ga/src/gas/stefanosteadystatega.cpp

/********************************************************************************
 *  FARSA Genetic Algorithm Library                                             *
 *  Copyright (C) 2007-2009 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  *
 ********************************************************************************/

#include "factory.h"
#include "gas/stefanosteadystatega.h"
#include "core/reproduction.h"
#include "core/genome.h"
#include "core/evaluation.h"
#include "logger.h"
#include <QThreadPool>
#include <QtConcurrentMap>
using namespace QtConcurrent;

namespace farsa {

StefanoSteadyStateGA::StefanoSteadyStateGA() :
    GeneticAlgo(),
    fitfunc(NULL),
    muta(NULL),
    curPhase(initParent),
    curGenotype(0),
    isInitialized(false),
    isFinalized(true),
    numEvaluations(),
    cumulatedFitness(),
    offspring(NULL)
{
}

StefanoSteadyStateGA::~StefanoSteadyStateGA() {
    delete fitfunc;
    delete muta;
}

void StefanoSteadyStateGA::configure( ConfigurationParameters& params, QString prefix ) {
    setGenome( params.getObjectFromGroup<Genome>( prefix + QString( "GENOME" ) ) );
    setEvaluation( params.getObjectFromGroup<Evaluation>( prefix + QString( "EVALUATION" ) ) );
    fitfunc->setGenome( genome() );
    setMutation( params.getObjectFromGroup<Mutation>( prefix + QString( "MUTATION" ) ) );
    setNumGenerations( params.getValue( prefix + QString( "ngenerations" ) ).toInt() );
    if ( numGenerations() == 0 ) {
        Logger::warning( "StefanoSteadyStateGA: Setting number of Generations to ZERO!! Check your config file" );
    }
}

void StefanoSteadyStateGA::save( ConfigurationParameters& params, QString prefix ) {
    params.createParameter( prefix, QString("type"), "StefanoSteadyStateGA" );
    params.createParameter( prefix, QString("ngenerations"), QString("%1").arg( numGenerations() ) );
    //--- EVALUATION
    fitfunc->save( params, params.createSubGroup( prefix, "EVALUATION" ) );
    //--- MUTATION
    mutation()->save( params, params.createSubGroup( prefix, "MUTATION" ) );
    //--- GENOME
    genome()->save( params, params.createSubGroup( prefix, "GENOME" ) );
}

void StefanoSteadyStateGA::describe( QString type ) {
    Descriptor d = addTypeDescription( type, "A variant of Steady State Genetic Algorithm developed by Stefano Nolfi" );
    d.describeInt( "numThreads" ).limits( 1, 32 ).help( "Number of threads to parallelize the evaluation of individuals" );
    d.describeInt( "ngenerations" ).limits( 1, MaxInteger ).def( 1000 ).help( "Number of the generations of the evolutionary process" );
    d.describeSubgroup( "EVALUATION" ).type( "Evaluation" ).props( IsMandatory ).help( "Object that calculate the fitness", "Create a subclass of Evalution and code your custom fitness function" );
    d.describeSubgroup( "MUTATION").type( "Mutation" ).props( IsMandatory ).help( "Object that mutate the genotype of an individual" );
    d.describeSubgroup( "GENOME" ).type( "Genome" ).props( IsMandatory ).help( "Object containing the individuals under evolution" );
}

void StefanoSteadyStateGA::setEvaluation( Evaluation* fitfunc ) {
    this->fitfunc = fitfunc;
    this->fitfunc->setGA( this );
}

Evaluation* StefanoSteadyStateGA::evaluationPrototype()
{
    return fitfunc;
}

QVector<Evaluation*> StefanoSteadyStateGA::evaluationPool() {
    // For the moment we only have one evaluator (no threads)
    QVector<Evaluation*> ev;
    ev.append(fitfunc);
    return ev;
}

void StefanoSteadyStateGA::setMutation( Mutation* mutation ) {
    this->muta = mutation;
    this->muta->setGA( this );
}

Mutation* StefanoSteadyStateGA::mutation() {
    return muta;
}

void StefanoSteadyStateGA::initialize() {
    if ( isInitialized && !isFinalized ) return;
    Q_ASSERT_X( fitfunc != 0 ,
            "StefanoSteadyStateGA::initialize",
            "You have to setup the Evaluation object of StefanoSteadyStateGA (Fitness Function)" );
    Q_ASSERT_X( muta !=0 ,
            "StefanoSteadyStateGA::initialize",
            "You have to setup the Mutation operator of StefanoSteadyStateGA" );

    isInitialized = true;
    isFinalized = false;
    setGeneration(0);
    curPhase = initParent;
    curGenotype = 0;
    evolutionEnd = false;
    evaluationDone = false;
    delete offspring;
    offspring = NULL;

    // Initializing mutation and evaluator
    muta->setGenome(genome());
    fitfunc->setGenome(genome());
    numEvaluations.fill(0, genome()->size());
    cumulatedFitness.fill(0.0, genome()->size());
}

void StefanoSteadyStateGA::gaStep() {
    switch (curPhase) {
        case initParent:
            {
                fitfunc->initialize(genome()->at(curGenotype));
                curPhase = evalParent;
            }
            break;
        case evalParent:
            {
                fitfunc->evaluateStep();
                if (fitfunc->isEvaluationDone()) {
                    fitfunc->finalize();
                    cumulatedFitness[curGenotype] += fitfunc->genotype()->fitness();
                    numEvaluations[curGenotype]++;
                    fitfunc->genotype()->setRank(cumulatedFitness[curGenotype] / double(numEvaluations[curGenotype]));
                    curPhase = initOffspring;
                }
            }
            break;
        case initOffspring:
            {
                // Generating one offspring of the current genome
                delete offspring;
                offspring = genome()->at(curGenotype)->clone();
                muta->mutate(offspring);
                fitfunc->initialize(offspring);
                curPhase = evalOffspring;
            }
            break;
        case evalOffspring:
            {
                fitfunc->evaluateStep();
                if (fitfunc->isEvaluationDone()) {
                    fitfunc->finalize();
                    offspring->setRank(offspring->fitness());
                    curPhase = compareOffspring;
                }
            }
            break;
        case compareOffspring:
            {
                // Replacing the individual with the lowest fitness with the offspring. First searching
                // the worst genome...
                unsigned int worstGenome = 0;
                double worstGenomeFitness = genome()->at(0)->rank();
                for (unsigned int i = 1; i < genome()->size(); i++) {
                    if (numEvaluations[i] == 0) {
                        continue;
                    }
                    if (genome()->at(i)->rank() < worstGenomeFitness) {
                        worstGenome = i;
                        worstGenomeFitness = genome()->at(i)->rank();
                    }
                }
                // ... now checking if the worst genome is worse than the offspring. If so, swapping
                if (worstGenomeFitness < offspring->rank()) {
                    *(genome()->at(worstGenome)) = *offspring;
                    cumulatedFitness[worstGenome] = offspring->rank();
                    numEvaluations[worstGenome] = 1;
                }
                if (curGenotype < (genome()->size() - 1)) {
                    curGenotype++;
                    curPhase = initParent;
                } else {
                    evaluationDone = true;
                    curPhase = nextGeneration;
                }
            }
            break;
        case nextGeneration:
            {
                // We don't sort the genome, there is no need to
                updateStats();
                evaluationDone = false;
                if (generation() < numGens) {
                    curPhase = initParent;
                    setGeneration( generation()+1 );
                    curGenotype = 0;
                } else {
                    curPhase = endEvolution;
                }
            }
            break;
        case endEvolution:
            {
                finalize();
            }
            break;
        default:
            qFatal("Default switch in StefanoSteadyStateGA::gaStep");
            break;
    }
}

void StefanoSteadyStateGA::skipEvaluation() {
    // Set evaluation done, and set the new phase
    evaluationDone = true;
    curPhase = nextGeneration;
}

void StefanoSteadyStateGA::finalize() {
    if ( isFinalized && !isInitialized ) return;

    isInitialized = false;
    isFinalized = true;
    evolutionEnd = true;
    delete offspring;
    offspring = NULL;

    // Rank is already normalized

    // Finally sorting genome
    qSort( genome()->begin(), genome()->end(), Genotype::rankGreaterThanComparator );
}

} // end namespace farsa