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 * @author  Tomáš Müller
031 * @version ExamTT 1.3 (Examination Timetabling)<br>
032 *          Copyright (C) 2008 - 2014 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 DistanceToStronglyPreferredRoom extends ExamCriterion {
051    
052    @Override
053    public String getWeightName() {
054        return "Exams.DistanceToStronglyPreferredRoomWeight";
055    }
056    
057    @Override
058    public String getXmlWeightName() {
059        return "distanceToStronglyPreferredRoomWeight";
060    }
061    
062    @Override
063    public double getWeightDefault(DataProperties config) {
064        return 0.001;
065    }
066    
067    @Override
068    public double getValue(Assignment<Exam, ExamPlacement> assignment, ExamPlacement value, Set<ExamPlacement> conflicts) {
069        Average ret = new Average();
070        for (ExamRoomPlacement assigned: value.getRoomPlacements()) {
071            for (ExamRoomPlacement preferred: value.variable().getPreferredRoomPlacements())
072                ret.add(assigned.getDistanceInMeters(preferred));
073        }
074        return ret.average();
075    }
076    
077    @Override
078    public String toString(Assignment<Exam, ExamPlacement> assignment) {
079        return "@D:" + sDoubleFormat.format(getValue(assignment) / assignment.nrAssignedVariables());
080    }
081    
082    @Override
083    public double[] getBounds(Assignment<Exam, ExamPlacement> assignment) {
084        return new double[] { 0.0, 0.0 };
085    }
086    
087    @Override
088    public void getInfo(Assignment<Exam, ExamPlacement> assignment, Map<String, String> info) {
089        if (getValue(assignment) > 0.0)
090            info.put(getName(), sDoubleFormat.format(getValue(assignment) / assignment.nrAssignedVariables()) + " m");
091    }
092        
093    private static class Average {
094        double iValue = 0.0;
095        int iCount = 0;
096        
097        private void add(double value) {
098            iValue += value; iCount ++;
099        }
100        
101        public double average() {
102            return (iCount == 0 ? 0.0 : iValue / iCount);
103        }
104    }
105
106}