paradiseo/moeo/src/diversity/moeoCrowdingDiversityAssignment.h
2024-08-23 18:00:31 +02:00

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4.9 KiB
C++

/*
* <moeoCrowdingDiversityAssignment.h>
* Copyright (C) DOLPHIN Project-Team, INRIA Futurs, 2006-2007
* (C) OPAC Team, LIFL, 2002-2007
*
* Arnaud Liefooghe
*
* This software is governed by the CeCILL license under French law and
* abiding by the rules of distribution of free software. You can use,
* modify and/ or redistribute the software under the terms of the CeCILL
* license as circulated by CEA, CNRS and INRIA at the following URL
* "http://www.cecill.info".
*
* As a counterpart to the access to the source code and rights to copy,
* modify and redistribute granted by the license, users are provided only
* with a limited warranty and the software's author, the holder of the
* economic rights, and the successive licensors have only limited liability.
*
* In this respect, the user's attention is drawn to the risks associated
* with loading, using, modifying and/or developing or reproducing the
* software by the user in light of its specific status of free software,
* that may mean that it is complicated to manipulate, and that also
* therefore means that it is reserved for developers and experienced
* professionals having in-depth computer knowledge. Users are therefore
* encouraged to load and test the software's suitability as regards their
* requirements in conditions enabling the security of their systems and/or
* data to be ensured and, more generally, to use and operate it in the
* same conditions as regards security.
* The fact that you are presently reading this means that you have had
* knowledge of the CeCILL license and that you accept its terms.
*
* ParadisEO WebSite : http://paradiseo.gforge.inria.fr
* Contact: paradiseo-help@lists.gforge.inria.fr
*
*/
//-----------------------------------------------------------------------------
#ifndef MOEOCROWDINGDIVERSITYASSIGNMENT_H_
#define MOEOCROWDINGDIVERSITYASSIGNMENT_H_
#include <eoPop.h>
#include <comparator/moeoOneObjectiveComparator.h>
#include <diversity/moeoDiversityAssignment.h>
/**
* Diversity assignment sheme based on crowding proposed in:
* K. Deb, A. Pratap, S. Agarwal, T. Meyarivan, "A Fast and Elitist Multi-Objective Genetic Algorithm: NSGA-II", IEEE Transactions on Evolutionary Computation, vol. 6, no. 2 (2002).
*/
template < class MOEOT >
class moeoCrowdingDiversityAssignment : public moeoDiversityAssignment < MOEOT >
{
public:
/** the objective vector type of the solutions */
typedef typename MOEOT::ObjectiveVector ObjectiveVector;
/**
* Returns a big value (regarded as infinite)
*/
double inf() const
{
return std::numeric_limits<double>::max();
}
/**
* Returns a very small value that can be used to avoid extreme cases (where the min bound == the max bound)
*/
double tiny() const
{
return 1e-6;
}
/**
* Computes diversity values for every solution contained in the population _pop
* @param _pop the population
*/
void operator()(eoPop < MOEOT > & _pop)
{
if (_pop.size() <= 2)
{
for (unsigned int i=0; i<_pop.size(); i++)
{
_pop[i].diversity(inf());
}
}
else
{
setDistances(_pop);
}
}
/**
* @warning NOT IMPLEMENTED, DO NOTHING !
* Updates the diversity values of the whole population _pop by taking the deletion of the objective vector _objVec into account.
* @param _pop the population
* @param _objVec the objective vector
* @warning NOT IMPLEMENTED, DO NOTHING !
*/
void updateByDeleting(eoPop < MOEOT > & /*_pop*/, ObjectiveVector & /*_objVec*/)
{
std::cout << "WARNING : updateByDeleting not implemented in moeoCrowdingDiversityAssignment" << std::endl;
}
protected:
/**
* Sets the distance values
* @param _pop the population
*/
virtual void setDistances (eoPop < MOEOT > & _pop)
{
double min, max, distance;
unsigned int nObjectives = MOEOT::ObjectiveVector::nObjectives();
// set diversity to 0
for (unsigned int i=0; i<_pop.size(); i++)
{
_pop[i].diversity(0.0);
}
// for each objective
for (unsigned int obj=0; obj<nObjectives; obj++)
{
// comparator
moeoOneObjectiveComparator < MOEOT > objComp(obj);
// sort
std::sort(_pop.begin(), _pop.end(), objComp);
// min & max
min = _pop[0].objectiveVector()[obj];
max = _pop[_pop.size()-1].objectiveVector()[obj];
// set the diversity value to infiny for min and max
_pop[0].diversity(inf());
_pop[_pop.size()-1].diversity(inf());
for (unsigned int i=1; i<_pop.size()-1; i++)
{
distance = (_pop[i+1].objectiveVector()[obj] - _pop[i-1].objectiveVector()[obj]) / (max-min);
_pop[i].diversity(_pop[i].diversity() + distance);
}
}
}
};
#endif /*MOEOCROWDINGDIVERSITYASSIGNMENT_H_*/