nsga2.h

/********************************************************************************
 *  FARSA Genetic Algorithm Library                                             *
 *  Copyright (C) 2007-2011 Gianluca Massera <emmegian@yahoo.it>                *
 *                                                                              *
 *  This program is free software; you can redistribute it and/or modify        *
 *  it under the terms of the GNU General Public License as published by        *
 *  the Free Software Foundation; either version 2 of the License, or           *
 *  (at your option) any later version.                                         *
 *                                                                              *
 *  This program 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 General Public License for more details.                                *
 *                                                                              *
 *  You should have received a copy of the GNU General Public License           *
 *  along with this program; if not, write to the Free Software                 *
 *  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA  *
 ********************************************************************************/

#ifndef NSGA2_H
#define NSGA2_H

#include "gaconfig.h"
#include "core/geneticalgo.h"
#include "core/genotype.h"
#include "core/genome.h"
#include <QList>

namespace farsa {

class Evaluation;
class Reproduction;

class FARSA_GA_API NSGA2 : public GeneticAlgo {
public:
    NSGA2();
    virtual ~NSGA2();
    void setNumThreads( int numThreads );
    int numThreads();
    void setEvaluation( Evaluation* fitfunc );
    virtual Evaluation* evaluationPrototype();
    virtual QVector<Evaluation*> evaluationPool();
    void setReproduction( Reproduction* reproduct );
    Reproduction* reproduction();
    virtual void initialize();
    virtual void gaStep();
    virtual void finalize();

    virtual void skipEvaluation();

    virtual void configure( ConfigurationParameters& params, QString prefix );
    virtual void save( ConfigurationParameters& params, QString prefix );
    static void describe( QString type );

protected:
    Evaluation* fitfunc;
    Reproduction* reprod;
    typedef enum { initEvaluation, evaluating, nextGeneration_pass1, nextGeneration_pass2, endEvolution } GAPhases;
    GAPhases currPhase;
    bool isInitialized;
    bool isFinalized;

private:
    bool nextGeneration;
    
    class nsgaGenotype {
    public:
        nsgaGenotype( Genotype* g=NULL, int rank=0, double distance=0 ) {
            genotype = g;
            this->rank = rank;
            this->distance = distance;
        };
        Genotype* genotype;
        int rank;
        double distance;
        int dominationCounter;
        bool operator<( const nsgaGenotype& g ) const {
            return this->distance < g.distance;
        };
        bool operator==( const nsgaGenotype& g ) const {
            return this->genotype == g.genotype;
        };
    };
    typedef QVector<nsgaGenotype*> nsgaGenome;
    Genome lastPareto;
    void crowdingDistanceAssignment( nsgaGenome& genome );
    QVector<nsgaGenome> fastNonDominatedSort( nsgaGenome& pareto );
    static bool crowdingDistanceGreaterThan( const nsgaGenotype* g1, const nsgaGenotype* g2 ) {
        return g1->distance > g2->distance;
    };
    class nObjectiveGreaterThan {
    public:
        bool operator()( const nsgaGenotype* g1, const nsgaGenotype* g2 ) {
            return g1->genotype->objective( currentObjective ) > g2->genotype->objective( currentObjective );
        };
        int currentObjective;   
    };

    class evaluationThread {
    public:
        //--- Constructor
        evaluationThread( NSGA2* p, Evaluation* eProto );
        //--- Destructor
        ~evaluationThread();
        //--- LaralGA parent
        NSGA2* parent;
        //--- evaluator used by this object
        Evaluation* eval;
        //--- evaluating genoma
        int id;
        //--- true when it cannot increment id because the end is reached
        bool blocked;
        //--- run a step of evaluation
        void runStep();
        //--- sequence of Genoma to evaluate
        QVector<int> sequence;
        //--- actual id inside sequence in evaluating
        int idSeq;
    };

    QList<evaluationThread*> evalThreads;
    int numThreadv;
    static void runStepWrapper( NSGA2::evaluationThread* e );
};

} // end namespace farsa

#endif