001package org.cpsolver.coursett.criteria.placement;
002
003import java.util.Set;
004
005import org.cpsolver.coursett.model.Lecture;
006import org.cpsolver.coursett.model.Placement;
007import org.cpsolver.ifs.assignment.Assignment;
008import org.cpsolver.ifs.util.DataProperties;
009
010
011/**
012 * Difference between proposed and best time assignment. Time assignments
013 * that are do not maximize time preference are penalized by the difference
014 * in the preference.
015 * <br>
016 * 
017 * @version CourseTT 1.3 (University Course Timetabling)<br>
018 *          Copyright (C) 2006 - 2014 Tomáš Müller<br>
019 *          <a href="mailto:muller@unitime.org">muller@unitime.org</a><br>
020 *          <a href="http://muller.unitime.org">http://muller.unitime.org</a><br>
021 * <br>
022 *          This library is free software; you can redistribute it and/or modify
023 *          it under the terms of the GNU Lesser General Public License as
024 *          published by the Free Software Foundation; either version 3 of the
025 *          License, or (at your option) any later version. <br>
026 * <br>
027 *          This library is distributed in the hope that it will be useful, but
028 *          WITHOUT ANY WARRANTY; without even the implied warranty of
029 *          MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
030 *          Lesser General Public License for more details. <br>
031 * <br>
032 *          You should have received a copy of the GNU Lesser General Public
033 *          License along with this library; if not see
034 *          <a href='http://www.gnu.org/licenses/'>http://www.gnu.org/licenses/</a>.
035 */
036public class DeltaTimePreference extends PlacementSelectionCriterion {
037    private double iLevel1DefaultWeight = 0.0;
038    
039    @Override
040    public void configure(DataProperties properties) {   
041        super.configure(properties);
042        iLevel1DefaultWeight = properties.getPropertyDouble("Comparator.TimePreferenceWeight", 1.0) / 2.0;
043    }
044
045    @Override
046    public String getPlacementSelectionWeightName() {
047        return "Placement.DeltaTimePreferenceWeight";
048    }
049
050    @Override
051    public double getValue(Assignment<Lecture, Placement> assignment, Placement value, Set<Placement> conflicts) {
052        double ret = value.variable().getWeight() * (value.getTimeLocation().getNormalizedPreference() - value.variable().getBestTimePreference());
053        if (conflicts != null)
054            for (Placement placement : conflicts) {
055                double timePref = placement.getTimeLocation().getNormalizedPreference();
056                ret -= placement.variable().getWeight() * (timePref - placement.variable().getBestTimePreference());
057            }
058        return ret;
059    }
060
061    @Override
062    public double getPlacementSelectionWeightDefault(int level) {
063        return (level == 0 ? iLevel1DefaultWeight : 0.0);
064    }
065}