dynare/matlab/dynare_identification.m

572 lines
21 KiB
Matlab
Raw Normal View History

function [pdraws, TAU, GAM, LRE, gp, H, JJ] = dynare_identification(options_ident, pdraws0)
% main
%
% Copyright (C) 2010 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_ options_ oo_ bayestopt_ estim_params_
if exist('OCTAVE_VERSION')
warning('off', 'Octave:divide-by-zero')
else
warning off MATLAB:dividebyzero
end
options_ident = set_default_option(options_ident,'load_ident_files',0);
options_ident = set_default_option(options_ident,'useautocorr',1);
options_ident = set_default_option(options_ident,'ar',3);
options_ident = set_default_option(options_ident,'prior_mc',2000);
if nargin==2,
options_ident.prior_mc=size(pdraws0,1);
end
iload = options_ident.load_ident_files;
nlags = options_ident.ar;
useautocorr = options_ident.useautocorr;
options_.ar=nlags;
options_.prior_mc = options_ident.prior_mc;
options_.options_ident = options_ident;
options_.Schur_vec_tol = 1.e-8;
options_ = set_default_option(options_,'datafile',[]);
options_.mode_compute = 0;
[data,rawdata]=dynare_estimation_init([],1);
% computes a first linear solution to set up various variables
SampleSize = options_ident.prior_mc;
% results = prior_sampler(0,M_,bayestopt_,options_,oo_);
prior_draw(1,bayestopt_);
if ~(exist('sylvester3mr','file')==2),
dynareroot = strrep(which('dynare'),'dynare.m','');
addpath([dynareroot 'gensylv'])
end
IdentifDirectoryName = CheckPath('identification');
indx = estim_params_.param_vals(:,1);
indexo=[];
if ~isempty(estim_params_.var_exo)
indexo = estim_params_.var_exo(:,1);
end
nparam = length(bayestopt_.name);
MaxNumberOfBytes=options_.MaxNumberOfBytes;
if iload <=0,
iteration = 0;
burnin_iteration = 0;
loop_indx = 0;
file_index = 0;
run_index = 0;
h = waitbar(0,'Monte Carlo identification checks ...');
[I,J]=find(M_.lead_lag_incidence');
while iteration < SampleSize,
loop_indx = loop_indx+1;
if nargin==2,
if burnin_iteration>=50,
params = pdraws0(iteration+1,:);
else
params = pdraws0(burnin_iteration+1,:);
end
else
params = prior_draw();
end
set_all_parameters(params);
[A,B,ys,info]=dynare_resolve;
if info(1)==0,
oo0=oo_;
% [Aa,Bb] = kalman_transition_matrix(oo0.dr, ...
% bayestopt_.restrict_var_list, ...
% bayestopt_.restrict_columns, ...
% bayestopt_.restrict_aux, M_.exo_nbr);
% tau=[vec(Aa); dyn_vech(Bb*M_.Sigma_e*Bb')];
tau=[oo_.dr.ys(oo_.dr.order_var); vec(A); dyn_vech(B*M_.Sigma_e*B')];
yy0=oo_.dr.ys(I);
[residual, g1 ] = feval([M_.fname,'_dynamic'],yy0, oo_.exo_steady_state', M_.params,1);
if burnin_iteration<50,
burnin_iteration = burnin_iteration + 1;
pdraws(burnin_iteration,:) = params;
TAU(:,burnin_iteration)=tau;
LRE(:,burnin_iteration)=[oo_.dr.ys(oo_.dr.order_var); vec(g1)];
[gam,stationary_vars] = th_autocovariances(oo0.dr,bayestopt_.mfys,M_,options_);
if exist('OCTAVE_VERSION')
warning('off', 'Octave:divide-by-zero')
else
warning off MATLAB:dividebyzero
end
sdy = sqrt(diag(gam{1}));
sy = sdy*sdy';
if useautocorr,
sy=sy-diag(diag(sy))+eye(length(sy));
gam{1}=gam{1}./sy;
else
for j=1:nlags,
gam{j+1}=gam{j+1}.*sy;
end
end
dum = dyn_vech(gam{1});
for j=1:nlags,
dum = [dum; vec(gam{j+1})];
end
GAM(:,burnin_iteration)=[oo_.dr.ys(bayestopt_.mfys); dum];
warning warning_old_state;
else
iteration = iteration + 1;
run_index = run_index + 1;
if iteration==1,
indJJ = (find(std(GAM')>1.e-8));
indH = (find(std(TAU')>1.e-8));
indLRE = (find(std(LRE')>1.e-8));
TAU = zeros(length(indH),SampleSize);
GAM = zeros(length(indJJ),SampleSize);
LRE = zeros(length(indLRE),SampleSize);
MAX_tau = min(SampleSize,ceil(MaxNumberOfBytes/(length(indH)*nparam)/8));
MAX_gam = min(SampleSize,ceil(MaxNumberOfBytes/(length(indJJ)*nparam)/8));
stoH = zeros([length(indH),nparam,MAX_tau]);
stoJJ = zeros([length(indJJ),nparam,MAX_tau]);
delete([IdentifDirectoryName '/' M_.fname '_identif_*.mat'])
end
end
if iteration,
TAU(:,iteration)=tau(indH);
vg1 = [oo_.dr.ys(oo_.dr.order_var); vec(g1)];
LRE(:,iteration)=vg1(indLRE);
[JJ, H, gam, gp] = getJJ(A, B, M_,oo0,options_,0,indx,indexo,bayestopt_.mf2,nlags,useautocorr);
GAM(:,iteration)=gam(indJJ);
stoLRE(:,:,run_index) = gp(indLRE,:);
stoH(:,:,run_index) = H(indH,:);
stoJJ(:,:,run_index) = JJ(indJJ,:);
% use relative changes
% siJ = abs(JJ(indJJ,:).*(1./gam(indJJ)*params));
% siH = abs(H(indH,:).*(1./tau(indH)*params));
% use prior uncertainty
siJ = (JJ(indJJ,:));
siH = (H(indH,:));
siLRE = (gp(indLRE,:));
% siJ = abs(JJ(indJJ,:).*(ones(length(indJJ),1)*bayestopt_.p2'));
% siH = abs(H(indH,:).*(ones(length(indH),1)*bayestopt_.p2'));
% siJ = abs(JJ(indJJ,:).*(1./mGAM'*bayestopt_.p2'));
% siH = abs(H(indH,:).*(1./mTAU'*bayestopt_.p2'));
if iteration ==1,
siJmean = abs(siJ)./SampleSize;
siHmean = abs(siH)./SampleSize;
siLREmean = abs(siLRE)./SampleSize;
derJmean = (siJ)./SampleSize;
derHmean = (siH)./SampleSize;
derLREmean = (siLRE)./SampleSize;
else
siJmean = abs(siJ)./SampleSize+siJmean;
siHmean = abs(siH)./SampleSize+siHmean;
siLREmean = abs(siLRE)./SampleSize+siLREmean;
derJmean = (siJ)./SampleSize+derJmean;
derHmean = (siH)./SampleSize+derHmean;
derLREmean = (siLRE)./SampleSize+derLREmean;
end
pdraws(iteration,:) = params;
[idemodel.Mco(:,iteration), idemoments.Mco(:,iteration), idelre.Mco(:,iteration), ...
idemodel.Pco(:,:,iteration), idemoments.Pco(:,:,iteration), idelre.Pco(:,:,iteration), ...
idemodel.cond(iteration), idemoments.cond(iteration), idelre.cond(iteration), ...
idemodel.ee(:,:,iteration), idemoments.ee(:,:,iteration), idelre.ee(:,:,iteration), ...
idemodel.ind(:,iteration), idemoments.ind(:,iteration), ...
idemodel.indno{iteration}, idemoments.indno{iteration}] = ...
identification_checks(H(indH,:),JJ(indJJ,:), gp(indLRE,:), bayestopt_);
if run_index==MAX_tau | iteration==SampleSize,
file_index = file_index + 1;
if run_index<MAX_tau,
stoH = stoH(:,:,1:run_index);
stoJJ = stoJJ(:,:,1:run_index);
stoLRE = stoLRE(:,:,1:run_index);
end
save([IdentifDirectoryName '/' M_.fname '_identif_' int2str(file_index)], 'stoH', 'stoJJ', 'stoLRE')
run_index = 0;
end
waitbar(iteration/SampleSize,h,['MC Identification, iteration ',int2str(iteration),'/',int2str(SampleSize)])
end
end
end
close(h)
save([IdentifDirectoryName '/' M_.fname '_identif'], 'pdraws', 'idemodel', 'idemoments', 'idelre', 'indJJ', 'indH', 'indLRE', ...
'siHmean', 'siJmean', 'siLREmean', 'derHmean', 'derJmean', 'derLREmean', 'TAU', 'GAM', 'LRE')
else
load([IdentifDirectoryName '/' M_.fname '_identif'], 'pdraws', 'idemodel', 'idemoments', 'idelre', 'indJJ', 'indH', 'indLRE', ...
'siHmean', 'siJmean', 'siLREmean', 'derHmean', 'derJmean', 'derLREmean', 'TAU', 'GAM', 'LRE')
options_ident.prior_mc=size(pdraws,1);
SampleSize = options_ident.prior_mc;
options_.options_ident = options_ident;
end
offset = estim_params_.nvx;
offset = offset + estim_params_.nvn;
offset = offset + estim_params_.ncx;
offset = offset + estim_params_.ncn;
siJmean = siJmean.*(ones(length(indJJ),1)*std(pdraws));
siHmean = siHmean.*(ones(length(indH),1)*std(pdraws));
siLREmean = siLREmean.*(ones(length(indLRE),1)*std(pdraws(:, offset+1:end )));
derJmean = derJmean.*(ones(length(indJJ),1)*std(pdraws));
derHmean = derHmean.*(ones(length(indH),1)*std(pdraws));
derLREmean = derLREmean.*(ones(length(indLRE),1)*std(pdraws(:, offset+1:end )));
derHmean = abs(derHmean./(max(siHmean')'*ones(1,size(pdraws,2))));
derJmean = abs(derJmean./(max(siJmean')'*ones(1,size(pdraws,2))));
derLREmean = abs(derLREmean./(max(siLREmean')'*ones(1,estim_params_.np)));
siHmean = siHmean./(max(siHmean')'*ones(1,size(pdraws,2)));
siJmean = siJmean./(max(siJmean')'*ones(1,size(pdraws,2)));
siLREmean = siLREmean./(max(siLREmean')'*ones(1,estim_params_.np));
tstJmean = derJmean*0;
tstHmean = derHmean*0;
tstLREmean = derLREmean*0;
if exist('OCTAVE_VERSION')
warning('off', 'Octave:divide-by-zero')
else
warning off MATLAB:dividebyzero
end
for j=1:nparam,
indd = 1:length(siJmean(:,j));
tstJmean(indd,j) = abs(derJmean(indd,j))./siJmean(indd,j);
indd = 1:length(siHmean(:,j));
tstHmean(indd,j) = abs(derHmean(indd,j))./siHmean(indd,j);
if j>offset
indd = 1:length(siLREmean(:,j-offset));
tstLREmean(indd,j-offset) = abs(derLREmean(indd,j-offset))./siLREmean(indd,j-offset);
end
end
if nargout>3 & iload,
filnam = dir([IdentifDirectoryName '/' M_.fname '_identif_*.mat']);
H=[];
JJ = [];
gp = [];
for j=1:length(filnam),
load([IdentifDirectoryName '/' M_.fname '_identif_',int2str(j),'.mat']);
H = cat(3,H, stoH(:,abs(iload),:));
JJ = cat(3,JJ, stoJJ(:,abs(iload),:));
gp = cat(3,gp, stoLRE(:,abs(iload),:));
end
end
% mTAU = mean(TAU');
% mGAM = mean(GAM');
% sTAU = std(TAU');
% sGAM = std(GAM');
% if nargout>=3,
% GAM0=GAM;
% end
% if useautocorr,
% idiag = find(dyn_vech(eye(size(options_.varobs,1))));
% GAM(idiag,:) = GAM(idiag,:)./(sGAM(idiag)'*ones(1,SampleSize));
% % siJmean(idiag,:) = siJmean(idiag,:)./(sGAM(idiag)'*ones(1,nparam));
% % siJmean = siJmean./(max(siJmean')'*ones(size(params)));
% end
%
% [pcc, dd] = eig(cov(GAM'));
% [latent, isort] = sort(-diag(dd));
% latent = -latent;
% pcc=pcc(:,isort);
% siPCA = (siJmean'*abs(pcc')).^2';
% siPCA = siPCA./(max(siPCA')'*ones(1,nparam)).*(latent*ones(1,nparam));
% siPCA = sum(siPCA,1);
% siPCA = siPCA./max(siPCA);
%
% [pcc, dd] = eig(corrcoef(GAM'));
% [latent, isort] = sort(-diag(dd));
% latent = -latent;
% pcc=pcc(:,isort);
% siPCA2 = (siJmean'*abs(pcc')).^2';
% siPCA2 = siPCA2./(max(siPCA2')'*ones(1,nparam)).*(latent*ones(1,nparam));
% siPCA2 = sum(siPCA2,1);
% siPCA2 = siPCA2./max(siPCA2);
%
% [pcc, dd] = eig(cov(TAU'));
% [latent, isort] = sort(-diag(dd));
% latent = -latent;
% pcc=pcc(:,isort);
% siHPCA = (siHmean'*abs(pcc')).^2';
% siHPCA = siHPCA./(max(siHPCA')'*ones(1,nparam)).*(latent*ones(1,nparam));
% siHPCA = sum(siHPCA,1);
% siHPCA = siHPCA./max(siHPCA);
%
% [pcc, dd] = eig(corrcoef(TAU'));
% [latent, isort] = sort(-diag(dd));
% latent = -latent;
% pcc=pcc(:,isort);
% siHPCA2 = (siHmean'*abs(pcc')).^2';
% siHPCA2 = siHPCA2./(max(siHPCA2')'*ones(1,nparam)).*(latent*ones(1,nparam));
% siHPCA2 = sum(siHPCA2,1);
% siHPCA2 = siHPCA2./max(siHPCA2);
disp_identification(pdraws, idemodel, idemoments)
% figure,
% % myboxplot(siPCA(1:(max(find(cumsum(latent)./length(indJJ)<0.99))+1),:))
% subplot(221)
% bar(siHPCA)
% % set(gca,'ylim',[0 1])
% set(gca,'xticklabel','')
% set(gca,'xlim',[0.5 nparam+0.5])
% for ip=1:nparam,
% text(ip,-0.02,bayestopt_.name{ip},'rotation',90,'HorizontalAlignment','right','interpreter','none')
% end
% title('Sensitivity in TAU''s PCA')
%
% subplot(222)
% % myboxplot(siPCA(1:(max(find(cumsum(latent)./length(indJJ)<0.99))+1),:))
% bar(siHPCA2)
% % set(gca,'ylim',[0 1])
% set(gca,'xticklabel','')
% set(gca,'xlim',[0.5 nparam+0.5])
% for ip=1:nparam,
% text(ip,-0.02,bayestopt_.name{ip},'rotation',90,'HorizontalAlignment','right','interpreter','none')
% end
% title('Sensitivity in standardized TAU''s PCA')
%
%
% subplot(223)
% % myboxplot(siPCA(1:(max(find(cumsum(latent)./length(indJJ)<0.99))+1),:))
% bar(siPCA)
% % set(gca,'ylim',[0 1])
% set(gca,'xticklabel','')
% set(gca,'xlim',[0.5 nparam+0.5])
% for ip=1:nparam,
% text(ip,-0.02,bayestopt_.name{ip},'rotation',90,'HorizontalAlignment','right','interpreter','none')
% end
% title('Sensitivity in moments'' PCA')
%
% subplot(224)
% % myboxplot(siPCA(1:(max(find(cumsum(latent)./length(indJJ)<0.99))+1),:))
% bar(siPCA2)
% % set(gca,'ylim',[0 1])
% set(gca,'xticklabel','')
% set(gca,'xlim',[0.5 nparam+0.5])
% for ip=1:nparam,
% text(ip,-0.02,bayestopt_.name{ip},'rotation',90,'HorizontalAlignment','right','interpreter','none')
% end
% title('Sensitivity in standardized moments'' PCA')
figure('Name','Identification LRE model form'),
subplot(211)
mmm = mean(siLREmean);
[ss, is] = sort(mmm);
myboxplot(siLREmean(:,is))
set(gca,'ylim',[0 1.05])
set(gca,'xticklabel','')
for ip=1:estim_params_.np,
text(ip,-0.02,deblank(M_.param_names(estim_params_.param_vals(is(ip),1),:)),'rotation',90,'HorizontalAlignment','right','interpreter','none')
end
title('Sensitivity in the LRE model')
subplot(212)
mmm = mean(-idelre.Mco');
[ss, is] = sort(mmm);
myboxplot(idelre.Mco(is,:)')
set(gca,'ylim',[0 1])
set(gca,'xticklabel','')
for ip=1:estim_params_.np,
text(ip,-0.02,deblank(M_.param_names(estim_params_.param_vals(is(ip),1),:)),'rotation',90,'HorizontalAlignment','right','interpreter','none')
end
title('Multicollinearity in the LRE model')
saveas(gcf,[IdentifDirectoryName,'/',M_.fname,'_ident_LRE'])
eval(['print -depsc2 ' IdentifDirectoryName '/' M_.fname '_ident_LRE']);
eval(['print -dpdf ' IdentifDirectoryName '/' M_.fname '_ident_LRE']);
if options_.nograph, close(gcf); end
figure('Name','Identification in the model'),
subplot(211)
mmm = mean(siHmean);
[ss, is] = sort(mmm);
myboxplot(siHmean(:,is))
set(gca,'ylim',[0 1.05])
set(gca,'xticklabel','')
for ip=1:nparam,
text(ip,-0.02,bayestopt_.name{is(ip)},'rotation',90,'HorizontalAlignment','right','interpreter','none')
end
title('Sensitivity in the model')
subplot(212)
mmm = mean(-idemodel.Mco');
[ss, is] = sort(mmm);
myboxplot(idemodel.Mco(is,:)')
set(gca,'ylim',[0 1])
set(gca,'xticklabel','')
for ip=1:nparam,
text(ip,-0.02,bayestopt_.name{is(ip)},'rotation',90,'HorizontalAlignment','right','interpreter','none')
end
title('Multicollinearity in the model')
saveas(gcf,[IdentifDirectoryName,'/',M_.fname,'_ident_model'])
eval(['print -depsc2 ' IdentifDirectoryName '/' M_.fname '_ident_model']);
eval(['print -dpdf ' IdentifDirectoryName '/' M_.fname '_ident_model']);
if options_.nograph, close(gcf); end
figure('Name','Identification in the moments'),
subplot(211)
mmm = mean(siJmean);
[ss, is] = sort(mmm);
myboxplot(siJmean(:,is))
set(gca,'ylim',[0 1.05])
set(gca,'xticklabel','')
for ip=1:nparam,
text(ip,-0.02,bayestopt_.name{is(ip)},'rotation',90,'HorizontalAlignment','right','interpreter','none')
end
title('Sensitivity in the moments')
subplot(212)
mmm = mean(-idemoments.Mco');
[ss, is] = sort(mmm);
myboxplot(idemoments.Mco(is,:)')
set(gca,'ylim',[0 1])
set(gca,'xticklabel','')
for ip=1:nparam,
text(ip,-0.02,bayestopt_.name{is(ip)},'rotation',90,'HorizontalAlignment','right','interpreter','none')
end
title('Multicollinearity in the moments')
saveas(gcf,[IdentifDirectoryName,'/',M_.fname,'_ident_moments'])
eval(['print -depsc2 ' IdentifDirectoryName '/' M_.fname '_ident_moments']);
eval(['print -dpdf ' IdentifDirectoryName '/' M_.fname '_ident_moments']);
if options_.nograph, close(gcf); end
figure('Name','Condition Number'),
subplot(221)
hist(log10(idemodel.cond))
title('log10 of Condition number in the model')
subplot(222)
hist(log10(idemoments.cond))
title('log10 of Condition number in the moments')
subplot(223)
hist(log10(idelre.cond))
title('log10 of Condition number in the LRE model')
saveas(gcf,[IdentifDirectoryName,'/',M_.fname,'_ident_COND'])
eval(['print -depsc2 ' IdentifDirectoryName '/' M_.fname '_ident_COND']);
eval(['print -dpdf ' IdentifDirectoryName '/' M_.fname '_ident_COND']);
if options_.nograph, close(gcf); end
ifig=0;
nbox = min(estim_params_.np-1,12);
for j=1:estim_params_.np,
if mod(j,12)==1,
ifig = ifig+1;
figure('name','Partial correlations in the LRE model'),
iplo=0;
end
iplo=iplo+1;
mmm = mean(squeeze(idelre.Pco(:,j,:))');
[sss, immm] = sort(-mmm);
subplot(3,4,iplo),
myboxplot(squeeze(idelre.Pco(immm(2:nbox+1),j,:))'),
set(gca,'ylim',[0 1])
set(gca,'xticklabel','')
for ip=1:nbox, %estim_params_.np,
text(ip,-0.02,deblank(M_.param_names(estim_params_.param_vals(immm(ip+1),1),:)),'rotation',90,'HorizontalAlignment','right','interpreter','none')
end
title(deblank(M_.param_names(estim_params_.param_vals(j,1),:))),
if j==estim_params_.np | mod(j,12)==0
saveas(gcf,[IdentifDirectoryName,'/',M_.fname,'_ident_PCORR_LRE',int2str(ifig)])
eval(['print -depsc2 ' IdentifDirectoryName '/' M_.fname '_ident_PCORR_LRE',int2str(ifig)]);
eval(['print -dpdf ' IdentifDirectoryName '/' M_.fname '_ident_PCORR_LRE',int2str(ifig)]);
if options_.nograph, close(gcf); end
end
end
ifig=0;
nbox = min(nparam-1,12);
for j=1:nparam,
if mod(j,12)==1,
ifig = ifig+1;
figure('name','Partial correlations in the model'),
iplo=0;
end
iplo=iplo+1;
mmm = mean(squeeze(idemodel.Pco(:,j,:))');
[sss, immm] = sort(-mmm);
subplot(3,4,iplo),
myboxplot(squeeze(idemodel.Pco(immm(2:nbox+1),j,:))'),
set(gca,'ylim',[0 1])
set(gca,'xticklabel','')
for ip=1:nbox, %estim_params_.np,
text(ip,-0.02,bayestopt_.name{immm(ip+1)},'rotation',90,'HorizontalAlignment','right','interpreter','none')
end
title(bayestopt_.name{j}),
if j==nparam | mod(j,12)==0
saveas(gcf,[IdentifDirectoryName,'/',M_.fname,'_ident_PCORR_model',int2str(ifig)])
eval(['print -depsc2 ' IdentifDirectoryName '/' M_.fname '_ident_PCORR_model',int2str(ifig)]);
eval(['print -dpdf ' IdentifDirectoryName '/' M_.fname '_ident_PCORR_model',int2str(ifig)]);
if options_.nograph, close(gcf); end
end
end
ifig=0;
nbox = min(nparam-1,12);
for j=1:nparam,
if mod(j,12)==1,
ifig = ifig+1;
figure('name','Partial correlations in the 1st and 2nd moments'),
iplo=0;
end
iplo=iplo+1;
mmm = mean(squeeze(idemoments.Pco(:,j,:))');
[sss, immm] = sort(-mmm);
subplot(3,4,iplo),
myboxplot(squeeze(idemoments.Pco(immm(2:nbox+1),j,:))'),
set(gca,'ylim',[0 1])
set(gca,'xticklabel','')
for ip=1:nbox, %estim_params_.np,
text(ip,-0.02,bayestopt_.name{immm(ip+1)},'rotation',90,'HorizontalAlignment','right','interpreter','none')
end
title(bayestopt_.name{j}),
if j==nparam | mod(j,12)==0
saveas(gcf,[IdentifDirectoryName,'/',M_.fname,'_ident_PCORR_moments',int2str(ifig)])
eval(['print -depsc2 ' IdentifDirectoryName '/' M_.fname '_ident_PCORR_moments',int2str(ifig)]);
eval(['print -dpdf ' IdentifDirectoryName '/' M_.fname '_ident_PCORR_moments',int2str(ifig)]);
if options_.nograph, close(gcf); end
end
end
if exist('OCTAVE_VERSION')
warning('on', 'Octave:divide-by-zero')
else
warning on MATLAB:dividebyzero
end