diff --git a/matlab/backward/dynamic_static_model_for_simulation.m b/matlab/backward/dynamic_static_model_for_simulation.m
new file mode 100644
index 0000000000000000000000000000000000000000..8ce6083330475e8892dd12e49f60006556e5987f
--- /dev/null
+++ b/matlab/backward/dynamic_static_model_for_simulation.m
@@ -0,0 +1,29 @@
+function [r, J] = dynamic_static_model_for_simulation(z, dynamicmodel, x, params, steady_state, it_)
+
+% Copyright © 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 <http://www.gnu.org/licenses/>.
+
+% NOTE: It is assumed that all variables appear at time t in the model.
+
+if nargout>1
+ % Compute residuals and jacobian of the full dynamic model.
+ [r, J] = feval(dynamicmodel, z, x, params, steady_state, it_);
+ J = J(:,1:rows(J)); % Remove derivatives with respect to shocks.
+else
+ % Compute residuals.
+ r = feval(dynamicmodel, z, x, params, steady_state, it_);
+end
\ No newline at end of file
diff --git a/matlab/perfect-foresight-models/perfect_foresight_solver.m b/matlab/perfect-foresight-models/perfect_foresight_solver.m
index e675b7fecd17364c2affe08bec5d1723ad838bd3..37bf898f98e918fb4657914c6598b38715030b53 100644
--- a/matlab/perfect-foresight-models/perfect_foresight_solver.m
+++ b/matlab/perfect-foresight-models/perfect_foresight_solver.m
@@ -70,14 +70,15 @@ if ~oo_.deterministic_simulation.status && ~options_.no_homotopy
fprintf('Switching to a homotopy method...\n')
end
- if ~M_.maximum_lag
+ if ~M_.maximum_lag && M_.maximum_lead>0
disp('Homotopy not implemented for purely forward models!')
disp('Failed to solve the model!')
disp('Return with empty oo_.endo_simul.')
oo_.endo_simul = [];
return
end
- if ~M_.maximum_lead
+
+ if ~M_.maximum_lead && M_.maximum_lag>0
disp('Homotopy not implemented for purely backward models!')
disp('Failed to solve the model!')
disp('Return with empty oo_.endo_simul.')
@@ -85,6 +86,14 @@ if ~oo_.deterministic_simulation.status && ~options_.no_homotopy
return
end
+ if ~M_.maximum_lead && ~M_.maximum_lag
+ disp('Homotopy not implemented for purely static models!')
+ disp('Failed to solve the model!')
+ disp('Return with empty oo_.endo_simul.')
+ oo_.endo_simul = [];
+ return
+ end
+
% Disable warnings if homotopy
warning_old_state = warning;
warning off all
diff --git a/matlab/perfect-foresight-models/perfect_foresight_solver_core.m b/matlab/perfect-foresight-models/perfect_foresight_solver_core.m
index 3dac602f66f477cbac967ed8a982ac598f3ca075..a1896890e1325a3a565560dc96ff82b3b89ac1b5 100644
--- a/matlab/perfect-foresight-models/perfect_foresight_solver_core.m
+++ b/matlab/perfect-foresight-models/perfect_foresight_solver_core.m
@@ -75,12 +75,15 @@ else
oo_.deterministic_simulation.status = false;
end
else
- if M_.maximum_endo_lead == 0 && ~options_.lmmcp.status % Purely backward model
+ if M_.maximum_endo_lead == 0 && M_.maximum_endo_lag>0 && ~options_.lmmcp.status % Purely backward model
[oo_.endo_simul, oo_.deterministic_simulation] = ...
sim1_purely_backward(oo_.endo_simul, oo_.exo_simul, oo_.steady_state, M_, options_);
- elseif M_.maximum_endo_lag == 0 && ~options_.lmmcp.status % Purely forward model
- [oo_.endo_simul, oo_.deterministic_simulation] = ...
- sim1_purely_forward(oo_.endo_simul, oo_.exo_simul, oo_.steady_state, M_, options_);
+ elseif M_.maximum_endo_lag == 0 && M_.maximum_endo_lead>0 && ~options_.lmmcp.status % Purely forward model
+ [oo_.endo_simul, oo_.deterministic_simulation] = ...
+ sim1_purely_forward(oo_.endo_simul, oo_.exo_simul, oo_.steady_state, M_, options_);
+ elseif M_.maximum_endo_lag == 0 && M_.maximum_endo_lead == 0 && ~options_.lmmcp.status % Purely static model
+ [oo_.endo_simul, oo_.deterministic_simulation] = ...
+ sim1_purely_static(oo_.endo_simul, oo_.exo_simul, oo_.steady_state, M_, options_);
else % General case
switch options_.stack_solve_algo
case 0
diff --git a/matlab/perfect-foresight-models/sim1_purely_backward.m b/matlab/perfect-foresight-models/sim1_purely_backward.m
index 3f155325f21fe7872143d9d9f8fb31dbdafa30a3..06e5f005c5ae7747fd7cbb808756c61c44f06b53 100644
--- a/matlab/perfect-foresight-models/sim1_purely_backward.m
+++ b/matlab/perfect-foresight-models/sim1_purely_backward.m
@@ -19,15 +19,8 @@ function [endogenousvariables, info] = sim1_purely_backward(endogenousvariables,
% You should have received a copy of the GNU General Public License
% along with Dynare. If not, see <http://www.gnu.org/licenses/>.
-if size(M.lead_lag_incidence,1) > 1
- ny0 = nnz(M.lead_lag_incidence(2,:)); % Number of variables at current period
- nyb = nnz(M.lead_lag_incidence(1,:)); % Number of variables at previous period
- iyb = find(M.lead_lag_incidence(1,:)>0); % Indices of variables at previous period
-else
- ny0 = nnz(M.lead_lag_incidence(1,:)); % Number of variables at current period
- nyb = 0;
- iyb = [];
-end
+ny0 = nnz(M.lead_lag_incidence(2,:)); % Number of variables at current period
+iyb = M.lead_lag_incidence(1,:)>0; % Logical vector (for lagged variables)
if ny0 ~= M.endo_nbr
error('All endogenous variables must appear at the current period!')
@@ -43,13 +36,8 @@ dynamicmodel_s = str2func('dynamic_backward_model_for_simulation');
info.status = true;
for it = M.maximum_lag + (1:options.periods)
- if M.maximum_lag==0 && it==1
- y = endogenousvariables(:,it); % Values at previous period, also used as guess value for current period
- ylag = [];
- else
- y = endogenousvariables(:,it-1); % Values at previous period, also used as guess value for current period
- ylag = y(iyb);
- end
+ y = endogenousvariables(:,it-1); % Values at previous period, also used as guess value for current period
+ ylag = y(iyb);
if ismember(options.solve_algo, [12,14])
[tmp, check] = dynare_solve(dynamicmodel_s, y, options, M.isloggedlhs, M.isauxdiffloggedrhs, M.endo_names, M.lhs, ...
dynamicmodel, ylag, exogenousvariables, M.params, steadystate, it);
diff --git a/matlab/perfect-foresight-models/sim1_purely_static.m b/matlab/perfect-foresight-models/sim1_purely_static.m
new file mode 100644
index 0000000000000000000000000000000000000000..ec03a848a6cef9986b62fbc1e03dfd22d0a86b52
--- /dev/null
+++ b/matlab/perfect-foresight-models/sim1_purely_static.m
@@ -0,0 +1,50 @@
+function [endogenousvariables, info] = sim1_purely_static(endogenousvariables, exogenousvariables, steadystate, M, options)
+
+% Performs deterministic simulation of a purely static model
+
+% Copyright © 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 <http://www.gnu.org/licenses/>.
+
+if nnz(M.lead_lag_incidence(1,:)) ~= M.endo_nbr
+ error('All endogenous variables must appear at the current period!')
+end
+
+if ismember(options.solve_algo, [12,14]) && ~M.possible_to_use_solve_algo_12_14
+ error(M.message_solve_algo_12_14)
+end
+
+dynamicmodel = str2func([M.fname,'.dynamic']);
+dynamicmodel_s = str2func('dynamic_static_model_for_simulation');
+
+info.status = true;
+
+y = endogenousvariables(:,1);
+
+for it = 1:options.periods
+ if ismember(options.solve_algo, [12,14])
+ [tmp, check] = dynare_solve(dynamicmodel_s, y, options, M.isloggedlhs, M.isauxdiffloggedrhs, M.endo_names, M.lhs, ...
+ dynamicmodel, exogenousvariables, M.params, steadystate, it);
+ else
+ [tmp, check] = dynare_solve(dynamicmodel_s, y, options, ...
+ dynamicmodel, exogenousvariables, M.params, steadystate, it);
+ end
+ if check
+ info.status = false;
+ end
+ endogenousvariables(:,it) = tmp;
+ y = endogenousvariables(:,it);
+end
\ No newline at end of file
diff --git a/tests/Makefile.am b/tests/Makefile.am
index 52052c2e27f4d92dfa3bb628446fdb12b8bbd5d6..7f66c697b53afa41c576faf4fd4513b4a67d669f 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -332,6 +332,7 @@ MODFILES = \
deterministic_simulations/purely_forward/ar1.mod \
deterministic_simulations/purely_forward/nk.mod \
deterministic_simulations/purely_backward/ar1.mod \
+ deterministic_simulations/purely_static/toto.mod \
deterministic_simulations/rbc_det1.mod \
deterministic_simulations/rbc_det2.mod \
deterministic_simulations/rbc_det3.mod \
diff --git a/tests/deterministic_simulations/purely_static/toto.mod b/tests/deterministic_simulations/purely_static/toto.mod
new file mode 100644
index 0000000000000000000000000000000000000000..21f76c7028e775a207124884841fc2ffcaededf2
--- /dev/null
+++ b/tests/deterministic_simulations/purely_static/toto.mod
@@ -0,0 +1,25 @@
+var x y;
+
+varexo ex ey;
+
+model;
+ y = x*x/2 + ey;
+ x = ex;
+end;
+
+initval;
+ y = 0;
+ x = 0;
+ ex = 0;
+ ey = 0;
+end;
+
+steady;
+
+shocks;
+ var ex;
+ periods 1 2 3 4;
+ values 1 .5 .25 .125;
+end;
+
+simul(periods=4);