186 lines
6.3 KiB
Matlab
186 lines
6.3 KiB
Matlab
function perfect_foresight_solver()
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% Computes deterministic simulations
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%
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% INPUTS
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% None
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%
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% OUTPUTS
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% none
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%
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% ALGORITHM
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%
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% SPECIAL REQUIREMENTS
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% none
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% Copyright (C) 1996-2015 Dynare Team
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%
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% This file is part of Dynare.
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%
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% Dynare is free software: you can redistribute it and/or modify
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% it under the terms of the GNU General Public License as published by
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% the Free Software Foundation, either version 3 of the License, or
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% (at your option) any later version.
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%
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% Dynare is distributed in the hope that it will be useful,
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% but WITHOUT ANY WARRANTY; without even the implied warranty of
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% MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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% GNU General Public License for more details.
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%
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% You should have received a copy of the GNU General Public License
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% along with Dynare. If not, see <http://www.gnu.org/licenses/>.
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global M_ options_ oo_
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check_input_arguments(options_, M_, oo_);
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if isempty(options_.scalv) || options_.scalv == 0
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options_.scalv = oo_.steady_state;
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end
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options_.scalv= 1;
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if options_.debug
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model_static = str2func([M_.fname,'_static']);
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for ii=1:size(oo_.exo_simul,1)
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[residual(:,ii)] = model_static(oo_.steady_state, oo_.exo_simul(ii,:),M_.params);
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end
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problematic_periods=find(any(isinf(residual)) | any(isnan(residual)))-M_.maximum_endo_lag;
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if ~isempty(problematic_periods)
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period_string=num2str(problematic_periods(1));
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for ii=2:length(problematic_periods)
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period_string=[period_string, ', ', num2str(problematic_periods(ii))];
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end
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fprintf('\n\nWARNING: Value for the exogenous variable(s) in period(s) %s inconsistent with the static model.\n',period_string);
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fprintf('WARNING: Check for division by 0.\n')
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end
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end
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initperiods = 1:M_.maximum_lag;
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lastperiods = (M_.maximum_lag+options_.periods+1):(M_.maximum_lag+options_.periods+M_.maximum_lead);
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oo_ = perfect_foresight_solver_core(M_,options_,oo_);
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% If simulation failed try homotopy.
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if ~oo_.deterministic_simulation.status && ~options_.no_homotopy
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skipline()
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disp('Simulation of the perfect foresight model failed!')
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disp('Switching to a homotopy method...')
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if ~M_.maximum_lag
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disp('Homotopy not implemented for purely forward models!')
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disp('Failed to solve the model!')
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disp('Return with empty oo_.endo_simul.')
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oo_.endo_simul = [];
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skipline()
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return
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end
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if ~M_.maximum_lead
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disp('Homotopy not implemented for purely backward models!')
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disp('Failed to solve the model!')
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disp('Return with empty oo_.endo_simul.')
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oo_.endo_simul = [];
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skipline()
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return
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end
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skipline()
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% Disable warnings if homotopy
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warning_old_state = warning;
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warning off all
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% Do not print anything
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oldverbositylevel = options_.verbosity;
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options_.verbosity = 0;
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exosim = oo_.exo_simul;
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exoinit = repmat(oo_.exo_steady_state',M_.maximum_lag+options_.periods+M_.maximum_lead,1);
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endosim = oo_.endo_simul;
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endoinit = repmat(oo_.steady_state, 1,M_.maximum_lag+options_.periods+M_.maximum_lead);
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current_weight = 0; % Current weight of target point in convex combination
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step = .5;
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success_counter = 0;
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iteration = 0;
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fprintf('Iter. \t | Lambda \t | status \t | Max. residual\n')
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fprintf('++++++++++++++++++++++++++++++++++++++++++++++++++++++++\n')
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while (step > options_.dynatol.x)
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if ~isequal(step,1)
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options_.verbosity = 0;
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end
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iteration = iteration+1;
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new_weight = current_weight + step; % Try this weight, and see if it succeeds
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if new_weight >= 1
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new_weight = 1; % Don't go beyond target point
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step = new_weight - current_weight;
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end
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% Compute convex combination for exo path and initial/terminal endo conditions
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% But take care of not overwriting the computed part of oo_.endo_simul
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oo_.exo_simul = exosim*new_weight + exoinit*(1-new_weight);
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oo_.endo_simul(:,[initperiods, lastperiods]) = ...
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new_weight*oo_.endo_simul(:,[initperiods, lastperiods])+(1-new_weight)*endoinit(:,[initperiods, lastperiods]);
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path_with_nans = any(any(isnan(oo_.endo_simul)));
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path_with_cplx = any(any(~isreal(oo_.endo_simul)));
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if isequal(iteration,1)
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oo_.endo_simul(:,M_.maximum_lag+1:end-M_.maximum_lead) = endoinit(:,1:options_.periods);
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elseif path_with_nans || path_with_cplx
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oo_.endo_simul(:,M_.maximum_lag+1:end-M_.maximum_lead) = saved_endo_simul(:,1+M_.maximum_lag:end-M_.maximum_lead);
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end
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saved_endo_simul = oo_.endo_simul;
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[oo_,me] = perfect_foresight_solver_core(M_,options_,oo_);
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if oo_.deterministic_simulation.status == 1
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current_weight = new_weight;
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if current_weight >= 1
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fprintf('%i \t | %1.5f \t | %s \t | %e\n', iteration, new_weight, 'succeeded', me)
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break
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end
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success_counter = success_counter + 1;
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if success_counter >= 3
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success_counter = 0;
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step = step * 2;
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end
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fprintf('%i \t | %1.5f \t | %s \t | %e\n', iteration, new_weight, 'succeeded', me)
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else
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oo_.endo_simul = saved_endo_simul;
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success_counter = 0;
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step = step / 2;
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if isreal(me)
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fprintf('%i \t | %1.5f \t | %s \t | %e\n', iteration, new_weight, 'failed', me)
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else
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fprintf('%i \t | %1.5f \t | %s \t | %s\n', iteration, new_weight, 'failed', 'Complex')
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end
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end
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end
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fprintf('++++++++++++++++++++++++++++++++++++++++++++++++++++++++\n')
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skipline()
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options_.verbosity = oldverbositylevel;
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warning(warning_old_state);
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end
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if oo_.deterministic_simulation.status == 1
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disp('Perfect foresight solution found.')
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skipline()
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else
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warning('Failed to solve perfect foresight model')
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end
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dyn2vec;
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if ~isdates(options_.initial_period) && isnan(options_.initial_period)
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initial_period = dates(1,1);
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else
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initial_period = options_.initial_period;
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end
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ts = dseries(transpose(oo_.endo_simul),initial_period,cellstr(M_.endo_names));
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assignin('base', 'Simulated_time_series', ts);
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