115 lines
3.6 KiB
C++
115 lines
3.6 KiB
C++
// -*- mode: c++; c-indent-level: 4; c++-member-init-indent: 8; comment-column: 35; -*-
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//-----------------------------------------------------------------------------
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// eoProportionalSelect.h
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// (c) GeNeura Team, 1998 - EEAAX 1999, Maarten Keijzer 2000
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/*
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This library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2 of the License, or (at your option) any later version.
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This library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with this library; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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Contact: todos@geneura.ugr.es, http://geneura.ugr.es
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Marc.Schoenauer@polytechnique.fr
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mak@dhi.dk
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*/
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//-----------------------------------------------------------------------------
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#ifndef eoProportionalSelect_h
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#define eoProportionalSelect_h
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//-----------------------------------------------------------------------------
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#include <iterator>
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#include <utility>
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#include "utils/eoRNG.h"
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#include "utils/selectors.h"
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#include "utils/eoLogger.h"
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#include "eoSelectOne.h"
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#include "eoPop.h"
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/** eoProportionalSelect: select an individual proportional to her stored fitness
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value
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Changed the algorithm to make use of a cumulative array of fitness scores,
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This changes the algorithm from O(n) per call to O(log n) per call. (MK)
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@ingroup Selectors
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*/
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template <class EOT>
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class eoProportionalSelect: public eoSelectOne<EOT>
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{
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public:
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/// Sanity check
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eoProportionalSelect(const eoPop<EOT>& /*pop*/ = eoPop<EOT>())
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{
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if (minimizing_fitness<EOT>()) {
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std::string msg = "eoProportionalSelect cannot be used with minimizing fitness";
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eo::log << eo::errors << "ERROR: " << msg << std::endl;
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throw eoException(msg);
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}
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}
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void setup(const eoPop<EOT>& _pop)
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{
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if (_pop.size() == 0) {
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eo::log << eo::warnings << "Warning: eoProportionalSelect setup called on an empty population." << std::endl;
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return;
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}
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assert(not _pop[0].invalid());
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const typename EOT::Fitness min_fit
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= std::min_element( std::begin(_pop), std::end(_pop) )
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->fitness();
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cumulative.clear();
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cumulative.push_back(_pop[0].fitness() - min_fit);
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for (unsigned i = 1; i < _pop.size(); ++i) {
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assert(not _pop[i].invalid());
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cumulative.push_back(cumulative.back() + _pop[i].fitness() - min_fit);
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}
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assert(cumulative.size() == _pop.size());
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}
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/** do the selection,
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*/
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const EOT& operator()(const eoPop<EOT>& _pop)
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{
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if (cumulative.size() == 0) setup(_pop);
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double frac = rng.uniform();
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double fortune = frac * cumulative.back();
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typename FitVec::iterator result
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= std::upper_bound(cumulative.begin(), cumulative.end(), fortune);
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// assert(fortune <= cumulative.back());
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if(static_cast<size_t>(result - cumulative.begin()) >= _pop.size()) {
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return _pop.back();
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} else {
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return _pop[result - cumulative.begin()];
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}
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}
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private :
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typedef std::vector<typename EOT::Fitness> FitVec;
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FitVec cumulative;
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public:
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virtual std::string className() const {return "eoProportionalSelect";}
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};
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/** @example t-eoRoulette.cpp
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*/
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#endif
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