# eoOneToOneBreeder.h

    00001 // -*- mode: c++; c-indent-level: 4; c++-member-init-indent: 8; comment-column: 35; -*-
    00002
    00003 //-----------------------------------------------------------------------------
    00004 // eoOneToOneBreeder.h
    00005 // (c) Maarten Keijzer and 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: mkeijzer@dhi.dk
    00022              Marc.Schoenauer@polytechnique.fr
    00023  */
    00024 //-----------------------------------------------------------------------------
    00025
    00026 #ifndef eoOneToOneBreeder_h
    00027 #define eoOneToOneBreeder_h
    00028
    00029 //-----------------------------------------------------------------------------
    00030
    00031 #include <eoOp.h>
    00032 #include <eoGenOp.h>
    00033 #include <eoPopulator.h>
    00034 #include <eoSelectOne.h>
    00035 #include <eoSequentialSelect.h>
    00036 #include <eoBreed.h>
    00037 #include <eoEvalFunc.h>
    00038 #include <eoPopulator.h>
    00039 #include <utils/eoHowMany.h>
    00040
    00041 /*****************************************************************************
    00042  * eoOneToOneBreeder: transforms a population using
    00043  *   - an operator that MODIFIES only one parent from the populator
    00044  *     (though it can use any number aside) and thus generates ONE offspring)
    00045  *   - a local replacement between the parent and its offspring
    00046  *
    00047  * Typically, Differential Evolution (Storn and Price 94) and Deb et al's
    00048  *   G3 can be built on this
    00049  ****************************************************************************
    00050  */
    00051 template<class EOT>
    00052 class eoOneToOneBreeder: public eoBreed<EOT>
    00053 {
    00054  public:
    00062   eoOneToOneBreeder(
    00063           eoGenOp<EOT>& _op,
    00064           eoEvalFunc<EOT> & _eval,
    00065           double _pReplace = 1.0,
    00066           eoHowMany _howMany = eoHowMany(1.0) ) :
    00067       op(_op), eval(_eval), select( false ),
    00068       pReplace(_pReplace), howMany(_howMany) {}
    00069
    00070
    00078   void operator()(const eoPop<EOT>& _parents, eoPop<EOT>& _offspring)
    00079     {
    00080       unsigned target = howMany(_parents.size());
    00081
    00082       _offspring.clear();
    00083       eoSelectivePopulator<EOT> popit(_parents, _offspring, select);
    00084
    00085       for (unsigned iParent=0; iParent<target; iParent++)
    00086         {
    00087           unsigned pos = popit.tellp(); // remember current position
    00088           EOT theParent = *popit;  // remember the parent itself
    00089
    00090           // now apply operator - will modify the parent
    00091           op(popit);
    00092
    00093           // replacement
    00094           EOT & leOffspring = *popit;
    00095
    00096           // check: only one offspring?
    00097           unsigned posEnd = popit.tellp();
    00098           if (posEnd != pos)
    00099             throw std::runtime_error("Operator can only generate a SINGLE offspring in eoOneToOneBreeder");
    00100
    00101           // do the tournament between parent and offspring
    00102           eval(leOffspring);  // first need to evaluate the offspring
    00103           if (theParent > leOffspring) // old parent better than offspring
    00104             if (rng.uniform() < pReplace) // if probability
    00105               leOffspring = theParent; // replace
    00106           // finally, go to next guy to handle
    00107           ++popit;
    00108         }
    00109     }
    00110
    00112   virtual std::string className() const { return "eoOneToOneBreeder"; }
    00113
    00114  private:
    00115   eoGenOp<EOT>& op;
    00116   eoEvalFunc<EOT> & eval;
    00117   eoSequentialSelect<EOT> select;
    00118   double pReplace;
    00119   eoHowMany howMany;
    00120 };
    00121
    00122 #endif
    00123