method_of_moments: add irf_matching to objective_function

covariance-quadratic-approximation
Willi Mutschler 2023-10-09 22:33:43 +02:00
parent e9871d7d47
commit 20ec0a6c97
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1 changed files with 83 additions and 4 deletions

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@ -1,7 +1,8 @@
function [fval, info, exit_flag, df, junkHessian, Q, model_moments, model_moments_params_derivs] = objective_function(xparam, data_moments, weighting_info, options_mom_, M_, estim_params_, bayestopt_, BoundsInfo, dr, endo_steady_state, exo_steady_state, exo_det_steady_state)
% [fval, info, exit_flag, df, junkHessian, Q, model_moments, model_moments_params_derivs] = objective_function(xparam, data_moments, weighting_info, options_mom_, M_, estim_params_, bayestopt_, BoundsInfo, dr, endo_steady_state, exo_steady_state, exo_det_steady_state);
function [fval, info, exit_flag, df, junkHessian, Q, model_moments, model_moments_params_derivs, irf_model_varobs] = objective_function(xparam, data_moments, weighting_info, options_mom_, M_, estim_params_, bayestopt_, BoundsInfo, dr, endo_steady_state, exo_steady_state, exo_det_steady_state)
% [fval, info, exit_flag, df, junkHessian, Q, model_moments, model_moments_params_derivs, irf_model_varobs] = objective_function(xparam, data_moments, weighting_info, options_mom_, M_, estim_params_, bayestopt_, BoundsInfo, dr, endo_steady_state, exo_steady_state, exo_det_steady_state)
% -------------------------------------------------------------------------
% This function evaluates the objective function for a method of moments estimation
% This function evaluates the objective function for method of moments estimation,
% i.e. distance between model and data moments/irfs, possibly augmented with priors.
% -------------------------------------------------------------------------
% INPUTS (same ones as in dsge_likelihood.m and dsge_var_likelihood.m)
% - xparam: [vector] current value of estimated parameters as returned by set_prior()
@ -26,6 +27,7 @@ function [fval, info, exit_flag, df, junkHessian, Q, model_moments, model_moment
% - Q: [double] value of the quadratic form of the moment difference
% - model_moments: [vector] model moments
% - model_moments_params_derivs: [matrix] analytical jacobian of the model moments wrt estimated parameters (currently for GMM only)
% - irf_model_varobs: [matrix] model irfs for observable variables (used for plotting matched irfs in mom.run)
% -------------------------------------------------------------------------
% This function is called by
% o mom.run
@ -33,8 +35,12 @@ function [fval, info, exit_flag, df, junkHessian, Q, model_moments, model_moment
% -------------------------------------------------------------------------
% This function calls
% o check_bounds_and_definiteness_estimation
% o get_lower_cholesky_covariance
% o get_perturbation_params_derivs
% o getIrfShocksIndx
% o irf
% o mom.get_data_moments
% o priordens
% o pruned_state_space_system
% o resol
% o set_all_parameters
@ -62,6 +68,7 @@ function [fval, info, exit_flag, df, junkHessian, Q, model_moments, model_moment
%------------------------------------------------------------------------------
% Initialization of the returned variables and others...
%------------------------------------------------------------------------------
irf_model_varobs = [];
model_moments_params_derivs = [];
model_moments = [];
Q = [];
@ -247,12 +254,84 @@ if strcmp(options_mom_.mom.mom_method,'SMM')
end
%------------------------------------------------------------------------------
% IRF_MATCHING using STOCH_SIMUL: Compute irfs given model solution and Cholesky
% decomposition on shock covariance matrix; this resembles the core codes in
% stoch_simul
%------------------------------------------------------------------------------
if strcmp(options_mom_.mom.mom_method,'IRF_MATCHING') && strcmp(options_mom_.mom.simulation_method,'STOCH_SIMUL')
cs = get_lower_cholesky_covariance(M_.Sigma_e,options_mom_.add_tiny_number_to_cholesky);
irf_shocks_indx = getIrfShocksIndx(M_, options_mom_);
modelIrf = nan(options_mom_.irf,M_.endo_nbr,M_.exo_nbr);
for i = irf_shocks_indx
if options_mom_.order>1 && options_mom_.relative_irf % normalize shock to 0.01 before IRF generation for GIRFs; multiply with 100 later
y_irf = irf(M_, options_mom_, dr, cs(:,i)./cs(i,i)/100, options_mom_.irf, options_mom_.drop, options_mom_.replic, options_mom_.order);
else % for linear model, rescaling is done later
y_irf = irf(M_, options_mom_, dr, cs(:,i), options_mom_.irf, options_mom_.drop, options_mom_.replic, options_mom_.order);
end
if any(any(isnan(y_irf))) && ~options_mom_.pruning && ~(options_mom_.order==1)
fprintf('\nirf_matching: The simulations conducted for generating IRFs to %s were explosive: Either reduce the shock size, use pruning, or set the approximation order to 1.\n', M_.exo_names{i})
fval = Inf;
info(1) = 180;
info(4) = 0.1;
exit_flag = 0;
if options_mom_.mom.vector_output == 1 % lsqnonlin requires vector output
fval = ones(options_mom_.mom.mom_nbr,1)*options_mom_.huge_number;
end
return
end
if options_mom_.relative_irf
if options_mom_.order==1 % multiply with 100 for backward compatibility
y_irf = 100*y_irf/cs(i,i);
end
end
modelIrf(:,:,i) = transpose(y_irf);
end
% do transformations on model irfs if irf_matching_file is provided
if ~isempty(options_mom_.mom.irf_matching_file.name)
[modelIrf,check] = feval(str2func(options_mom_.mom.irf_matching_file.name),modelIrf, M_, options_mom_);
if check
fval = Inf;
info(1) = 180;
info(4) = 0.1;
exit_flag = 0;
if options_mom_.mom.vector_output == 1 % lsqnonlin requires vector output
fval = ones(options_mom_.mom.mom_nbr,1)*options_mom_.huge_number;
end
return
end
end
irf_model_varobs = modelIrf(:,options_mom_.varobs_id,:); % focus only on observables (this will be used later for plotting)
model_moments = irf_model_varobs(options_mom_.mom.irfIndex); % focus only on selected irf periods
end
%--------------------------------------------------------------------------
% Compute quadratic target function
%--------------------------------------------------------------------------
moments_difference = data_moments - model_moments;
if strcmp(options_mom_.mom.mom_method,'GMM') || strcmp(options_mom_.mom.mom_method,'SMM')
if strcmp(options_mom_.mom.mom_method,'IRF_MATCHING')
Q = transpose(moments_difference)*weighting_info.W*moments_difference;
% log-likelihood
lnlik = options_mom_.mom.mom_nbr/2*log(1/2/pi) - 1/2*weighting_info.Winv_logdet - 1/2*Q;
if isinf(lnlik)
fval = Inf; info(1) = 50; info(4) = 0.1; exit_flag = 0;
return
end
if isnan(lnlik)
fval = Inf; info(1) = 45; info(4) = 0.1; exit_flag = 0;
return
end
if imag(lnlik)~=0
fval = Inf; info(1) = 46; info(4) = 0.1; exit_flag = 0;
return
end
% add log prior if necessary
lnprior = priordens(xparam,bayestopt_.pshape,bayestopt_.p6,bayestopt_.p7,bayestopt_.p3,bayestopt_.p4);
fval = - (lnlik + lnprior);
elseif strcmp(options_mom_.mom.mom_method,'GMM') || strcmp(options_mom_.mom.mom_method,'SMM')
residuals = sqrt(options_mom_.mom.weighting_matrix_scaling_factor)*weighting_info.Sw*moments_difference;
Q = residuals'*residuals;
if options_mom_.mom.vector_output == 1 % lsqnonlin requires vector output