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.coursett.model.TimeLocation;
009import org.cpsolver.ifs.assignment.Assignment;
010import org.cpsolver.ifs.util.DataProperties;
011
012
013/**
014 * Time preferences. This criterion counts how well the time preferences are met. This is
015 * a sum of {@link TimeLocation#getNormalizedPreference()} of the assigned classes.
016 * <br>
017 * 
018 * @version CourseTT 1.3 (University Course Timetabling)<br>
019 *          Copyright (C) 2006 - 2014 Tomáš Müller<br>
020 *          <a href="mailto:muller@unitime.org">muller@unitime.org</a><br>
021 *          <a href="http://muller.unitime.org">http://muller.unitime.org</a><br>
022 * <br>
023 *          This library is free software; you can redistribute it and/or modify
024 *          it under the terms of the GNU Lesser General Public License as
025 *          published by the Free Software Foundation; either version 3 of the
026 *          License, or (at your option) any later version. <br>
027 * <br>
028 *          This library is distributed in the hope that it will be useful, but
029 *          WITHOUT ANY WARRANTY; without even the implied warranty of
030 *          MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
031 *          Lesser General Public License for more details. <br>
032 * <br>
033 *          You should have received a copy of the GNU Lesser General Public
034 *          License along with this library; if not see
035 *          <a href='http://www.gnu.org/licenses/'>http://www.gnu.org/licenses/</a>.
036 */
037public class TimePreferences extends TimetablingCriterion {
038
039    @Override
040    public double getWeightDefault(DataProperties config) {
041        return config.getPropertyDouble("Comparator.TimePreferenceWeight", 1.0);
042    }
043
044    @Override
045    public String getPlacementSelectionWeightName() {
046        return "Placement.TimePreferenceWeight";
047    }
048    
049    private double preference(Placement value) {
050        return value.getTimePenalty();
051    }
052
053    @Override
054    public double getValue(Assignment<Lecture, Placement> assignment, Placement value, Set<Placement> conflicts) {
055        if (value.variable().isCommitted()) return 0.0;
056        double ret = value.variable().getWeight() * preference(value);
057        if (conflicts != null)
058            for (Placement conflict: conflicts)
059                ret -= conflict.variable().getWeight() * preference(conflict);
060        return ret;
061    }
062        
063    @Override
064    public double[] getBounds(Assignment<Lecture, Placement> assignment, Collection<Lecture> variables) {
065        double[] bounds = new double[] { 0.0, 0.0 };
066        for (Lecture lect: variables) {
067            if (lect.isCommitted()) continue;
068            double[] p = lect.getMinMaxTimePreference();
069            bounds[1] += lect.getWeight() * (p[1] - p[0]);
070        }
071        return bounds;
072    }
073
074}