001package org.cpsolver.coursett.criteria;
002
003import java.util.Collection;
004import java.util.Set;
005
006import org.cpsolver.coursett.model.Lecture;
007import org.cpsolver.coursett.model.Placement;
008import org.cpsolver.ifs.assignment.Assignment;
009import org.cpsolver.ifs.perturbations.PerturbationsCounter;
010import org.cpsolver.ifs.solver.Solver;
011import org.cpsolver.ifs.util.DataProperties;
012
013
014/**
015 * Perturbations. This criterion counts differences (perturbations) between initial and the current
016 * solution. It is based on {@link PerturbationsCounter}.
017 * <br>
018 * 
019 * @version CourseTT 1.3 (University Course Timetabling)<br>
020 *          Copyright (C) 2006 - 2014 Tomáš Müller<br>
021 *          <a href="mailto:muller@unitime.org">muller@unitime.org</a><br>
022 *          <a href="http://muller.unitime.org">http://muller.unitime.org</a><br>
023 * <br>
024 *          This library is free software; you can redistribute it and/or modify
025 *          it under the terms of the GNU Lesser General Public License as
026 *          published by the Free Software Foundation; either version 3 of the
027 *          License, or (at your option) any later version. <br>
028 * <br>
029 *          This library is distributed in the hope that it will be useful, but
030 *          WITHOUT ANY WARRANTY; without even the implied warranty of
031 *          MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
032 *          Lesser General Public License for more details. <br>
033 * <br>
034 *          You should have received a copy of the GNU Lesser General Public
035 *          License along with this library; if not see
036 *          <a href='http://www.gnu.org/licenses/'>http://www.gnu.org/licenses/</a>.
037 */
038
039public class Perturbations extends TimetablingCriterion {
040    private PerturbationsCounter<Lecture, Placement> iPerturbationsCounter = null;
041    
042    public Perturbations() {
043        setValueUpdateType(ValueUpdateType.NoUpdate);
044    }
045    
046    @Override
047    public String getPlacementSelectionWeightName() {
048        return "Placement.MPP_DeltaInitialAssignmentWeight";
049    }
050
051    @Override
052    public boolean init(Solver<Lecture, Placement> solver) {
053        iPerturbationsCounter = solver.getPerturbationsCounter();
054        return super.init(solver);
055    }
056    
057    @Override
058    public double getWeightDefault(DataProperties config) {
059        return config.getPropertyDouble("Comparator.PerturbationPenaltyWeight", 1.0);
060    }
061    
062    public PerturbationsCounter<Lecture, Placement> getPerturbationsCounter() {
063        return iPerturbationsCounter;
064    }
065
066    @Override
067    public double getValue(Assignment<Lecture, Placement> assignment, Placement value, Set<Placement> conflicts) {
068        return getPerturbationsCounter().getPerturbationPenalty(assignment, getModel(), value, conflicts);
069    }
070    
071    @Override
072    public double getValue(Assignment<Lecture, Placement> assignment) {
073        return getPerturbationsCounter().getPerturbationPenalty(assignment, getModel());
074    }
075
076    @Override
077    public double getValue(Assignment<Lecture, Placement> assignment, Collection<Lecture> variables) {
078        return getPerturbationsCounter().getPerturbationPenalty(assignment, getModel(), variables);
079    }
080
081    @Override
082    public double[] getBounds(Assignment<Lecture, Placement> assignment) {
083        return new double[] { 0.0, 0.0 };
084    }
085    
086    @Override
087    public double[] getBounds(Assignment<Lecture, Placement> assignment, Collection<Lecture> variables) {
088        return new double[] { 0.0, 0.0 };
089    }
090}