net.sourceforge.cilib.moo.archive.constrained.SetBasedConstrainedArchive Maven / Gradle / Ivy

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/**           __  __
 *    _____ _/ /_/ /_    Computational Intelligence Library (CIlib)
 *   / ___/ / / / __ \   (c) CIRG @ UP
 *  / /__/ / / / /_/ /   http://cilib.net
 *  \___/_/_/_/_.___/
 */
package net.sourceforge.cilib.moo.archive.constrained;

import com.google.common.collect.Lists;
import com.google.common.collect.Sets;
import java.util.Collection;
import java.util.List;
import java.util.Set;
import net.sourceforge.cilib.moo.archive.Archive;
import net.sourceforge.cilib.problem.solution.OptimisationSolution;
import net.sourceforge.cilib.util.selection.Selection;
import net.sourceforge.cilib.util.selection.recipes.DistanceBasedElitistSelector;
import net.sourceforge.cilib.util.selection.recipes.Selector;

/**
 *  A constrained set-driven {@link Archive} implementation. It makes use of
 * a {@link Selection} to determine which solution from the archive will be
 * selected next for removal if the archive grows larger than the capacity. 
 *
 */
public class SetBasedConstrainedArchive extends ConstrainedArchive {

    private Set solutions;
    private Selector pruningSelection;

    public SetBasedConstrainedArchive() {
        this.solutions = Sets.newLinkedHashSet();
        this.pruningSelection = new DistanceBasedElitistSelector();
    }

    public SetBasedConstrainedArchive(SetBasedConstrainedArchive copy) {
        super(copy);
        this.solutions = Sets.newLinkedHashSet();
        for (OptimisationSolution solution : copy.solutions) {
            this.solutions.add(solution.getClone());
        }
        this.pruningSelection = copy.pruningSelection;
    }

    public void setPruningSelection(Selector pruningSelection) {
        this.pruningSelection = pruningSelection;
    }

    public Selector getPruningSelection() {
        return this.pruningSelection;
    }

    @Override
    public boolean dominates(OptimisationSolution candidateSolution) {
        for (OptimisationSolution archiveSolution : this.solutions) {
            if (archiveSolution.compareTo(candidateSolution) > 0) {
                return true;
            }
        }
        return false;
    }

    @Override
    public boolean isDominatedBy(OptimisationSolution candidateSolution) {
        for (OptimisationSolution archiveSolution : this.solutions) {
            if (candidateSolution.compareTo(archiveSolution) > 0) {
                return true;
            }
        }
        return false;
    }

    @Override
    public Collection getDominant(OptimisationSolution candidateSolution) {
        List dominantSolutions = Lists.newLinkedList();
        for (OptimisationSolution archiveSolution : this.solutions) {
            if (archiveSolution.compareTo(candidateSolution) > 0) {
                dominantSolutions.add(archiveSolution);
            }
        }
        return dominantSolutions;
    }

    @Override
    public Collection getDominated(OptimisationSolution candidateSolution) {
        List dominatedSolutions = Lists.newLinkedList();
        for (OptimisationSolution archiveSolution : this.solutions) {
            if (candidateSolution.compareTo(archiveSolution) > 0) {
                dominatedSolutions.add(archiveSolution);
            }
        }
        return dominatedSolutions;
    }

    @Override
    protected void prune() {
        // If the archive size is greater than the capacity, select a group of solutions and remove them from the archive.
        int numSolutionsToRemove = size() - getCapacity();
        for (int i = 0; i < numSolutionsToRemove; ++i) {
            OptimisationSolution solutionToRemove = this.pruningSelection.on(this).select();
            remove(solutionToRemove);
        }
    }

    @Override
    public boolean addToStructure(OptimisationSolution optimisationSolution) {
        return this.solutions.add(optimisationSolution);
    }

    @Override
    protected Collection delegate() {
        return this.solutions;
    }
}