paradiseo/eo/src/eoReduceMergeReduce.h

143 lines
4.8 KiB
C++

/** -*- mode: c++; c-indent-level: 4; c++-member-init-indent: 8; comment-column: 35; -*-
-----------------------------------------------------------------------------
eoReduceMergeReduce.h
(c) Maarten Keijzer, Marc Schoenauer, 2002
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2 of the License, or (at your option) any later version.
This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
Contact: Marc.Schoenauer@inria.fr
mkeijzer@dhi.dk
*/
//-----------------------------------------------------------------------------
#ifndef _eoReduceMergeReduce_h
#define _eoReduceMergeReduce_h
//-----------------------------------------------------------------------------
#include <eoPop.h>
#include <eoFunctor.h>
#include <eoMerge.h>
#include <eoReduce.h>
#include <utils/eoHowMany.h>
//-----------------------------------------------------------------------------
/**
eoReduceMergeReduce is an eoReplacement:
- saves possible elite parents
- reduces rest of parents
- reduces offspring
- merges reduced populations
- reduces resulting merged pop if necessary
*/
template <class EOT>
class eoReduceMergeReduce : public eoReplacement<EOT>
{
public:
eoReduceMergeReduce(eoHowMany _howManyElite,
bool _strongElitism,
eoHowMany _howManyReducedParents,
eoReduce<EOT> & _reduceParents,
eoHowMany _howManyReducedOffspring,
eoReduce<EOT> & _reduceOffspring,
eoReduce<EOT> & _reduceFinal) :
howManyElite(_howManyElite),
strongElitism(_strongElitism),
howManyReducedParents(_howManyReducedParents),
howManyReducedOffspring (_howManyReducedOffspring),
reduceParents(_reduceParents),
reduceOffspring(_reduceOffspring),
reduceFinal(_reduceFinal)
{}
void operator()(eoPop<EOT> & _parents, eoPop<EOT> & _offspring)
{
eoPop<EOT> temp;
unsigned int finalPopSize = _parents.size();
unsigned int offSize = _offspring.size();
unsigned int elite = howManyElite(finalPopSize);
if (elite) // some parents MUST be saved somewhere
{
temp.resize(elite);
_parents.nth_element(elite);
std::copy(_parents.begin(), _parents.begin()+elite, temp.begin());
_parents.erase(_parents.begin(), _parents.begin()+elite);
}
// the reduce steps. First the parents
unsigned reducedParentSize = howManyReducedParents(_parents.size());
if (!reducedParentSize)
_parents.clear();
else if (reducedParentSize != _parents.size())
reduceParents(_parents, reducedParentSize);
// then the offspring
unsigned reducedOffspringSize = howManyReducedOffspring(offSize);
if (!reducedOffspringSize)
throw std::runtime_error("No offspring left after reduction!");
if (reducedOffspringSize != offSize) // need reduction
reduceOffspring(_offspring, reducedOffspringSize);
// now merge reduced populations
_parents.resize(reducedParentSize + _offspring.size());
std::copy(_offspring.begin(), _offspring.end(),
_parents.begin()+reducedParentSize);
// reduce the resulting population
// size depstd::ends on elitism
if (elite && strongElitism)
{
if (_parents.size() != finalPopSize-elite)
reduceFinal(_parents, finalPopSize-elite);
// and put back the elite
unsigned oldPSize = _parents.size();
_parents.resize(_parents.size()+elite);
std::copy(temp.begin(), temp.end(), _parents.begin()+oldPSize);
}
else
{ // only reduce final pop to right size
if (_parents.size() != finalPopSize)
reduceFinal(_parents, finalPopSize);
if (elite) // then treat weak elitism
{
unsigned toSave = 0;
_parents.sort();
EOT & eoLimit = _parents[elite-1];
unsigned index=0;
while ( (temp[index++] > eoLimit) && (index < temp.size()) )
toSave++;
if (toSave)
for (unsigned i=0; i<toSave; i++)
_parents[finalPopSize-1-i] = temp[i];
}
}
}
private:
eoHowMany howManyElite; // if 0, no elitism at all
bool strongElitism; // if false -> weak estd::listism
eoHowMany howManyReducedParents; // if 0, no parent in final replacement
eoHowMany howManyReducedOffspring; // if 0, std::runtime_error
// the reducers
eoReduce<EOT> & reduceParents;
eoReduce<EOT> & reduceOffspring;
eoReduce<EOT> & reduceFinal;
};
#endif