% Chen Bird's function L. LAURENT -- 04/11/2016 -- luc.laurent@lecnam.net
0001 %% Chen Bird's function 0002 %L. LAURENT -- 04/11/2016 -- luc.laurent@lecnam.net 0003 0004 % sources available here: 0005 % https://bitbucket.org/luclaurent/optigtest/ 0006 % https://github.com/luclaurent/optigtest/ 0007 0008 % optiGTest - set of testing functions A toolbox to easy manipulate functions. 0009 % Copyright (C) 2017 Luc LAURENT <luc.laurent@lecnam.net> 0010 % 0011 % This program is free software: you can redistribute it and/or modify 0012 % it under the terms of the GNU General Public License as published by 0013 % the Free Software Foundation, either version 3 of the License, or 0014 % (at your option) any later version. 0015 % 0016 % This program is distributed in the hope that it will be useful, 0017 % but WITHOUT ANY WARRANTY; without even the implied warranty of 0018 % MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 0019 % GNU General Public License for more details. 0020 % 0021 % You should have received a copy of the GNU General Public License 0022 % along with this program. If not, see <http://www.gnu.org/licenses/>. 0023 0024 % 0025 %2 global minima 0026 %f(x1,x2)=-2000 for (x1,x2)={(0.5,0.5),(-0.5,-0.5)} 0027 % 0028 %Design space: -500<x1,x2<500 0029 0030 0031 0032 0033 function [p,dp]=funChenBird(xx) 0034 0035 %constants 0036 a=1e-3; 0037 b=1; 0038 c=0.5; 0039 0040 %variables 0041 xxx=xx(:,:,1); 0042 yyy=xx(:,:,2); 0043 0044 %evaluations and derivatives 0045 pa=xxx.^2+yyy.^2-b; 0046 da=a^2+pa.^2; 0047 pb=xxx.^2+yyy.^2-c; 0048 db=a^2+pb.^2; 0049 pc=xxx-yyy; 0050 dc=a^2+pc.^2; 0051 p=-a./da-a./db-a./dc; 0052 0053 if nargout==2 0054 dp(:,:,1)=4*a*xxx.*pa./da.^2 ... 0055 +4*a*xxx.*pb./db.^2 ... 0056 +2*a.*pc./dc.^2; 0057 dp(:,:,2)=4*a*yyy.*pa./da.^2 ... 0058 +4*a*yyy.*pb./db.^2 ... 0059 -2*a.*pc./dc.^2; 0060 end 0061 end