001package net.sf.cpsolver.exam.criteria.additional;
002
003import java.util.Map;
004import java.util.Set;
005
006import net.sf.cpsolver.exam.criteria.ExamCriterion;
007import net.sf.cpsolver.exam.model.ExamPlacement;
008import net.sf.cpsolver.exam.model.ExamRoomPlacement;
009import net.sf.cpsolver.ifs.util.DataProperties;
010
011/**
012 * Experimental criterion measuring average distance (in meters) to the
013 * strongly preferred room (or rooms) of the examination. The idea is to
014 * prefer rooms that are close to the strongly preference room (if there is
015 * a strongly preferred room but it is not available).
016 * <br><br>
017 * A weight of the average distance between the assigned room(s) and the 
018 * strongly preferred room or rooms can be set using
019 * Exams.DistanceToStronglyPreferredRoomWeight property. 
020 * <br><br>
021 * To enable this criterion add this class name to Exams.AdditionalCriteria
022 * parameter. For instance:<br>
023 * Exams.AdditionalCriteria=net.sf.cpsolver.exam.criteria.additional.DistanceToStronglyPreferredRoom
024 * 
025 * <br>
026 * 
027 * @version ExamTT 1.2 (Examination Timetabling)<br>
028 *          Copyright (C) 2008 - 2012 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 DistanceToStronglyPreferredRoom extends ExamCriterion {
047    
048    @Override
049    public String getWeightName() {
050        return "Exams.DistanceToStronglyPreferredRoomWeight";
051    }
052    
053    @Override
054    public String getXmlWeightName() {
055        return "distanceToStronglyPreferredRoomWeight";
056    }
057    
058    @Override
059    public double getWeightDefault(DataProperties config) {
060        return 0.001;
061    }
062    
063    @Override
064    public double getValue(ExamPlacement value, Set<ExamPlacement> conflicts) {
065        Average ret = new Average();
066        for (ExamRoomPlacement assigned: value.getRoomPlacements()) {
067            for (ExamRoomPlacement preferred: value.variable().getRoomPlacements()) {
068                if (preferred.getPenalty() < -2) // strongly preferred
069                    ret.add(assigned.getDistanceInMeters(preferred));
070            }
071        }
072        return ret.average();
073    }
074    
075    @Override
076    public String toString() {
077        return "@D:" + sDoubleFormat.format(getValue() / getModel().assignedVariables().size());
078    }
079    
080    @Override
081    public double[] getBounds() {
082        return new double[] { 0.0, 0.0 };
083    }
084    
085    @Override
086    public void getInfo(Map<String, String> info) {
087        if (getValue() > 0.0)
088            info.put(getName(), sDoubleFormat.format(getValue() / getModel().assignedVariables().size()) + " m");
089    }
090        
091    private static class Average {
092        double iValue = 0.0;
093        int iCount = 0;
094        
095        private void add(double value) {
096            iValue += value; iCount ++;
097        }
098        
099        public double average() {
100            return (iCount == 0 ? 0.0 : iValue / iCount);
101        }
102    }
103
104}