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