freESCommaSelection.txx

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/*=========================================================================

  Program:   F.R.E.E. - flexible registration evaluation engine
  Version:   v.1.0.0
  Date:      $Date: 2006/09/01 12:00:00 $
  Module:    $RCSfile: freESCommaSelection.txx,v $
  Language:  C++



  Copyright (c) 2007 Ralf o Floca (Department of Medical Informatics,
  Institute for Medical Biometry and Informatics, University of Heidelberg,
  Germany). All rights reserved.
  See FREECopyright.txt or http://www.mi.med.uni-hd.de/free/copyright.htm
  for details.

     This software is distributed WITHOUT ANY WARRANTY; without even 
     the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR 
     PURPOSE.  See the above copyright notices for more information.

=========================================================================*/
#ifndef _freESCommaSelection_txx
#define _freESCommaSelection_txx

#include "freESCommaSelection.h"

namespace FREE
{
  namespace ES
  {

    template <class TIndividual>
    CommaSelection<TIndividual>
      ::CommaSelection()
    {
      m_MaxGenerationAge = 0;
      this->m_PlusSelection = PrivatPlusSelectionType::New();
    }

    template <class TIndividual>
    typename CommaSelection<TIndividual>::PopulationPointer
    CommaSelection<TIndividual>
    ::Select(PopulationType* pPopulation, PopulationSizeType newSize) const
    {
      if (!pPopulation) throwExceptionMacro("Error. Passed population is NULL.");
      if (pPopulation->Size()<newSize) throwExceptionMacro("Error. Passed population is already smaller the prefered size, nothing to select. Population size: "<<pPopulation->Size()<<"; new size: "<<newSize);

      PopulationPointer removedPopulation = PopulationType::New();

      //search for individual that should be removed because of their age
      if (pPopulation->Size()>0)
      {
        for (long index = pPopulation->Size()-1; index > -1 ; index--)
        { 
          // the ID of new children of the current generation is 1+ the population generation id,
          // so this childs will have an age of 0.
          unsigned long age = (pPopulation->GetGenerationID()+1)-((*pPopulation)[index])->GetGenerationID();
          if ( age > m_MaxGenerationAge)
          {
            //remove old individual and add it to the population of removed individuals
            removedPopulation->push_back((*pPopulation)[index]);
            pPopulation->erase(pPopulation->begin()+index);
          }
        }
      }

      if (pPopulation->Size()<newSize) throwExceptionMacro("Error. Passed population has not enough new children. After removing old individuals population is too small. Ensure that the number of new children per generation is greater or equal the number of parents, when using a comma selection.");

      //now remove the worst individuals (similar to plus selection)
      PopulationPointer removedPop2 = this->m_PlusSelection->Select(pPopulation, newSize);

      //join both removed populations
      for (unsigned long index = 0; index < removedPop2->Size(); index++)
      { 
        removedPopulation->push_back(removedPop2->ElementAt(index));
      }

      return removedPopulation;
    };

  } // end of namespace ES
} // end of namespace FREE

#endif

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