001package net.sf.cpsolver.exam.criteria;
002
003import java.util.Map;
004import java.util.Set;
005
006import net.sf.cpsolver.exam.model.Exam;
007import net.sf.cpsolver.exam.model.ExamPlacement;
008import net.sf.cpsolver.exam.model.ExamRoom;
009import net.sf.cpsolver.exam.model.ExamRoomPlacement;
010import net.sf.cpsolver.ifs.solver.Solver;
011import net.sf.cpsolver.ifs.util.DataProperties;
012
013/**
014 * 
015 * Cost for using room(s) that are too big. I.e., a difference between total room size
016 * (computed using either {@link ExamRoom#getSize()} or {@link ExamRoom#getAltSize()} based
017 * on {@link Exam#hasAltSeating()}) and the number of students {@link Exam#getSize()}.
018 * <br><br>
019 * A weight for room size penalty can be set by problem
020 * property Exams.RoomSizeWeight, or in the input xml file, property
021 * roomSizeWeight).
022 * <br><br>
023 * The difference function can be made polynomial by using Exams.RoomSizeFactor parameter
024 * (defaults to 1.0). The value of this criteria is then cubed by the power of this room
025 * size factor. This is to be able to favor a room swap between two exams at the same period,
026 * in which a smaller exam takes a smaller room. To do this, set Exams.RoomSizeFactor to
027 * a number bigger than one that is close to one (e.g., 1.05).
028 * 
029 * <br>
030 * 
031 * @version ExamTT 1.2 (Examination Timetabling)<br>
032 *          Copyright (C) 2008 - 2012 Tomáš Müller<br>
033 *          <a href="mailto:muller@unitime.org">muller@unitime.org</a><br>
034 *          <a href="http://muller.unitime.org">http://muller.unitime.org</a><br>
035 * <br>
036 *          This library is free software; you can redistribute it and/or modify
037 *          it under the terms of the GNU Lesser General Public License as
038 *          published by the Free Software Foundation; either version 3 of the
039 *          License, or (at your option) any later version. <br>
040 * <br>
041 *          This library is distributed in the hope that it will be useful, but
042 *          WITHOUT ANY WARRANTY; without even the implied warranty of
043 *          MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
044 *          Lesser General Public License for more details. <br>
045 * <br>
046 *          You should have received a copy of the GNU Lesser General Public
047 *          License along with this library; if not see
048 *          <a href='http://www.gnu.org/licenses/'>http://www.gnu.org/licenses/</a>.
049 */
050public class RoomSizePenalty extends ExamCriterion {
051    private double iRoomSizeFactor = 1.0;
052    
053    @Override
054    public boolean init(Solver<Exam, ExamPlacement> solver) {
055        iRoomSizeFactor = solver.getProperties().getPropertyDouble("Exams.RoomSizeFactor", 1.0);
056        return super.init(solver);
057    }
058    
059    @Override
060    public String getWeightName() {
061        return "Exams.RoomSizeWeight";
062    }
063    
064    @Override
065    public String getXmlWeightName() {
066        return "roomSizeWeight";
067    }
068    
069    @Override
070    public double getWeightDefault(DataProperties config) {
071        return 0.0001;
072    }
073    
074    @Override
075    public void getXmlParameters(Map<String, String> params) {
076        params.put(getXmlWeightName(), String.valueOf(getWeight()));
077        params.put("roomSizeFactor", String.valueOf(iRoomSizeFactor));
078    }
079    
080    @Override
081    public void setXmlParameters(Map<String, String> params) {
082        try {
083            setWeight(Double.valueOf(params.get(getXmlWeightName())));
084        } catch (NumberFormatException e) {} catch (NullPointerException e) {}
085        try {
086            iRoomSizeFactor = Double.valueOf(params.get("roomSizeFactor"));
087        } catch (NumberFormatException e) {} catch (NullPointerException e) {}
088    }
089    
090    @Override
091    public double getValue(ExamPlacement value, Set<ExamPlacement> conflicts) {
092        Exam exam = value.variable();
093        int size = 0;
094        if (value.getRoomPlacements() != null)
095            for (ExamRoomPlacement r : value.getRoomPlacements()) {
096                size += r.getSize(exam.hasAltSeating());
097            }
098        int diff = size - exam.getSize();
099        return (diff < 0 ? 0 : Math.pow(diff, iRoomSizeFactor));
100    }
101    
102    @Override
103    public void getInfo(Map<String, String> info) {
104        if (getValue() != 0.0) {
105            info.put(getName(), sDoubleFormat.format(getValue() / getModel().nrAssignedVariables()));
106        }
107    }
108
109    @Override
110    public String toString() {
111        return "RSz:" + sDoubleFormat.format(getValue() / getModel().nrAssignedVariables());
112    }
113
114    @Override
115    public boolean isPeriodCriterion() { return false; }
116}