001package org.cpsolver.exam.criteria;
002
003import java.util.Map;
004import java.util.Set;
005
006import org.cpsolver.exam.model.Exam;
007import org.cpsolver.exam.model.ExamPlacement;
008import org.cpsolver.exam.model.ExamRoomPlacement;
009import org.cpsolver.ifs.assignment.Assignment;
010import org.cpsolver.ifs.util.DataProperties;
011
012
013/**
014 * Room split distance penalty. I.e., average distance between two rooms of a placement.
015 * <br><br>
016 * A weight for room split penalty can be set by problem
017 * property Exams.RoomSplitWeight, or in the input xml file, property
018 * roomSplitDistanceWeight).
019 * 
020 * <br>
021 * 
022 * @author  Tomáš Müller
023 * @version ExamTT 1.3 (Examination Timetabling)<br>
024 *          Copyright (C) 2008 - 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 RoomSplitDistancePenalty  extends ExamCriterion {
043
044    @Override
045    public ValueContext createAssignmentContext(Assignment<Exam, ExamPlacement> assignment) {
046        return new RoomSplitContext(assignment);
047    }
048    
049    @Override
050    public String getWeightName() {
051        return "Exams.RoomSplitDistanceWeight";
052    }
053    
054    @Override
055    public String getXmlWeightName() {
056        return "roomSplitDistanceWeight";
057    }
058    
059    @Override
060    public double getWeightDefault(DataProperties config) {
061        return 0.01;
062    }
063    
064    @Override
065    public double getValue(Assignment<Exam, ExamPlacement> assignment, ExamPlacement value, Set<ExamPlacement> conflicts) {
066        if (value.getRoomPlacements() == null || value.getRoomPlacements().size() <= 1) return 0.0;
067        double distance = 0.0;
068        for (ExamRoomPlacement r : value.getRoomPlacements()) {
069            for (ExamRoomPlacement w : value.getRoomPlacements()) {
070                if (r.getRoom().getId() < w.getRoom().getId())
071                    distance += r.getRoom().getDistanceInMeters(w.getRoom());
072            }
073        }
074        int pairs = value.getRoomPlacements().size() * (value.getRoomPlacements().size() - 1) / 2;
075        return distance / pairs;
076    }
077    
078    @Override
079    public void getInfo(Assignment<Exam, ExamPlacement> assignment, Map<String, String> info) {
080        if (getValue(assignment) != 0.0) {
081            info.put(getName(), sDoubleFormat.format(getValue(assignment) / nrRoomSplits(assignment)) + " m");
082        }
083    }
084    
085    @Override
086    public String toString(Assignment<Exam, ExamPlacement> assignment) {
087        return "RSd:" + sDoubleFormat.format(getValue(assignment) / nrRoomSplits(assignment));
088    }
089    
090    public int nrRoomSplits(Assignment<Exam, ExamPlacement> assignment) {
091        return ((RoomSplitContext)getContext(assignment)).nrRoomSplits();
092    }
093
094    @Override
095    public boolean isPeriodCriterion() { return false; }
096    
097    protected class RoomSplitContext extends ValueContext {
098        private int iRoomSplits = 0;
099        
100        public RoomSplitContext(Assignment<Exam, ExamPlacement> assignment) {
101            super(assignment);
102            for (Exam exam: getModel().variables()) {
103                ExamPlacement placement = assignment.getValue(exam);
104                if (placement != null && placement.getRoomPlacements() != null && placement.getRoomPlacements().size() > 1)
105                    iRoomSplits ++;
106            }
107        }
108
109        @Override
110        public void assigned(Assignment<Exam, ExamPlacement> assignment, ExamPlacement value) {
111            super.assigned(assignment, value);
112            if (value.getRoomPlacements() != null && value.getRoomPlacements().size() > 1)
113                iRoomSplits ++;
114        }
115
116        @Override
117        public void unassigned(Assignment<Exam, ExamPlacement> assignment, ExamPlacement value) {
118            super.unassigned(assignment, value);
119            if (value.getRoomPlacements() != null && value.getRoomPlacements().size() > 1)
120                iRoomSplits --;
121        }
122        
123        public int nrRoomSplits() {
124            return iRoomSplits;
125        }
126    }
127}