dynare/tests/solver-test-functions/broydentridiagonal.m

56 lines
1.5 KiB
Matlab

function [fval, fjac] = broydentridiagonal(x)
% Copyright © 2021 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 <https://www.gnu.org/licenses/>.
n = length(x);
if isnumeric(x) && isvector(x) && all(~isnan(x))
fval = zeros(n, 1);
for k=1:n
tmp = (3-2*x(k))*x(k);
tmp1 = 0;
if k~=1
tmp1 = x(k-1);
end
tmp2 = 0;
if k~=n
tmp2 = x(k+1);
end
fval(k) = tmp-tmp1-2*tmp2+1;
end
if nargout>1
fjac = zeros(n);
for k=1:n
fjac(k,k) = 3-4*x(k);
if k~=1
fjac(k,k-1) = -1;
end
if k~=n
fjac(k,k+1) = -2;
end
end
end
elseif isnumeric(x) && isvector(x) && all(isnan(x))
if nargout==1
fval = -ones(n, 1);
else
error('One output is required for initialization mode.')
end
else
error('Wrong input argument.')
end