
     explicit Cluster(member_nodes_t member_nodes_arg);
-
-protected:
     member_nodes_t member_nodes;
   };
 
-//! The abstract representation of a "config" file
-class ConfigFile
-{
-public:
-  ConfigFile(bool parallel_arg, bool parallel_test_arg, bool parallel_follower_open_mode_arg,
-             bool parallel_use_psexec_arg, string cluster_name);
-
-private:
   const bool parallel, parallel_test, parallel_follower_open_mode, parallel_use_psexec;
   const string cluster_name;
   string firstClusterName;
   //! Hooks
-  vector<Hook> hooks;
+  string global_init_file;
   //! Paths
   vector<Path> paths;
   //! Cluster Table
   map<string, Cluster> clusters;
   //! Node Map
   map<string, FollowerNode> follower_nodes;
-  //! Add Hooks
-  void addHooksConfFileElement(string global_init_file);
   //! Add Paths
   void addPathsConfFileElement(vector<string> includepath);
   //! Add a FollowerNode or a Cluster object
-  void addParallelConfFileElement(bool inNode, bool inCluster, const member_nodes_t &member_nodes, const string &name,
-                                  const string &computerName, const string &port, int minCpuNbr, int maxCpuNbr,
-                                  const string &userName, const string &password, const string &remoteDrive,
-                                  const string &remoteDirectory, const string &programPath, const string &programConfig,
-                                  const string &matlabOctavePath, bool singleCompThread, int numberOfThreadsPerJob,
-                                  const string &operatingSystem);
+  void addParallelConfFileElement(bool inNode, bool inCluster, const member_nodes_t& member_nodes,
+                                  const string& name, const string& computerName,
+                                  const string& port, int minCpuNbr, int maxCpuNbr,
+                                  const string& userName, const string& password,
+                                  const string& remoteDrive, const string& remoteDirectory,
+                                  const string& programPath, const string& programConfig,
+                                  const string& matlabOctavePath, bool singleCompThread,
+                                  int numberOfThreadsPerJob, const string& operatingSystem);
+  /* Given a filename (e.g. dynare.ini), looks for it in the configuration directory:
+     – if under Linux or macOS, look into the “dynare” subdirectory of the XDG
+       configuration directories (following the default values and the precedence order specified in
+       the XDG specification)
+     – if under Windows, look into %APPDATA%\dynare\
+     The returned path will be empty if the file is not found. */
+  [[nodiscard]] static filesystem::path findConfigFile(const string& filename);
+
 public:
   //! Parse config file
-  void getConfigFileInfo(const filesystem::path &parallel_config_file);
+  void getConfigFileInfo(const filesystem::path& conffile_option, WarningConsolidation& warnings);
   //! Check Pass
   void checkPass(WarningConsolidation& warnings) const;
   //! Check Pass
   void transformPass();
   //! Get Path Info
-  vector<filesystem::path> getIncludePaths() const;
+  [[nodiscard]] vector<filesystem::path> getIncludePaths() const;
   //! Write any hooks
   void writeHooks(ostream& output) const;
   //! Create options_.parallel structure, write options
@@ -135,4 +123,4 @@ public:
   void writeEndParallel(ostream& output) const;
 };
 
-#endif // ! CONFIG_FILE_HH
+#endif

src/DataTree.cc

 /*
- * Copyright © 2003-2023 Dynare Team
+ * Copyright © 2003-2025 Dynare Team
  *
  * This file is part of Dynare.
  *
@@ -17,13 +17,14 @@
  * along with Dynare.  If not, see <https://www.gnu.org/licenses/>.
  */
 
-#include <cstdlib>
-#include <cassert>
-#include <iostream>
 #include <algorithm>
-#include <iterator>
+#include <cassert>
+#include <cstdlib>
 #include <filesystem>
 #include <fstream>
+#include <iostream>
+#include <iterator>
+#include <ranges>
 
 #include "DataTree.hh"
 
@@ -46,13 +47,13 @@ DataTree::initConstants()
   Pi = AddNonNegativeConstant("3.141592653589793");
 }
 
-DataTree::DataTree(SymbolTable &symbol_table_arg,
-                   NumericalConstants &num_constants_arg,
+DataTree::DataTree(SymbolTable& symbol_table_arg, NumericalConstants& num_constants_arg,
                    ExternalFunctionsTable& external_functions_table_arg,
-                   bool is_dynamic_arg) :
+                   HeterogeneityTable& heterogeneity_table_arg, bool is_dynamic_arg) :
     symbol_table {symbol_table_arg},
     num_constants {num_constants_arg},
     external_functions_table {external_functions_table_arg},
+    heterogeneity_table {heterogeneity_table_arg},
     is_dynamic {is_dynamic_arg}
 {
   initConstants();
@@ -62,19 +63,21 @@ DataTree::DataTree(const DataTree &d) :
     symbol_table {d.symbol_table},
     num_constants {d.num_constants},
     external_functions_table {d.external_functions_table},
+    heterogeneity_table {d.heterogeneity_table},
     is_dynamic {d.is_dynamic},
     local_variables_vector {d.local_variables_vector}
 {
   // Constants must be initialized first because they are used in some Add* methods
   initConstants();
 
+  // See commment in DataTree::operator=() for the rationale
+  for (int symb_id : d.local_variables_vector)
+    local_variables_table[symb_id] = d.local_variables_table.at(symb_id)->clone(*this);
+
   for (const auto& it : d.node_list)
     it->clone(*this);
 
   assert(node_list.size() == d.node_list.size());
-
-  for (const auto &[symb_id, value] : d.local_variables_table)
-    local_variables_table[symb_id] = value->clone(*this);
 }
 
 DataTree&
@@ -83,6 +86,7 @@ DataTree::operator=(const DataTree &d)
   assert(&symbol_table == &d.symbol_table);
   assert(&num_constants == &d.num_constants);
   assert(&external_functions_table == &d.external_functions_table);
+  assert(&heterogeneity_table == &d.heterogeneity_table);
   assert(is_dynamic == d.is_dynamic);
 
   num_const_node_map.clear();
@@ -125,8 +129,7 @@ DataTree::AddNonNegativeConstant(const string &value)
 {
   int id = num_constants.AddNonNegativeConstant(value);
 
-  if (auto it = num_const_node_map.find(id);
-      it != num_const_node_map.end())
+  if (auto it = num_const_node_map.find(id); it != num_const_node_map.end())
     return it->second;
 
   auto sp = make_unique<NumConstNode>(*this, node_list.size(), id);
@@ -145,8 +148,7 @@ DataTree::AddVariable(int symb_id, int lag)
       exit(EXIT_FAILURE);
     }
 
-  if (auto it = variable_node_map.find({ symb_id, lag });
-      it != variable_node_map.end())
+  if (auto it = variable_node_map.find({symb_id, lag}); it != variable_node_map.end())
     return it->second;
 
   auto sp = make_unique<VariableNode>(*this, node_list.size(), symb_id, lag);
@@ -162,7 +164,8 @@ DataTree::getVariable(int symb_id, int lag) const
   auto it = variable_node_map.find({symb_id, lag});
   if (it == variable_node_map.end())
     {
-      cerr << "DataTree::getVariable: unknown variable node for symb_id=" << symb_id << " and lag=" << lag << endl;
+      cerr << "DataTree::getVariable: unknown variable node for symb_id=" << symb_id
+           << " and lag=" << lag << endl;
       exit(EXIT_FAILURE);
     }
   return it->second;
@@ -208,7 +211,7 @@ DataTree::AddPlus(expr_t iArg1, expr_t iArg2)
 
   // To treat commutativity of "+"
   // Nodes iArg1 and iArg2 are sorted by index
-  if (iArg1->idx > iArg2->idx && !no_commutativity)
+  if (iArg1->idx > iArg2->idx && !no_commutativity) // NOLINT(clang-analyzer-core.NullDereference)
     swap(iArg1, iArg2);
   return AddBinaryOp(iArg1, BinaryOpcode::plus, iArg2);
 }
@@ -250,8 +253,7 @@ DataTree::AddUMinus(expr_t iArg1)
     return Zero;
 
   // Simplify -(-x) in x
-  if (auto uarg = dynamic_cast<UnaryOpNode *>(iArg1);
-      uarg && uarg->op_code == UnaryOpcode::uminus)
+  if (auto uarg = dynamic_cast<UnaryOpNode*>(iArg1); uarg && uarg->op_code == UnaryOpcode::uminus)
     return uarg->arg;
 
   return AddUnaryOp(UnaryOpcode::uminus, iArg1);
@@ -287,7 +289,7 @@ DataTree::AddTimes(expr_t iArg1, expr_t iArg2)
 
   // To treat commutativity of "*"
   // Nodes iArg1 and iArg2 are sorted by index
-  if (iArg1->idx > iArg2->idx && !no_commutativity)
+  if (iArg1->idx > iArg2->idx && !no_commutativity) // NOLINT(clang-analyzer-core.NullDereference)
     swap(iArg1, iArg2);
   return AddBinaryOp(iArg1, BinaryOpcode::times, iArg2);
 }
@@ -668,7 +670,8 @@ DataTree::AddSteadyStateParamDeriv(expr_t iArg1, int param_symb_id)
 expr_t
 DataTree::AddSteadyStateParam2ndDeriv(expr_t iArg1, int param1_symb_id, int param2_symb_id)
 {
-  return AddUnaryOp(UnaryOpcode::steadyStateParam2ndDeriv, iArg1, 0, param1_symb_id, param2_symb_id);
+  return AddUnaryOp(UnaryOpcode::steadyStateParam2ndDeriv, iArg1, 0, param1_symb_id,
+                    param2_symb_id);
 }
 
 expr_t
@@ -680,8 +683,7 @@ DataTree::AddExpectation(int iArg1, expr_t iArg2)
 expr_t
 DataTree::AddVarExpectation(const string& model_name)
 {
-  if (auto it = var_expectation_node_map.find(model_name);
-      it != var_expectation_node_map.end())
+  if (auto it = var_expectation_node_map.find(model_name); it != var_expectation_node_map.end())
     return it->second;
 
   auto sp = make_unique<VarExpectationNode>(*this, node_list.size(), model_name);
@@ -694,8 +696,7 @@ DataTree::AddVarExpectation(const string &model_name)
 expr_t
 DataTree::AddPacExpectation(const string& model_name)
 {
-  if (auto it = pac_expectation_node_map.find(model_name);
-      it != pac_expectation_node_map.end())
+  if (auto it = pac_expectation_node_map.find(model_name); it != pac_expectation_node_map.end())
     return it->second;
 
   auto sp = make_unique<PacExpectationNode>(*this, node_list.size(), model_name);
@@ -757,43 +758,56 @@ DataTree::AddExternalFunction(int symb_id, const vector<expr_t> &arguments)
 }
 
 expr_t
-DataTree::AddFirstDerivExternalFunction(int top_level_symb_id, const vector<expr_t> &arguments, int input_index)
+DataTree::AddFirstDerivExternalFunction(int top_level_symb_id, const vector<expr_t>& arguments,
+                                        int input_index)
 {
   assert(symbol_table.getType(top_level_symb_id) == SymbolType::externalFunction);
 
-  if (auto it = first_deriv_external_function_node_map.find({ arguments, input_index, top_level_symb_id });
+  if (auto it
+      = first_deriv_external_function_node_map.find({arguments, input_index, top_level_symb_id});
       it != first_deriv_external_function_node_map.end())
     return it->second;
 
-  auto sp = make_unique<FirstDerivExternalFunctionNode>(*this, node_list.size(), top_level_symb_id, arguments, input_index);
+  auto sp = make_unique<FirstDerivExternalFunctionNode>(*this, node_list.size(), top_level_symb_id,
+                                                        arguments, input_index);
   auto p = sp.get();
   node_list.push_back(move(sp));
-  first_deriv_external_function_node_map.try_emplace({ arguments, input_index, top_level_symb_id }, p);
+  first_deriv_external_function_node_map.try_emplace({arguments, input_index, top_level_symb_id},
+                                                     p);
   return p;
 }
 
 expr_t
-DataTree::AddSecondDerivExternalFunction(int top_level_symb_id, const vector<expr_t> &arguments, int input_index1, int input_index2)
+DataTree::AddSecondDerivExternalFunction(int top_level_symb_id, const vector<expr_t>& arguments,
+                                         int input_index1, int input_index2)
 {
   assert(symbol_table.getType(top_level_symb_id) == SymbolType::externalFunction);
 
-  if (auto it = second_deriv_external_function_node_map.find({ arguments, input_index1, input_index2,
-                                                               top_level_symb_id });
+  if (auto it = second_deriv_external_function_node_map.find(
+          {arguments, input_index1, input_index2, top_level_symb_id});
       it != second_deriv_external_function_node_map.end())
     return it->second;
 
-  auto sp = make_unique<SecondDerivExternalFunctionNode>(*this, node_list.size(), top_level_symb_id, arguments, input_index1, input_index2);
+  auto sp = make_unique<SecondDerivExternalFunctionNode>(*this, node_list.size(), top_level_symb_id,
+                                                         arguments, input_index1, input_index2);
   auto p = sp.get();
   node_list.push_back(move(sp));
-  second_deriv_external_function_node_map.try_emplace({ arguments, input_index1, input_index2, top_level_symb_id }, p);
+  second_deriv_external_function_node_map.try_emplace(
+      {arguments, input_index1, input_index2, top_level_symb_id}, p);
   return p;
 }
 
+expr_t
+DataTree::AddSum(expr_t arg)
+{
+  return AddUnaryOp(UnaryOpcode::sum, arg);
+}
+
 bool
 DataTree::isSymbolUsed(int symb_id) const
 {
-  for (const auto &[symb_lag, expr] : variable_node_map)
-    if (symb_lag.first == symb_id)
+  if (ranges::any_of(views::keys(variable_node_map),
+                     [=](const auto& symb_lag) { return symb_lag.first == symb_id; }))
     return true;
 
   if (local_variables_table.contains(symb_id))
@@ -840,18 +854,18 @@ DataTree::addAllParamDerivId([[maybe_unused]] set<int> &deriv_id_set)
 bool
 DataTree::isUnaryOpUsed(UnaryOpcode opcode) const
 {
-  return any_of(unary_op_node_map.begin(), unary_op_node_map.end(),
-                [=](const auto &it) { return get<1>(it.first) == opcode; });
+  return ranges::any_of(views::keys(unary_op_node_map),
+                        [=](const auto& key) { return get<1>(key) == opcode; });
 }
 
 bool
 DataTree::isUnaryOpUsedOnType(SymbolType type, UnaryOpcode opcode) const
 {
   set<int> var;
-  for (const auto &it : unary_op_node_map)
-    if (get<1>(it.first) == opcode)
+  for (const auto& [key, value] : unary_op_node_map)
+    if (get<1>(key) == opcode)
       {
-        it.second->collectVariables(type, var);
+        value->collectVariables(type, var);
         if (!var.empty())
           return true;
       }
@@ -861,18 +875,18 @@ DataTree::isUnaryOpUsedOnType(SymbolType type, UnaryOpcode opcode) const
 bool
 DataTree::isBinaryOpUsed(BinaryOpcode opcode) const
 {
-  return any_of(binary_op_node_map.begin(), binary_op_node_map.end(),
-                [=](const auto &it) { return get<2>(it.first) == opcode; });
+  return ranges::any_of(views::keys(binary_op_node_map),
+                        [=](const auto& key) { return get<2>(key) == opcode; });
 }
 
 bool
 DataTree::isBinaryOpUsedOnType(SymbolType type, BinaryOpcode opcode) const
 {
   set<int> var;
-  for (const auto &it : binary_op_node_map)
-    if (get<2>(it.first) == opcode)
+  for (const auto& [key, value] : binary_op_node_map)
+    if (get<2>(key) == opcode)
       {
-        it.second->collectVariables(type, var);
+        value->collectVariables(type, var);
         if (!var.empty())
           return true;
       }
@@ -897,7 +911,9 @@ DataTree::writeCHelpersDefinition(ostream &output) const
            << "inline double" << endl
            << "getPowerDeriv(double x, double p, int k)" << endl
            << "{" << endl
-           << "  if (fabs(x) < " << power_deriv_near_zero << " && p > 0 && k > p && fabs(p-nearbyint(p)) < " << power_deriv_near_zero << ')' << endl
+           << "  if (fabs(x) < " << power_deriv_near_zero
+           << " && p >= 0 && k > p && fabs(p-nearbyint(p)) < " << power_deriv_near_zero << ')'
+           << endl
            << "    return 0.0;" << endl
            << "  else" << endl
            << "    {" << endl
@@ -932,8 +948,7 @@ DataTree::strsplit(string_view str, char delim)
   while (true)
     {
       size_t idx {str.find(delim)};
-      if (auto sub {str.substr(0, idx)};
-          !sub.empty())
+      if (auto sub {str.substr(0, idx)}; !sub.empty())
         result.emplace_back(sub);
       if (idx == string_view::npos)
         break;
@@ -943,10 +958,10 @@ DataTree::strsplit(string_view str, char delim)
 }
 
 filesystem::path
-DataTree::packageDir(string_view package)
+DataTree::packageDir(const string_view& package)
 {
   filesystem::path d;
-  for (const auto &it : strsplit(move(package), '.'))
+  for (const auto& it : strsplit(package, '.'))
     d /= "+" + it;
   return d;
 }
@@ -956,7 +971,7 @@ DataTree::writeToFileIfModified(stringstream &new_contents, const filesystem::pa
 {
   ifstream old_file {filename, ios::in | ios::binary};
   if (old_file.is_open()
-      && equal(istreambuf_iterator<char>{old_file}, istreambuf_iterator<char>{},
+      && ranges::equal(istreambuf_iterator<char> {old_file}, istreambuf_iterator<char> {},
                        istreambuf_iterator<char> {new_contents}, istreambuf_iterator<char> {}))
     return;
   old_file.close();
@@ -969,7 +984,7 @@ DataTree::writeToFileIfModified(stringstream &new_contents, const filesystem::pa
       cerr << "ERROR: Can't open file " << filename.string() << " for writing" << endl;
       exit(EXIT_FAILURE);
     }
-  copy(istreambuf_iterator<char>{new_contents}, istreambuf_iterator<char>{},
+  ranges::copy(istreambuf_iterator<char> {new_contents}, istreambuf_iterator<char> {},
                ostreambuf_iterator<char> {new_file});
   new_file.close();
 }