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

60 lines
1.6 KiB
Matlab

function [fval, fjac] = helicalvalley(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/>.
C7 = 0.25;
C8 = 0.5;
TPI = 8*atan(1);
if nargin==1
fval = zeros(3, 1);
tmp1 = C7*sign(x(2));
if x(1)>0
tmp1 = atan(x(2)/x(1))/TPI;
end
if x(1)<0
tmp1 = atan(x(2)/x(1))/TPI+C8;
end
tmp2 = sqrt(x(1)*x(1)+x(2)*x(2));
fval(1) = 10*(x(3)-10*tmp1);
fval(2) = 10*(tmp2-1);
fval(3) = x(3);
if nargout>1
fjac = zeros(3);
tmp = x(1)*x(1)+x(2)*x(2);
tmp1 = TPI*tmp;
tmp2 = sqrt(tmp);
fjac(1,1) = 100*x(2)/tmp1;
fjac(1,2) = -100*x(1)/tmp1;
fjac(1,3) = 10;
fjac(2,1) = 10*x(1)/tmp2;
fjac(2,2) = 10*x(2)/tmp2;
fjac(2,3) = 0;
fjac(3,1) = 0;
fjac(3,2) = 0;
fjac(3,3) = 1;
end
elseif ~nargin
if nargout==1
fval = [-1; 0; 0];
else
error('One output is required for initialization mode.')
end
else
error('Wrong number of input arguments.')
end