001package net.sf.cpsolver.coursett.neighbourhoods; 002 003import java.util.List; 004 005import net.sf.cpsolver.coursett.model.Lecture; 006import net.sf.cpsolver.coursett.model.Placement; 007import net.sf.cpsolver.coursett.model.RoomLocation; 008import net.sf.cpsolver.coursett.model.TimeLocation; 009import net.sf.cpsolver.coursett.model.TimetableModel; 010import net.sf.cpsolver.ifs.algorithms.neighbourhoods.RandomMove; 011import net.sf.cpsolver.ifs.model.Neighbour; 012import net.sf.cpsolver.ifs.model.SimpleNeighbour; 013import net.sf.cpsolver.ifs.solution.Solution; 014import net.sf.cpsolver.ifs.util.DataProperties; 015import net.sf.cpsolver.ifs.util.ToolBox; 016 017/** 018 * Try to assign a class with a new time. A class is selected randomly, a 019 * different (available) time is randomly selected for the class -- the class is 020 * assigned into the new time if there is no conflict. 021 * <br> 022 * 023 * @version IFS 1.2 (Iterative Forward Search)<br> 024 * Copyright (C) 2014 Tomáš Müller<br> 025 * <a href="mailto:muller@unitime.org">muller@unitime.org</a><br> 026 * <a href="http://muller.unitime.org">http://muller.unitime.org</a><br> 027 * <br> 028 * This library is free software; you can redistribute it and/or modify 029 * it under the terms of the GNU Lesser General Public License as 030 * published by the Free Software Foundation; either version 3 of the 031 * License, or (at your option) any later version. <br> 032 * <br> 033 * This library is distributed in the hope that it will be useful, but 034 * WITHOUT ANY WARRANTY; without even the implied warranty of 035 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 036 * Lesser General Public License for more details. <br> 037 * <br> 038 * You should have received a copy of the GNU Lesser General Public 039 * License along with this library; if not see 040 * <a href='http://www.gnu.org/licenses/'>http://www.gnu.org/licenses/</a>. 041 */ 042public class TimeChange extends RandomMove<Lecture, Placement> { 043 044 public TimeChange(DataProperties config) { 045 super(config); 046 } 047 048 @Override 049 public Neighbour<Lecture, Placement> selectNeighbour(Solution<Lecture, Placement> solution) { 050 TimetableModel model = (TimetableModel)solution.getModel(); 051 int varIdx = ToolBox.random(model.variables().size()); 052 for (int i = 0; i < model.variables().size(); i++) { 053 Lecture lecture = model.variables().get((i + varIdx) % model.variables().size()); 054 Placement old = lecture.getAssignment(); 055 if (old == null) continue; 056 List<TimeLocation> values = lecture.timeLocations(); 057 if (values.isEmpty()) continue; 058 int valIdx = ToolBox.random(values.size()); 059 for (int j = 0; j < values.size(); j++) { 060 TimeLocation time = values.get((j + valIdx) % values.size()); 061 if (time.getPreference() > 50) continue; 062 063 Placement placement = null; 064 if (lecture.getNrRooms() == 0) 065 placement = new Placement(lecture, time, (RoomLocation) null); 066 else if (lecture.getNrRooms() == 1) 067 placement = new Placement(lecture, time, old.getRoomLocation()); 068 else 069 placement = new Placement(lecture, time, old.getRoomLocations()); 070 071 if (placement.isValid() && !model.inConflict(placement)) { 072 SimpleNeighbour<Lecture, Placement> n = new SimpleNeighbour<Lecture, Placement>(lecture, placement); 073 if (!iHC || n.value() <= 0) return n; 074 } 075 } 076 } 077 return null; 078 } 079 080 081}