dynare/matlab/irf.m

32 lines
916 B
Matlab

function y = irf(dr, e1, long, drop, replic, iorder)
global M_ oo_ options_
temps = repmat(dr.ys,1,M_.maximum_lag);
y = 0;
if iorder == 1
y1 = repmat(dr.ys,1,long);
ex2 = zeros(long,M_.exo_nbr);
ex2(1,:) = e1';
y2 = simult_(temps,dr,ex2,iorder);
y = y2(:,M_.maximum_lag+1:end)-y1;
else
% eliminate shocks with 0 variance
i_exo_var = setdiff([1:M_.exo_nbr],find(diag(M_.Sigma_e) == 0 ));
nxs = length(i_exo_var);
ex1 = zeros(long+drop,M_.exo_nbr);
ex2 = ex1;
chol_S = chol(M_.Sigma_e(i_exo_var,i_exo_var));
for j = 1: replic
randn('seed',j);
ex1(:,i_exo_var) = randn(long+drop,nxs)*chol_S;
ex2 = ex1;
ex2(drop+1,:) = ex2(drop+1,:)+e1';
y1 = simult_(temps,dr,ex1,iorder);
y2 = simult_(temps,dr,ex2,iorder);
y = y+(y2(:,M_.maximum_lag+drop+1:end)-y1(:,M_.maximum_lag+drop+1:end));
end
y=y/replic;
end