    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 * @author  Tomáš Müller
    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 DeltaTimePreference extends PlacementSelectionCriterion {
    038    private double iLevel1DefaultWeight = 0.0;
    039
    040    @Override
    041    public void configure(DataProperties properties) {
    042        super.configure(properties);
    043        iLevel1DefaultWeight = properties.getPropertyDouble("Comparator.TimePreferenceWeight", 1.0) / 2.0;
    044    }
    045
    046    @Override
    047    public String getPlacementSelectionWeightName() {
    048        return "Placement.DeltaTimePreferenceWeight";
    049    }
    050
    051    @Override
    052    public double getValue(Assignment<Lecture, Placement> assignment, Placement value, Set<Placement> conflicts) {
    053        double ret = value.variable().getWeight() * (value.getTimeLocation().getNormalizedPreference() - value.variable().getBestTimePreference());
    054        if (conflicts != null)
    055            for (Placement placement : conflicts) {
    056                double timePref = placement.getTimeLocation().getNormalizedPreference();
    057                ret -= placement.variable().getWeight() * (timePref - placement.variable().getBestTimePreference());
    058            }
    059        return ret;
    060    }
    061
    062    @Override
    063    public double getPlacementSelectionWeightDefault(int level) {
    064        return (level == 0 ? iLevel1DefaultWeight : 0.0);
    065    }
    066}