001package net.sf.cpsolver.coursett.criteria.additional;
002
003import java.util.Map;
004import java.util.Set;
005
006import net.sf.cpsolver.coursett.criteria.TimetablingCriterion;
007import net.sf.cpsolver.coursett.model.Lecture;
008import net.sf.cpsolver.coursett.model.Placement;
009import net.sf.cpsolver.coursett.model.RoomLocation;
010import net.sf.cpsolver.ifs.solver.Solver;
011import net.sf.cpsolver.ifs.util.DataProperties;
012
013/**
014 * Cost for using room(s) that are too big. I.e., a difference between size of the assigned room and the size of the 
015 * smallest room in which the class can be placed {@link Lecture#minRoomSize()}.
016 * <br><br>
017 * A weight for room size penalty can be set by problem property Comparator.RoomSizeWeight.
018 * <br><br>
019 * The difference function can be made polynomial by using Comparator.RoomSizeFactor parameter
020 * (defaults to 1.05). The value of this criteria is then cubed by the power of this room
021 * size factor. This is to be able to favor a room swap between two classes at the same time,
022 * in which a smaller class takes a smaller room. To do this, set Comparator.RoomSizeFactor to
023 * a number bigger than one that is close to one (e.g., 1.05).
024 *   
025 * <br>
026 * 
027 * @version CourseTT 1.2 (University Course Timetabling)<br>
028 *          Copyright (C) 2006 - 2013 Tomáš Müller<br>
029 *          <a href="mailto:muller@unitime.org">muller@unitime.org</a><br>
030 *          <a href="http://muller.unitime.org">http://muller.unitime.org</a><br>
031 * <br>
032 *          This library is free software; you can redistribute it and/or modify
033 *          it under the terms of the GNU Lesser General Public License as
034 *          published by the Free Software Foundation; either version 3 of the
035 *          License, or (at your option) any later version. <br>
036 * <br>
037 *          This library is distributed in the hope that it will be useful, but
038 *          WITHOUT ANY WARRANTY; without even the implied warranty of
039 *          MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
040 *          Lesser General Public License for more details. <br>
041 * <br>
042 *          You should have received a copy of the GNU Lesser General Public
043 *          License along with this library; if not see
044 *          <a href='http://www.gnu.org/licenses/'>http://www.gnu.org/licenses/</a>.
045 */
046public class RoomSizePenalty extends TimetablingCriterion {
047    private double iRoomSizeFactor = 1.0;
048
049    @Override
050    public boolean init(Solver<Lecture, Placement> solver) {   
051        super.init(solver);
052        iRoomSizeFactor = solver.getProperties().getPropertyDouble("Comparator.RoomSizeFactor", 1.05);
053        return true; 
054    }
055    
056    @Override
057    public double getWeightDefault(DataProperties config) {
058        return config.getPropertyDouble("Comparator.RoomSizeWeight", 0.001);
059    }
060    
061    @Override
062    public String getPlacementSelectionWeightName() {
063        return "Placement.RoomSizeWeight";
064    }
065    
066    @Override
067    public double getValue(Placement value, Set<Placement> conflicts) {
068        if (value.variable().getNrRooms() <= 0) return 0.0;
069        double size = 0;
070        if (value.getRoomLocation() != null)
071            size = value.getRoomLocation().getRoomSize();
072        else if (value.getRoomLocations() != null) {
073            for (RoomLocation room: value.getRoomLocations())
074                size += room.getRoomSize();
075            size /= value.getNrRooms();
076        }
077        double diff = size - value.variable().minRoomSize();
078        return (diff < 0 ? 0 : Math.pow(diff, iRoomSizeFactor));
079    }
080    
081    @Override
082    public void getInfo(Map<String, String> info) {
083        if (getValue() != 0.0)
084            info.put(getName(), sDoubleFormat.format(Math.pow(getValue() / getModel().nrAssignedVariables(), 1.0 / iRoomSizeFactor)));
085    }
086
087}