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function [steady_state,params,check] = dyn_ramsey_static(ys_init,M,options_,oo)
% function [steady_state,params,check] = dyn_ramsey_static_(ys_init,M,options_,oo)
% Computes the steady state for optimal policy
%
% INPUTS
% ys_init: vector of endogenous variables or instruments
% M: Dynare model structure
% options: Dynare options structure
% oo: Dynare results structure
%
% OUTPUTS
% steady_state: steady state value
% params: parameters at steady state, potentially updated by
% steady_state file
% check: error indicator, 0 if everything is OK
%
% SPECIAL REQUIREMENTS
% none
% Copyright (C) 2003-2018 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/>.
params = M.params;
check = 0;
options_.steadystate.nocheck = 1; %locally disable checking because Lagrange multipliers are not accounted for in evaluate_steady_state_file
% dyn_ramsey_static_1 is a subfunction
nl_func = @(x) dyn_ramsey_static_1(x,M,options_,oo);
% check_static_model is a subfunction
if check_static_model(ys_init,M,options_,oo) && ~options_.steadystate_flag
steady_state = ys_init;
return
elseif options_.steadystate_flag
k_inst = [];
inst_nbr = size(options_.instruments,1);
for i = 1:inst_nbr
k_inst = [k_inst; strmatch(options_.instruments{i}, M.endo_names, 'exact')];
end
if inst_nbr == 1
%solve for instrument, using univariate solver, starting at initial value for instrument
[inst_val, info1]= csolve(nl_func,ys_init(k_inst),'',options_.solve_tolf,options_.ramsey.maxit);
if info1==1 || info1==3
check=81;
end
if info1==4
check=87;
end
else
%solve for instrument, using multivariate solver, starting at
%initial value for instrument
opt = options_;
opt.jacobian_flag = false;
[inst_val,info1] = dynare_solve(nl_func,ys_init(k_inst), ...
opt);
if info1~=0
check=81;
end
end
ys_init(k_inst) = inst_val;
exo_ss = [oo.exo_steady_state oo.exo_det_steady_state];
[xx,params] = evaluate_steady_state_file(ys_init,exo_ss,M,options_,~options_.steadystate.nocheck); %run steady state file again to update parameters
[~,~,steady_state] = nl_func(inst_val); %compute and return steady state
else
n_var = M.orig_endo_nbr;
xx = oo.steady_state(1:n_var);
opt = options_;
opt.jacobian_flag = false;
[xx,info1] = dynare_solve(nl_func,xx,opt);
if info1~=0
check=81;
end
[~,~,steady_state] = nl_func(xx);
end
function [resids,rJ,steady_state] = dyn_ramsey_static_1(x,M,options_,oo)
resids = [];
rJ = [];
mult = [];
% recovering usefull fields
params = M.params;
endo_nbr = M.endo_nbr;
endo_names = M.endo_names;
orig_endo_nbr = M.orig_endo_nbr;
aux_vars_type = [M.aux_vars.type];
orig_endo_aux_nbr = orig_endo_nbr + min(find(aux_vars_type == 6)) - 1;
orig_eq_nbr = M.orig_eq_nbr;
inst_nbr = orig_endo_aux_nbr - orig_eq_nbr;
% indices of Lagrange multipliers
fname = M.fname;
if options_.steadystate_flag
k_inst = [];
instruments = options_.instruments;
for i = 1:size(instruments,1)
k_inst = [k_inst; strmatch(instruments{i}, endo_names, 'exact')];
end
ys_init=zeros(size(oo.steady_state)); %create starting vector for steady state computation as only instrument value is handed over
ys_init(k_inst) = x; %set instrument, the only value required for steady state computation, to current value
[x,params,check] = evaluate_steady_state_file(ys_init,... %returned x now has size endo_nbr as opposed to input size of n_instruments
[oo.exo_steady_state; ...
oo.exo_det_steady_state], ...
M,options_,~options_.steadystate.nocheck);
if any(imag(x(1:M.orig_endo_nbr))) %return with penalty
resids=ones(inst_nbr,1)+sum(abs(imag(x(1:M.orig_endo_nbr)))); %return with penalty
steady_state=NaN(endo_nbr,1);
return
end
if check %return
resids=ones(inst_nbr,1)+sum(abs(x(1:M.orig_endo_nbr))); %return with penalty
steady_state=NaN(endo_nbr,1);
return
end
end
xx = zeros(endo_nbr,1); %initialize steady state vector
xx(1:M.orig_endo_nbr) = x(1:M.orig_endo_nbr); %set values of original endogenous variables based on steady state file or initial value
% setting steady state of auxiliary variables that depends on original endogenous variables
if any([M.aux_vars.type] ~= 6) %auxiliary variables other than multipliers
needs_set_auxiliary_variables = 1;
if M.set_auxiliary_variables
fh = str2func([M.fname '.set_auxiliary_variables']);
s_a_v_func = @(z) fh(z,...
[oo.exo_steady_state,...
oo.exo_det_steady_state],...
params);
else
s_a_v_func = z;
end
xx = s_a_v_func(xx);
else
needs_set_auxiliary_variables = 0;
end
% value and Jacobian of objective function
ex = zeros(1,M.exo_nbr);
[U,Uy,Uyy] = feval([fname '.objective.static'],x,ex, params);
Uyy = reshape(Uyy,endo_nbr,endo_nbr);
% set multipliers and auxiliary variables that
% depends on multipliers to 0 to compute residuals
if (options_.bytecode)
[chck, res, junk] = bytecode('static',xx,[oo.exo_steady_state oo.exo_det_steady_state], ...
params, 'evaluate');
fJ = junk.g1;
else
[res,fJ] = feval([fname '.static'],xx,[oo.exo_steady_state oo.exo_det_steady_state], ...
params);
end
% index of multipliers and corresponding equations
% the auxiliary variables before the Lagrange multipliers are treated
% as ordinary endogenous variables
aux_eq = [1:orig_endo_aux_nbr, orig_endo_aux_nbr+orig_eq_nbr+1:size(fJ,1)];
A = fJ(1:orig_endo_aux_nbr,orig_endo_nbr+find(aux_vars_type==6));
y = res(1:orig_endo_aux_nbr);
mult = -A\y;
resids1 = y+A*mult;
if inst_nbr == 1
r1 = sqrt(resids1'*resids1);
else
[q,r,e] = qr([A y]');
k = size(A,1)+(1-inst_nbr:0);
r1 = r(end,k)';
end
if options_.steadystate_flag
resids = r1;
else
resids = [res(orig_endo_nbr+(1:orig_endo_nbr-inst_nbr)); r1];
end
rJ = [];
if needs_set_auxiliary_variables
steady_state = s_a_v_func([xx(1:orig_endo_aux_nbr); mult]);
else
steady_state = [xx(1:orig_endo_aux_nbr); mult];
end
function result = check_static_model(ys,M,options_,oo)
result = false;
if (options_.bytecode)
[chck, res, ~] = bytecode('static',ys,[oo.exo_steady_state oo.exo_det_steady_state], ...
M.params, 'evaluate');
else
res = feval([M.fname '.static'],ys,[oo.exo_steady_state oo.exo_det_steady_state], ...
M.params);
end
if norm(res) < options_.solve_tolf
result = true;
end
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