paradiseo/moeo/src/metric/moeoEntropyMetric.h
2012-08-30 11:30:11 +02:00

223 lines
7.1 KiB
C++

/*
* <moeoEntropyMetric.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 MOEOENTROPYMETRIC_H_
#define MOEOENTROPYMETRIC_H_
#include <vector>
#include <comparator/moeoParetoObjectiveVectorComparator.h>
#include <metric/moeoMetric.h>
/**
* The entropy gives an idea of the diversity of a Pareto set relatively to another
* (Basseur, Seynhaeve, Talbi: 'Design of Multi-objective Evolutionary Algorithms: Application to the Flow-shop Scheduling Problem', in Proc. of the 2002 Congress on Evolutionary Computation, IEEE Press, pp. 1155-1156)
*/
template < class ObjectiveVector >
class moeoEntropyMetric : public moeoVectorVsVectorBinaryMetric < ObjectiveVector, double >
{
public:
/**
* Returns the entropy of the Pareto set '_set1' relatively to the Pareto set '_set2'
* @param _set1 the first Pareto set
* @param _set2 the second Pareto set
*/
double operator()(const std::vector < ObjectiveVector > & _set1, const std::vector < ObjectiveVector > & _set2)
{
// normalization
std::vector< ObjectiveVector > set1 = _set1;
std::vector< ObjectiveVector > set2= _set2;
removeDominated (set1);
removeDominated (set2);
prenormalize (set1);
normalize (set1);
normalize (set2);
// making of PO*
std::vector< ObjectiveVector > star; // rotf :-)
computeUnion (set1, set2, star);
removeDominated (star);
// making of PO1 U PO*
std::vector< ObjectiveVector > union_set1_star; // rotf again ...
computeUnion (set1, star, union_set1_star);
unsigned int C = union_set1_star.size();
float omega=0;
float entropy=0;
for (unsigned int i=0 ; i<C ; i++)
{
unsigned int N_i = howManyInNicheOf (union_set1_star, union_set1_star[i], star.size());
unsigned int n_i = howManyInNicheOf (set1, union_set1_star[i], star.size());
if (n_i > 0)
{
omega += 1.0 / N_i;
entropy += (float) n_i / (N_i * C) * log (((float) n_i / C) / log (2.0));
}
}
entropy /= - log (omega);
entropy *= log (2.0);
return entropy;
}
private:
/** vector of min values */
std::vector<double> vect_min_val;
/** vector of max values */
std::vector<double> vect_max_val;
/** Functor to compare two objective vectors according to Pareto dominance relation */
moeoParetoObjectiveVectorComparator < ObjectiveVector > paretoComparator;
/**
* Removes the dominated individuals contained in _f
* @param _f a Pareto set
*/
void removeDominated(std::vector < ObjectiveVector > & _f)
{
for (unsigned int i=0 ; i<_f.size(); i++)
{
bool dom = false;
for (unsigned int j=0; j<_f.size(); j++)
if (i != j && paretoComparator(_f[i],_f[j]))
{
dom = true;
break;
}
if (dom)
{
_f[i] = _f.back();
_f.pop_back();
i--;
}
}
}
/**
* Prenormalization
* @param _f a Pareto set
*/
void prenormalize (const std::vector< ObjectiveVector > & _f)
{
vect_min_val.clear();
vect_max_val.clear();
for (unsigned int i=0 ; i<ObjectiveVector::nObjectives(); i++)
{
float min_val = _f.front()[i], max_val = min_val;
for (unsigned int j=1 ; j<_f.size(); j++)
{
if (_f[j][i] < min_val)
min_val = _f[j][i];
if (_f[j][i]>max_val)
max_val = _f[j][i];
}
vect_min_val.push_back(min_val);
vect_max_val.push_back (max_val);
}
}
/**
* Normalization
* @param _f a Pareto set
*/
void normalize (std::vector< ObjectiveVector > & _f)
{
for (unsigned int i=0 ; i<ObjectiveVector::nObjectives(); i++)
for (unsigned int j=0; j<_f.size(); j++)
_f[j][i] = (_f[j][i] - vect_min_val[i]) / (vect_max_val[i] - vect_min_val[i]);
}
/**
* Computation of the union of _f1 and _f2 in _f
* @param _f1 the first Pareto set
* @param _f2 the second Pareto set
* @param _f the final Pareto set
*/
void computeUnion(const std::vector< ObjectiveVector > & _f1, const std::vector< ObjectiveVector > & _f2, std::vector< ObjectiveVector > & _f)
{
_f = _f1 ;
for (unsigned int i=0; i<_f2.size(); i++)
{
bool b = false;
for (unsigned int j=0; j<_f1.size(); j ++)
if (_f1[j] == _f2[i])
{
b = true;
break;
}
if (! b)
_f.push_back(_f2[i]);
}
}
/**
* How many in niche
*/
unsigned int howManyInNicheOf (const std::vector< ObjectiveVector > & _f, const ObjectiveVector & _s, unsigned int _size)
{
unsigned int n=0;
for (unsigned int i=0 ; i<_f.size(); i++)
{
if (euclidianDistance(_f[i], _s) < (_s.size() / (double) _size))
n++;
}
return n;
}
/**
* Euclidian distance
*/
double euclidianDistance (const ObjectiveVector & _set1, const ObjectiveVector & _to, unsigned int _deg = 2)
{
double dist=0;
for (unsigned int i=0; i<_set1.size(); i++)
dist += pow(fabs(_set1[i] - _to[i]), (int)_deg);
return pow(dist, 1.0 / _deg);
}
};
#endif /*MOEOENTROPYMETRIC_H_*/