it.units.malelab.ege.ge.operator.BitsSGECrossover.java Source code

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Here is the source code for it.units.malelab.ege.ge.operator.BitsSGECrossover.java

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package it.units.malelab.ege.ge.operator;

import it.units.malelab.ege.core.operator.AbstractCrossover;
import com.google.common.collect.Range;
import it.units.malelab.ege.ge.genotype.BitsGenotype;
import it.units.malelab.ege.ge.mapper.BitsSGEMapper;
import it.units.malelab.ege.util.Utils;
import java.util.Arrays;
import java.util.List;
import java.util.Random;

/**
 *
 * @author eric
 */
public class BitsSGECrossover extends AbstractCrossover<BitsGenotype> {

    private final List<Integer> nonTerminalSizes;
    private int overallSize;

    public BitsSGECrossover(BitsSGEMapper sgeMapper) {
        nonTerminalSizes = sgeMapper.getNonTerminalSizes();
        overallSize = 0;
        for (int size : nonTerminalSizes) {
            overallSize = overallSize + size;
        }
    }

    @Override
    public List<BitsGenotype> apply(List<BitsGenotype> parents, Random random) {
        BitsGenotype parent1 = parents.get(0);
        BitsGenotype parent2 = parents.get(1);
        if (Math.min(parent1.size(), parent2.size()) < overallSize) {
            //should be an exception
            return parents;
        }
        int nonTerminalIndex = random.nextInt(nonTerminalSizes.size());
        List<BitsGenotype> parent1Slices = parent1
                .slices(Utils.slices(Range.closedOpen(0, parent1.size()), nonTerminalSizes));
        List<BitsGenotype> parent2Slices = parent2
                .slices(Utils.slices(Range.closedOpen(0, parent2.size()), nonTerminalSizes));
        BitsGenotype child1 = new BitsGenotype(0);
        BitsGenotype child2 = new BitsGenotype(0);
        for (int i = 0; i < parent1Slices.size(); i++) {
            child1 = child1.append(((i == nonTerminalIndex) ? parent2Slices : parent1Slices).get(i));
            child2 = child2.append(((i == nonTerminalIndex) ? parent1Slices : parent2Slices).get(i));
        }
        return Arrays.asList(child1, child2);
    }

}