    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.ExamModel;
    008import net.sf.cpsolver.exam.model.ExamPeriod;
    009import net.sf.cpsolver.exam.model.ExamPlacement;
    010import net.sf.cpsolver.exam.model.ExamStudent;
    011import net.sf.cpsolver.ifs.solver.Solver;
    012import net.sf.cpsolver.ifs.util.DataProperties;
    013
    014/**
    015 * Number of back-to-back distance student conflicts. I.e., number of
    016 * cases when an exam is attended by a student that attends some other
    017 * exam at the previous {@link ExamPeriod#prev()} or following
    018 * {@link ExamPeriod#next()} period and the distance
    019 * {@link ExamPlacement#getDistanceInMeters(ExamPlacement)} between these two exams
    020 * is greater than {@link ExamModel#getBackToBackDistance()}. Distance
    021 * back-to-back conflicts are only considered between consecutive periods
    022 * that are of the same day.
    023 * <br><br>
    024 * Distance back-to-back student conflict weight can be set by problem
    025 * property Exams.DistanceBackToBackConflictWeight, or in the
    026 * input xml file, property distanceBackToBackConflictWeight.
    027 *
    028 * <br>
    029 *
    030 * @version ExamTT 1.2 (Examination Timetabling)<br>
    031 *          Copyright (C) 2008 - 2012 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 StudentDistanceBackToBackConflicts extends ExamCriterion {
    050    private double iBackToBackDistance = -1;
    051
    052    @Override
    053    public boolean init(Solver<Exam, ExamPlacement> solver) {
    054        boolean ret = super.init(solver);
    055        iBackToBackDistance = solver.getProperties().getPropertyDouble("Exams.BackToBackDistance", iBackToBackDistance);
    056        return ret;
    057    }
    058
    059    @Override
    060    public String getWeightName() {
    061        return "Exams.DistanceBackToBackConflictWeight";
    062    }
    063
    064    @Override
    065    public String getXmlWeightName() {
    066        return "distanceBackToBackConflictWeight";
    067    }
    068
    069    @Override
    070    public double getWeightDefault(DataProperties config) {
    071        return 25.0;
    072    }
    073
    074    /**
    075     * Back-to-back distance. Can be set by
    076     * problem property Exams.BackToBackDistance, or in the input xml file,
    077     * property backToBackDistance)
    078     */
    079    public double getBackToBackDistance() {
    080        return iBackToBackDistance;
    081    }
    082
    083    /**
    084     * Back-to-back distance. Can be set by
    085     * problem property Exams.BackToBackDistance, or in the input xml file,
    086     * property backToBackDistance)
    087     */
    088    public void setBackToBackDistance(double backToBackDistance) {
    089        iBackToBackDistance = backToBackDistance;
    090    }
    091
    092    @Override
    093    public void getXmlParameters(Map<String, String> params) {
    094        params.put(getXmlWeightName(), String.valueOf(getWeight()));
    095        params.put("backToBackDistance", String.valueOf(getBackToBackDistance()));
    096    }
    097
    098    @Override
    099    public void setXmlParameters(Map<String, String> params) {
    100        try {
    101            setWeight(Double.valueOf(params.get(getXmlWeightName())));
    102        } catch (NumberFormatException e) {} catch (NullPointerException e) {}
    103        try {
    104            setBackToBackDistance(Double.valueOf(params.get("backToBackDistance")));
    105        } catch (NumberFormatException e) {} catch (NullPointerException e) {}
    106    }
    107
    108    @Override
    109    public double getValue(ExamPlacement value, Set<ExamPlacement> conflicts) {
    110        Exam exam = value.variable();
    111        if (getBackToBackDistance() < 0) return 0;
    112        int penalty = 0;
    113        for (ExamStudent s : exam.getStudents()) {
    114            if (value.getPeriod().prev() != null) {
    115                if (value.getPeriod().prev().getDay() == value.getPeriod().getDay()) {
    116                    for (Exam x : s.getExams(value.getPeriod().prev())) {
    117                        if (x.equals(exam))
    118                            continue;
    119                        if (value.getDistanceInMeters(x.getAssignment()) > getBackToBackDistance())
    120                            penalty++;
    121                    }
    122                }
    123            }
    124            if (value.getPeriod().next() != null) {
    125                if (value.getPeriod().next().getDay() == value.getPeriod().getDay()) {
    126                    for (Exam x : s.getExams(value.getPeriod().next())) {
    127                        if (x.equals(exam))
    128                            continue;
    129                        if (value.getDistanceInMeters(x.getAssignment()) > getBackToBackDistance())
    130                            penalty++;
    131                    }
    132                }
    133            }
    134        }
    135        return penalty;
    136    }
    137
    138    @Override
    139    public String getName() {
    140        return "Distance Back-To-Back Conflicts";
    141    }
    142
    143    @Override
    144    public void getInfo(Map<String, String> info) {
    145        if (getBackToBackDistance() >= 0.0 && getValue() != 0.0)
    146            info.put(getName(), sDoubleFormat.format(getValue()));
    147    }
    148
    149    @Override
    150    public String toString() {
    151        return (getValue() <= 0.0 ? "" : "BTBd:" + sDoubleFormat.format(getValue()));
    152    }
    153
    154    @Override
    155    public boolean isPeriodCriterion() { return false; }
    156}