/usr/share/dynare/matlab/bfgsi1.m is in dynare-common 4.4.1-1build1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 | function H = bfgsi1(H0,dg,dx)
% H = bfgsi1(H0,dg,dx)
% dg is previous change in gradient; dx is previous change in x;
% 6/8/93 version that updates inverse hessian instead of hessian
% itself.
% Original file downloaded from:
% http://sims.princeton.edu/yftp/optimize/mfiles/bfgsi.m
% Copyright (C) 1993-2009 Christopher Sims
%
% 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/>.
if size(dg,2)>1
dg=dg';
end
if size(dx,2)>1
dx=dx';
end
Hdg = H0*dg;
dgdx = dg'*dx;
if (abs(dgdx) >1e-12)
H = H0 + (1+(dg'*Hdg)/dgdx)*(dx*dx')/dgdx - (dx*Hdg'+Hdg*dx')/dgdx;
else
disp('bfgs update failed.')
disp(['|dg| = ' num2str(sqrt(dg'*dg)) '|dx| = ' num2str(sqrt(dx'*dx))]);
disp(['dg''*dx = ' num2str(dgdx)])
disp(['|H*dg| = ' num2str(Hdg'*Hdg)])
H=H0;
end
save H.dat H
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