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# eoSBXcross.h

    00001 // -*- mode: c++; c-indent-level: 4; c++-member-init-indent: 8; comment-column: 35; -*-
    00002
    00003 //-----------------------------------------------------------------------------
    00004 // eoSBXcross.h
    00005 // (c) Maarten Keijzer 2000 - Marc Schoenauer 2001
    00006 /*
    00007     This library is free software; you can redistribute it and/or
    00008     modify it under the terms of the GNU Lesser General Public
    00009     License as published by the Free Software Foundation; either
    00010     version 2 of the License, or (at your option) any later version.
    00011
    00012     This library is distributed in the hope that it will be useful,
    00013     but WITHOUT ANY WARRANTY; without even the implied warranty of
    00014     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
    00015     Lesser General Public License for more details.
    00016
    00017     You should have received a copy of the GNU Lesser General Public
    00018     License along with this library; if not, write to the Free Software
    00019     Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
    00020
    00021     Contact: Marc.Schoenauer@polytechnique.fr
    00022              mak@dhi.dk
    00023  */
    00024 //-----------------------------------------------------------------------------
    00025
    00026 #include <algorithm>    // swap_ranges
    00027 #include <utils/eoParser.h>
    00028 #include <utils/eoRNG.h>
    00029 #include <es/eoReal.h>
    00030 #include <utils/eoRealBounds.h>
    00031 #include <utils/eoRealVectorBounds.h>
    00032
    00033
    00034
    00035 template<class EOT> class eoSBXCrossover: public eoQuadOp<EOT>
    00036 {
    00037  public:
    00038   /****
    00039    * (Default) Constructor.
    00040    * The bounds are initialized with the global object that says: no bounds.
    00041    *
    00042    *
    00043    */
    00044     eoSBXCrossover(const double& _eta = 1.0) :
    00045     bounds(eoDummyVectorNoBounds), eta(_eta), range(1) {}
    00046
    00047
    00049
    00061      eoSBXCrossover(eoRealVectorBounds & _bounds,
    00062                      const double& _eta = 1.0) :
    00063      bounds(_bounds), eta(_eta), range(1) {}
    00064
    00066
    00068
    00075      eoSBXCrossover(eoParser & _parser) :
    00076     // First, decide whether the objective variables are bounded
    00077     // Warning, must be the same keywords than other possible objectBounds elsewhere
    00078        bounds (_parser.getORcreateParam(eoDummyVectorNoBounds, "objectBounds", "Bounds for variables", 'B', "Variation Operators").value()) ,
    00079     // then get eta value
    00080        eta (_parser.getORcreateParam(1.0, "eta", "SBX eta parameter", '\0', "Variation Operators").value()) ,
    00081        range(1) {}
    00082
    00083
    00085   virtual std::string className() const { return "eoSBXCrossover"; }
    00086
    00087   /*****************************************
    00088    * SBX crossover - modifies both parents *
    00089    * @param _eo1 The first parent          *
    00090    * @param _eo2 The first parent          *
    00091    *****************************************/
    00092   bool operator()(EOT& _eo1, EOT& _eo2)
    00093     {
    00094       unsigned i;
    00095       double r1, r2, beta;
    00096
    00097         for (i=0; i<_eo1.size(); i++)
    00098           {
    00099       double u = rng.uniform(range) ;
    00100
    00101       if ( u <= 0.5 )
    00102         beta = exp( (1/(eta+1))*log(2*u));
    00103       else
    00104         beta = exp((1/(eta+1))*log(1/(2*(1-u))));
    00105
    00106
    00107
    00108               r1=_eo1[i];
    00109               r2=_eo2[i];
    00110               _eo1[i] =0.5*((1+beta)*r1+(1-beta)*r2);
    00111               _eo2[i] =0.5*((1-beta)*r1+(1+beta)*r2);
    00112
    00113
    00114               if(!(bounds.isInBounds(i,_eo1[i])))
    00115                 bounds.foldsInBounds(i,_eo1[i]);
    00116               if(!(bounds.isInBounds(i,_eo2[i])))
    00117                 bounds.foldsInBounds(i,_eo2[i]);
    00118
    00119
    00120
    00121            }
    00122         return true;
    00123         }
    00124
    00125
    00126
    00127 protected:
    00128   eoRealVectorBounds & bounds;
    00129   double eta;
    00130   double range;                    // == 1
    00131 };
    00132
    00133