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

60 lines
1.6 KiB
Matlab

function [fval, fjac] = broydenbanded(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);
ml = 5;
mu = 1;
for k=1:n
k1 = max(1, k-ml);
k2 = min(k+mu, n);
tmp = 0;
for j=k1:k2
if j~=k
tmp = tmp + x(j)*(1+x(j));
end
end
fval(k) = x(k)*(2+5*x(k)*x(k))+1-tmp;
end
if nargout>1
fjac = zeros(n);
ml = 5;
mu = 1;
for k=1:n
k1 = max(1,k-ml);
k2 = min(k+mu,n);
for j=k1:k2
if j~=k
fjac(k,j) = -(1+2*x(j));
end
end
fjac(k,k) = 2+15*x(k)*x(k);
end
end
elseif isnumeric(x) && isvector(x) && all(isnan(x))
if nargout==1
fval = broydentridiagonal(nan(n,1));
else
error('One output is required for initialization mode.')
end
else
error('Wrong input argument.')
end