001package org.cpsolver.exam.criteria.additional;
002
003import java.util.Map;
004import java.util.Set;
005
006import org.cpsolver.exam.criteria.ExamCriterion;
007import org.cpsolver.exam.model.Exam;
008import org.cpsolver.exam.model.ExamPlacement;
009import org.cpsolver.exam.model.ExamRoomPlacement;
010import org.cpsolver.ifs.assignment.Assignment;
011import org.cpsolver.ifs.util.DataProperties;
012
013
014/**
015 * Experimental criterion measuring average distance (in meters) to the
016 * strongly preferred room (or rooms) of the examination. The idea is to
017 * prefer rooms that are close to the strongly preference room (if there is
018 * a strongly preferred room but it is not available).
019 * <br><br>
020 * A weight of the average distance between the assigned room(s) and the 
021 * strongly preferred room or rooms can be set using
022 * Exams.DistanceToStronglyPreferredRoomWeight property. 
023 * <br><br>
024 * To enable this criterion add this class name to Exams.AdditionalCriteria
025 * parameter. For instance:<br>
026 * Exams.AdditionalCriteria=org.cpsolver.exam.criteria.additional.DistanceToStronglyPreferredRoom
027 * 
028 * <br>
029 * 
030 * @version ExamTT 1.3 (Examination Timetabling)<br>
031 *          Copyright (C) 2008 - 2014 Tomáš Müller<br>
032 *          <a href="mailto:muller@unitime.org">muller@unitime.org</a><br>
033 *          <a href="http://muller.unitime.org">http://muller.unitime.org</a><br>
034 * <br>
035 *          This library is free software; you can redistribute it and/or modify
036 *          it under the terms of the GNU Lesser General Public License as
037 *          published by the Free Software Foundation; either version 3 of the
038 *          License, or (at your option) any later version. <br>
039 * <br>
040 *          This library is distributed in the hope that it will be useful, but
041 *          WITHOUT ANY WARRANTY; without even the implied warranty of
042 *          MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
043 *          Lesser General Public License for more details. <br>
044 * <br>
045 *          You should have received a copy of the GNU Lesser General Public
046 *          License along with this library; if not see
047 *          <a href='http://www.gnu.org/licenses/'>http://www.gnu.org/licenses/</a>.
048 */
049public class DistanceToStronglyPreferredRoom extends ExamCriterion {
050    
051    @Override
052    public String getWeightName() {
053        return "Exams.DistanceToStronglyPreferredRoomWeight";
054    }
055    
056    @Override
057    public String getXmlWeightName() {
058        return "distanceToStronglyPreferredRoomWeight";
059    }
060    
061    @Override
062    public double getWeightDefault(DataProperties config) {
063        return 0.001;
064    }
065    
066    @Override
067    public double getValue(Assignment<Exam, ExamPlacement> assignment, ExamPlacement value, Set<ExamPlacement> conflicts) {
068        Average ret = new Average();
069        for (ExamRoomPlacement assigned: value.getRoomPlacements()) {
070            for (ExamRoomPlacement preferred: value.variable().getPreferredRoomPlacements())
071                ret.add(assigned.getDistanceInMeters(preferred));
072        }
073        return ret.average();
074    }
075    
076    @Override
077    public String toString(Assignment<Exam, ExamPlacement> assignment) {
078        return "@D:" + sDoubleFormat.format(getValue(assignment) / assignment.nrAssignedVariables());
079    }
080    
081    @Override
082    public double[] getBounds(Assignment<Exam, ExamPlacement> assignment) {
083        return new double[] { 0.0, 0.0 };
084    }
085    
086    @Override
087    public void getInfo(Assignment<Exam, ExamPlacement> assignment, Map<String, String> info) {
088        if (getValue(assignment) > 0.0)
089            info.put(getName(), sDoubleFormat.format(getValue(assignment) / assignment.nrAssignedVariables()) + " m");
090    }
091        
092    private static class Average {
093        double iValue = 0.0;
094        int iCount = 0;
095        
096        private void add(double value) {
097            iValue += value; iCount ++;
098        }
099        
100        public double average() {
101            return (iCount == 0 ? 0.0 : iValue / iCount);
102        }
103    }
104
105}