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bug corrected

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git-svn-id: svn://scm.gforge.inria.fr/svnroot/paradiseo@294 331e1502-861f-0410-8da2-ba01fb791d7f
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liefooga 2007-05-14 13:30:11 +00:00
commit 34a339e96a
1 changed files with 73 additions and 17 deletions
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90
branches/paradiseo-moeo-1.0/src/moeoCrowdingDistanceDiversityAssignment.h
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@ -40,6 +40,15 @@ public:
}
/**
* 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
@ -81,34 +90,81 @@ private:
*/
void setDistances (eoPop < MOEOT > & _pop)
{
unsigned a,b;
double min, max, distance;
unsigned nObjectives = MOEOT::ObjectiveVector::nObjectives();
// set diversity to 0
// set diversity to 0 for every individual
for (unsigned i=0; i<_pop.size(); i++)
{
_pop[i].diversity(0);
_pop[i].diversity(0.0);
}
// for each objective
for (unsigned obj=0; obj<nObjectives; obj++)
// sort the whole pop according to fitness values
moeoFitnessThenDiversityComparator < MOEOT > fitnessComparator;
std::sort(_pop.begin(), _pop.end(), fitnessComparator);
// compute the crowding distance values for every individual "front" by "front" (front : from a to b)
a = 0; // the front starts at a
while (a < _pop.size())
{
// comparator
moeoOneObjectiveComparator < MOEOT > comp(obj);
// sort
std::sort(_pop.begin(), _pop.end(), comp);
// 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 i=1; i<_pop.size()-1; i++)
b = lastIndex(_pop,a); // the front ends at b
// if there is 2 or less individuals in the front...
if ((b-a) < 2)
{
distance = (_pop[i+1].objectiveVector()[obj] - _pop[i-1].objectiveVector()[obj]) / (max-min);
_pop[i].diversity(_pop[i].diversity() + distance);
for (unsigned i=a; i<=b; i++)
{
_pop[i].diversity(inf());
}
}
// else...
else
{
// for each objective
for (unsigned obj=0; obj<nObjectives; obj++)
{
// sort in the descending order using the values of the objective 'obj'
moeoOneObjectiveComparator < MOEOT > objComp(obj);
std::sort(_pop.begin()+a, _pop.begin()+b+1, objComp);
// min & max
min = _pop[b].objectiveVector()[obj];
max = _pop[a].objectiveVector()[obj];
// avoid extreme case
if (min == max)
{
min -= tiny();
max += tiny();
}
// set the diversity value to infiny for min and max
_pop[a].diversity(inf());
_pop[b].diversity(inf());
// set the diversity values for the other individuals
for (unsigned i=a+1; i<b; i++)
{
distance = (_pop[i-1].objectiveVector()[obj] - _pop[i+1].objectiveVector()[obj]) / (max-min);
_pop[i].diversity(_pop[i].diversity() + distance);
}
}
}
// go to the next front
a = b+1;
}
}
/**
* Returns the index of the last individual having the same fitness value than _pop[_start]
* @param _pop the population
* @param _start the index to start from
*/
unsigned lastIndex (eoPop < MOEOT > & _pop, unsigned _start)
{
unsigned i=_start;
while ( (i<_pop.size()-1) && (_pop[i].fitness()==_pop[i+1].fitness()) )
{
i++;
}
return i;
}
};
#endif /*MOEOCROWDINGDISTANCEDIVERSITYASSIGNMENT_H_*/