97 lines
2.6 KiB
C++
97 lines
2.6 KiB
C++
/*
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(c) Thales group, 2010
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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;
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version 2 of the License.
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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: http://eodev.sourceforge.net
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Authors:
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Lionel Parreaux <lionel.parreaux@gmail.com>
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*/
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#ifndef moFitnessVarianceStat_h
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#define moFitnessVarianceStat_h
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#include <continuator/moStat.h>
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/**
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* Statistic that incrementally computes the variance of the fitness of the solutions during the search
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*/
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template <class EOT>
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class moFitnessVarianceStat : public moStat<EOT, typename EOT::Fitness>
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{
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public :
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typedef typename EOT::Fitness Fitness;
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using moStat< EOT , typename EOT::Fitness >::value;
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/**
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* Default Constructor
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* @param _reInitSol when true the best so far is reinitialized
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*/
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moFitnessVarianceStat(bool _reInitSol = true)
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: moStat<EOT, typename EOT::Fitness>(Fitness(), "var"),
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reInitSol(_reInitSol), firstTime(true),
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nbSolutionsEncountered(0), currentAvg(0), currentVar(0)
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{ }
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/**
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* Initialization of the best solution on the first one
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* @param _sol the first solution
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*/
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virtual void init(EOT & _sol) {
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if (reInitSol || firstTime)
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{
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value() = 0.0;
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nbSolutionsEncountered = currentAvg = currentVar = 0;
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firstTime = false;
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}
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operator()(_sol);
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}
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/**
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* Update the best solution
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* @param _sol the current solution
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*/
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virtual void operator()(EOT & _sol) {
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++nbSolutionsEncountered;
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double x = _sol.fitness();
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double oldAvg = currentAvg;
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currentAvg = oldAvg + (x - oldAvg)/nbSolutionsEncountered;
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double oldVar = currentVar;
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currentVar = oldVar + (x - oldAvg) * (x - currentAvg);
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value() = currentVar/nbSolutionsEncountered;
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}
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/**
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* @return name of the class
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*/
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virtual std::string className(void) const {
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return "moFitnessVarianceStat";
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}
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protected:
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bool reInitSol;
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bool firstTime;
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double
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nbSolutionsEncountered
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, currentAvg
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, currentVar // actually the var * n
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;
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};
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#endif // moFitnessVarianceStat_h
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