001package net.sf.cpsolver.coursett.criteria.placement; 002 003import java.util.Set; 004 005import net.sf.cpsolver.coursett.model.Lecture; 006import net.sf.cpsolver.coursett.model.Placement; 007import 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 Tomáš Müller<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 */ 034public 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.variable().getWeight() * (value.getTimeLocation().getNormalizedPreference() - value.variable().getBestTimePreference()); 051 if (conflicts != null) 052 for (Placement placement : conflicts) { 053 double timePref = placement.getTimeLocation().getNormalizedPreference(); 054 ret -= placement.variable().getWeight() * (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}