Added routines for VAR_EXPECTATION_MODEL.

time-shift
Stéphane Adjemian(Charybdis) 2018-08-08 15:53:55 +02:00
parent 988015e6a3
commit 8033b2737e
2 changed files with 203 additions and 0 deletions

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function DynareModel = parameters(varexpectationmodelname, DynareModel, DynareOutput)
% Updates the VAR expectation reduced form parameters.
%
% INPUTS
% - varexpectationmodelname [string] Name of the pac equation.
% - DynareModel [struct] M_ global structure (model properties)
% - DynareOutput [struct] oo_ global structure (model results)
%
% OUTPUTS
% - DynareModel [struct] M_ global structure (with updated params field)
%
% SPECIAL REQUIREMENTS
% none
% Copyright (C) 2018 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/>.
% Check that the first input is a row character array.
if ~isrow(varexpectationmodelname)==1 || ~ischar(varexpectationmodelname)
error('First input argument must be a row character array!')
end
% Check that the model exists.
if ~isfield(DynareModel.var_expectation, varexpectationmodelname)
error('VAR_EXPECTATION_MODEL %s is not defined!', varexpectationmodelname)
end
% Get the VAR model description
varexpectationmodel = DynareModel.var_expectation.(varexpectationmodelname);
% Get the name of the associated VAR model and test its existence.
if ~isfield(DynareModel.var, varexpectationmodel.var_model_name)
error('Unknown VAR (%s) in VAR_EXPECTATION_MODEL (%s)!', varexpectationmodel.var_model_name, varexpectationmodelname)
end
varmodel = DynareModel.var.(varexpectationmodel.var_model_name);
% Check that we have the values of the VAR matrices.
if ~isfield(DynareOutput.var, varexpectationmodel.var_model_name)
error('VAR model %s has to be estimated or calibrated first!', varexpectationmodel.var_model_name)
end
varcalib = DynareOutput.var.(varexpectationmodel.var_model_name);
if ~isfield(varcalib, 'CompanionMatrix') || any(isnan(varcalib.CompanionMatrix(:)))
message = sprintf('VAR model %s has to be estimated first.', varexpectationmodel.var_model_name);
message = sprintf('s\nPlease use get_companion_matrix command first.', message);
error(message)
end
% Set discount factor
if isfield(varexpectationmodel, 'discount_value')
discountfactor = varexpectationmodel.discount_value;
else
if isfield(varexpectationmodel, 'discount_index')
discountfactor = DynareModel.params(varexpectationmodel.discount_index);
else
error('This is most likely a bug. Pleasse conntact the Dynare Team.')
end
end
% A discount factor has to be positive.
if discountfactor<=0
error('The discount factor must be positive.')
end
% A discount factor cannot be greater than one.
if discountfactor>1
error('The discount cannot be greater than one.')
end
% Set variable_id in VAR model
variable_id_in_var = find(varexpectationmodel.variable_id==varmodel.lhs);
% Get the horizon parameter.
horizon = varexpectationmodel.horizon;
% Check the horizon parameter
wrong_horizon_parameter = true;
if length(horizon)==1
if isnumeric(horizon)
if isfinite(horizon)
if isint(horizon)
if horizon>0
wrong_horizon_parameter = false;
end
end
end
end
elseif length(horizon)==2
if isnumeric(horizon)
if isfinite(horizon(1))
if isint(horizon(1))
if horizon(1)>=0
if isinf(horizon(2)) || (isint(horizon(2)) && horizon(2)>horizon(1))
wrong_horizon_parameter = false;
end
end
end
end
end
end
if wrong_horizon_parameter
error('horizon must be an integer scalar or an integer vector with two elements.')
end
% Get the companion matrix
CompanionMatrix = varcalib.CompanionMatrix;
% Get the dimension of the problem.
n = length(CompanionMatrix);
% Set the selection vector
alpha = zeros(1, length(CompanionMatrix));
alpha(variable_id_in_var) = 1;
if length(horizon)==1
% Compute the reduced form parameters of the (discounted) forecast in period t+horizon(1)
if varexpectationmodel.horizon==1
parameters = discountfactor*(alpha*CompanionMatrix);
elseif horizon>1
parameters = alpha*mpower(discountfactor*CompanionMatrix, varexpectationmodel.horizon);
end
else
% Compute the reduced form parameters of the discounted sum of forecasts between t+horizon(1) and
% t+horizon(2). Not that horzizon(2) need not be finite.
if horizon(1)==0 && isinf(horizon(2))
parameters = alpha/(eye(n)-discountfactor*CompanionMatrix);
elseif horizon(1)>0 && isinf(horizon(2))
% Define the discounted companion matrix
DiscountedCompanionMatrix = discountfactor*CompanionMatrix;
% First compute the parameters implied by the discounted sum from h=0 to h=horizon(1)-1
tmp1 = eye(n);
for h=1:horizon(1)
tmp1 = tmp1 + mpower(DiscountedCompanionMatrix, h);
end
tmp1 = alpha*tmp1;
% Second compute the parameters implied by the discounted sum from h=0 to h=Inf
tmp2 = alpha/(eye(n)-DiscountedCompanionMatrix);
% Finally
parameters = tmp2-tmp1;
elseif isfinite(horizon(2))
% Define the discounted companion matrix
DiscountedCompanionMatrix = discountfactor*CompanionMatrix;
tmp = zeros(n);
for h=horizon(1):horizon(2)
tmp = tmp + mpower(DiscountedCompanionMatrix, h);
end
parameters = alpha*tmp;
end
end
% Update reduced form parameters in M_.params.
DynareModel.params(varexpectationmodel.param_indices) = parameters;

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function update(varexpectationmodelname)OA
% Updates the parameters of a VAR_EXPECTATION_MODEL.
%
% INPUTS
% - varepxpectationmodelname [string] Name of the VAR expectation model.
%
% OUTPUTS
% - none
%
% SPECIAL REQUIREMENTS
% none
% Copyright (C) 2018 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/>.
global M_ oo_
M_ = var_expectation.update.parameters(varexpectationmodelname, M_, oo_);