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 * @author  Tomáš Müller
020 * @version CourseTT 1.3 (University Course Timetabling)<br>
021 *          Copyright (C) 2006 - 2014 Tomáš Müller<br>
022 *          <a href="mailto:muller@unitime.org">muller@unitime.org</a><br>
023 *          <a href="http://muller.unitime.org">http://muller.unitime.org</a><br>
024 * <br>
025 *          This library is free software; you can redistribute it and/or modify
026 *          it under the terms of the GNU Lesser General Public License as
027 *          published by the Free Software Foundation; either version 3 of the
028 *          License, or (at your option) any later version. <br>
029 * <br>
030 *          This library is distributed in the hope that it will be useful, but
031 *          WITHOUT ANY WARRANTY; without even the implied warranty of
032 *          MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
033 *          Lesser General Public License for more details. <br>
034 * <br>
035 *          You should have received a copy of the GNU Lesser General Public
036 *          License along with this library; if not see
037 *          <a href='http://www.gnu.org/licenses/'>http://www.gnu.org/licenses/</a>.
038 */
039
040public class Perturbations extends TimetablingCriterion {
041    private PerturbationsCounter<Lecture, Placement> iPerturbationsCounter = null;
042    
043    public Perturbations() {
044        setValueUpdateType(ValueUpdateType.NoUpdate);
045    }
046    
047    @Override
048    public String getPlacementSelectionWeightName() {
049        return "Placement.MPP_DeltaInitialAssignmentWeight";
050    }
051
052    @Override
053    public boolean init(Solver<Lecture, Placement> solver) {
054        iPerturbationsCounter = solver.getPerturbationsCounter();
055        return super.init(solver);
056    }
057    
058    @Override
059    public double getWeightDefault(DataProperties config) {
060        return config.getPropertyDouble("Comparator.PerturbationPenaltyWeight", 1.0);
061    }
062    
063    public PerturbationsCounter<Lecture, Placement> getPerturbationsCounter() {
064        return iPerturbationsCounter;
065    }
066
067    @Override
068    public double getValue(Assignment<Lecture, Placement> assignment, Placement value, Set<Placement> conflicts) {
069        return getPerturbationsCounter().getPerturbationPenalty(assignment, getModel(), value, conflicts);
070    }
071    
072    @Override
073    public double getValue(Assignment<Lecture, Placement> assignment) {
074        return getPerturbationsCounter().getPerturbationPenalty(assignment, getModel());
075    }
076
077    @Override
078    public double getValue(Assignment<Lecture, Placement> assignment, Collection<Lecture> variables) {
079        return getPerturbationsCounter().getPerturbationPenalty(assignment, getModel(), variables);
080    }
081
082    @Override
083    public double[] getBounds(Assignment<Lecture, Placement> assignment) {
084        return new double[] { 0.0, 0.0 };
085    }
086    
087    @Override
088    public double[] getBounds(Assignment<Lecture, Placement> assignment, Collection<Lecture> variables) {
089        return new double[] { 0.0, 0.0 };
090    }
091}