eoMGGReplacement.h

//-----------------------------------------------------------------------------

#ifndef _eoMGGReplacement_h
#define _eoMGGReplacement_h


//-----------------------------------------------------------------------------
#include <eoPop.h>
#include <eoFunctor.h>
#include <eoMerge.h>
#include <eoReduce.h>
#include <utils/eoHowMany.h>
#include <eoReduceSplit.h>
//-----------------------------------------------------------------------------

template <class EOT>
class eoMGGReplacement : public eoReplacement<EOT>
{
public:
  eoMGGReplacement(eoHowMany _howManyEliminatedParents = eoHowMany(2, false),
                   unsigned _tSize=2) :
    // split truncates the parents and returns eliminated parents
    split(_howManyEliminatedParents, true), 
    tSize(_tSize)
  {
    if (tSize < 2)
      { 
        std::cout << "Warning, Size for eoDetTournamentTruncateSplit adjusted to 2\n";
        tSize = 2;
      }
  }
    
    void operator()(eoPop<EOT> & _parents, eoPop<EOT> & _offspring)
    {
      eoPop<EOT> temp;
      split(_parents, temp);
      unsigned toKeep = temp.size(); // how many to keep from merged populations
      // minimal check
      if (toKeep < 2)
        throw std::runtime_error("Not enough parents killed in eoMGGReplacement");

      // select best offspring
      typename eoPop<EOT>::iterator it = _offspring.it_best_element();
      // add to parents
      _parents.push_back(*it);
      // remove from offspring
      _offspring.erase(it);

      // merge temp into offspring
      plus(temp, _offspring);
      
      // repeatedly add selected offspring to parents
      for (unsigned i=0; i<toKeep-1; i++)
        {
          // select
          it = deterministic_tournament(_offspring.begin(), _offspring.end(), tSize);
          // add to parents
          _parents.push_back(*it);
          // remove from offspring
          _offspring.erase(it);
        }
    }

private:
  eoLinearTruncateSplit<EOT> split; // few parents to truncate -> linear 
  eoPlus<EOT> plus;
  unsigned int tSize;
};

#endif

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