001 package net.sf.cpsolver.coursett.criteria.placement;
002
003 import java.util.Set;
004
005 import net.sf.cpsolver.coursett.model.Lecture;
006 import net.sf.cpsolver.coursett.model.Placement;
007 import net.sf.cpsolver.ifs.solver.Solver;
008
009 /**
010 * Difference between proposed and best time assignment. Time assignments
011 * that are do not maximize time preference are penalized by the difference
012 * in the preference.
013 * <br>
014 *
015 * @version CourseTT 1.2 (University Course Timetabling)<br>
016 * Copyright (C) 2006 - 2011 Tomas Muller<br>
017 * <a href="mailto:muller@unitime.org">muller@unitime.org</a><br>
018 * <a href="http://muller.unitime.org">http://muller.unitime.org</a><br>
019 * <br>
020 * This library is free software; you can redistribute it and/or modify
021 * it under the terms of the GNU Lesser General Public License as
022 * published by the Free Software Foundation; either version 3 of the
023 * License, or (at your option) any later version. <br>
024 * <br>
025 * This library is distributed in the hope that it will be useful, but
026 * WITHOUT ANY WARRANTY; without even the implied warranty of
027 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
028 * Lesser General Public License for more details. <br>
029 * <br>
030 * You should have received a copy of the GNU Lesser General Public
031 * License along with this library; if not see
032 * <a href='http://www.gnu.org/licenses/'>http://www.gnu.org/licenses/</a>.
033 */
034 public class DeltaTimePreference extends PlacementSelectionCriterion {
035 private double iLevel1DefaultWeight = 0.0;
036
037 @Override
038 public boolean init(Solver<Lecture, Placement> solver) {
039 iLevel1DefaultWeight = solver.getProperties().getPropertyDouble("Comparator.TimePreferenceWeight", 1.0) / 2.0;
040 return super.init(solver);
041 }
042
043 @Override
044 public String getPlacementSelectionWeightName() {
045 return "Placement.DeltaTimePreferenceWeight";
046 }
047
048 @Override
049 public double getValue(Placement value, Set<Placement> conflicts) {
050 double ret = value.getTimeLocation().getNormalizedPreference() - value.variable().getBestTimePreference();
051 if (conflicts != null)
052 for (Placement placement : conflicts) {
053 double timePref = placement.getTimeLocation().getNormalizedPreference();
054 ret -= timePref - placement.variable().getBestTimePreference();
055 }
056 return ret;
057 }
058
059 @Override
060 public double getPlacementSelectionWeightDefault(int level) {
061 return (level == 0 ? iLevel1DefaultWeight : 0.0);
062 }
063 }