funSchwefel26

PURPOSE ^

% Schwefel 26 function

SYNOPSIS ^

function [p,dp]=funSchwefel26(xx)

DESCRIPTION ^

% Schwefel 26 function
L. LAURENT -- 26/01/2011 -- luc.laurent@lecnam.net
modif on the 16/09/2011 -- change to n variables

 sources available here:
 https://bitbucket.org/luclaurent/optigtest/
 https://github.com/luclaurent/optigtest/

CROSS-REFERENCE INFORMATION ^

This function calls: This function is called by:

SOURCE CODE ^

0001 %% Schwefel 26 function
0002 %L. LAURENT -- 26/01/2011 -- luc.laurent@lecnam.net
0003 %modif on the 16/09/2011 -- change to n variables
0004 %
0005 % sources available here:
0006 % https://bitbucket.org/luclaurent/optigtest/
0007 % https://github.com/luclaurent/optigtest/
0008 
0009 % optiGTest - set of testing functions    A toolbox to easy manipulate functions.
0010 % Copyright (C) 2017  Luc LAURENT <luc.laurent@lecnam.net>
0011 %
0012 % This program is free software: you can redistribute it and/or modify
0013 % it under the terms of the GNU General Public License as published by
0014 % the Free Software Foundation, either version 3 of the License, or
0015 % (at your option) any later version.
0016 %
0017 % This program is distributed in the hope that it will be useful,
0018 % but WITHOUT ANY WARRANTY; without even the implied warranty of
0019 % MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
0020 % GNU General Public License for more details.
0021 %
0022 % You should have received a copy of the GNU General Public License
0023 % along with this program.  If not, see <http://www.gnu.org/licenses/>.
0024 
0025 %numerous local minima
0026 %1 global minimum : x=(420.968746,420.968746,...,420.968746) >> f(x)=0
0027 %
0028 %Design space: -500<xi<500
0029 
0030 function [p,dp]=funSchwefel26(xx)
0031 
0032 %constants
0033 a=418.9829;
0034 nbvar=size(xx,3);
0035 
0036 %evaluation and derivatives
0037 pa=abs(xx);
0038 sqa=sqrt(pa);
0039 ssqa=sin(sqa);
0040 pb=xx.*ssqa;
0041 %
0042 p=a*nbvar-sum(pb,3);
0043 %
0044 if nargout==2
0045     %
0046     csqa=cos(sqa);
0047     dp=-ssqa-xx.*sign(xx).*csqa./(2*sqa);
0048     iXZ=(abs(xx(:))<eps);
0049     dp(iXZ)=0;
0050 end
0051 
0052 end

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