SingleSpeciation.java

/*
 * Artificial Intelligence for Humans
 * Volume 2: Nature Inspired Algorithms
 * Java Version
 * http://www.aifh.org
 * http://www.jeffheaton.com
 *
 * Code repository:
 * https://github.com/jeffheaton/aifh
 *
 * Copyright 2014 by Jeff Heaton
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 * For more information on Heaton Research copyrights, licenses
 * and trademarks visit:
 * http://www.heatonresearch.com/copyright
 */
package com.heatonresearch.aifh.evolutionary.species;

import com.heatonresearch.aifh.AIFHError;
import com.heatonresearch.aifh.evolutionary.genome.Genome;
import com.heatonresearch.aifh.evolutionary.sort.SortGenomesForSpecies;
import com.heatonresearch.aifh.evolutionary.train.EvolutionaryAlgorithm;

import java.util.Collections;
import java.util.List;

/**
 * This speciation strategy simply creates a single species that contains the
 * entire population. Use this speciation strategy if you do not wish to use
 * species.
 */
public class SingleSpeciation implements Speciation {

    /**
     * The trainer.
     */
    private EvolutionaryAlgorithm owner;

    /**
     * The method used to sort the genomes in the species. More desirable
     * genomes should come first for later selection.
     */
    private SortGenomesForSpecies sortGenomes;

    /**
     * {@inheritDoc}
     */
    @Override
    public void init(final EvolutionaryAlgorithm theOwner) {
        this.owner = theOwner;
        this.sortGenomes = new SortGenomesForSpecies(this.owner);
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public void performSpeciation(final List<Genome> genomeList) {
        updateShare();
        final Species species = this.owner.getPopulation().getSpecies().get(0);
        species.getMembers().clear();
        species.getMembers().addAll(genomeList);
        Collections.sort(species.getMembers(), this.sortGenomes);
        species.setLeader(species.getMembers().get(0));

    }

    /**
     * Update the species share of the next population.
     */
    private void updateShare() {
        final int speciesCount = this.owner.getPopulation().getSpecies().size();
        if (speciesCount != 1) {
            throw new AIFHError(
                    "SingleSpeciation can only be used with a species count of 1, species count is "
                            + speciesCount);
        }

        final Species species = this.owner.getPopulation().getSpecies().get(0);
        species.setOffspringCount(this.owner.getPopulation()
                .getPopulationSize());
    }

}