    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.ExamModel;
    008import org.cpsolver.exam.model.ExamPeriod;
    009import org.cpsolver.exam.model.ExamPlacement;
    010import org.cpsolver.exam.model.ExamStudent;
    011import org.cpsolver.ifs.assignment.Assignment;
    012import org.cpsolver.ifs.util.DataProperties;
    013
    014
    015/**
    016 * Number of back-to-back distance student conflicts. I.e., number of
    017 * cases when an exam is attended by a student that attends some other
    018 * exam at the previous {@link ExamPeriod#prev()} or following
    019 * {@link ExamPeriod#next()} period and the distance
    020 * {@link ExamPlacement#getDistanceInMeters(ExamPlacement)} between these two exams
    021 * is greater than {@link ExamModel#getBackToBackDistance()}. Distance
    022 * back-to-back conflicts are only considered between consecutive periods
    023 * that are of the same day.
    024 * <br><br>
    025 * Distance back-to-back student conflict weight can be set by problem
    026 * property Exams.DistanceBackToBackConflictWeight, or in the
    027 * input xml file, property distanceBackToBackConflictWeight.
    028 *
    029 * <br>
    030 *
    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 StudentDistanceBackToBackConflicts extends ExamCriterion {
    051    private double iBackToBackDistance = -1;
    052
    053    @Override
    054    public void configure(DataProperties properties) {
    055        super.configure(properties);
    056        iBackToBackDistance = properties.getPropertyDouble("Exams.BackToBackDistance", iBackToBackDistance);
    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     * @return back-to-back distance in meters
    079     */
    080    public double getBackToBackDistance() {
    081        return iBackToBackDistance;
    082    }
    083
    084    /**
    085     * Back-to-back distance. Can be set by
    086     * problem property Exams.BackToBackDistance, or in the input xml file,
    087     * property backToBackDistance)
    088     * @param backToBackDistance back-to-back distance in meters
    089     */
    090    public void setBackToBackDistance(double backToBackDistance) {
    091        iBackToBackDistance = backToBackDistance;
    092    }
    093
    094    @Override
    095    public void getXmlParameters(Map<String, String> params) {
    096        params.put(getXmlWeightName(), String.valueOf(getWeight()));
    097        params.put("backToBackDistance", String.valueOf(getBackToBackDistance()));
    098    }
    099
    100    @Override
    101    public void setXmlParameters(Map<String, String> params) {
    102        try {
    103            setWeight(Double.valueOf(params.get(getXmlWeightName())));
    104        } catch (NumberFormatException e) {} catch (NullPointerException e) {}
    105        try {
    106            setBackToBackDistance(Double.valueOf(params.get("backToBackDistance")));
    107        } catch (NumberFormatException e) {} catch (NullPointerException e) {}
    108    }
    109
    110    @Override
    111    public double getValue(Assignment<Exam, ExamPlacement> assignment, ExamPlacement value, Set<ExamPlacement> conflicts) {
    112        Exam exam = value.variable();
    113        if (getBackToBackDistance() < 0) return 0;
    114        int penalty = 0;
    115        ExamPeriod period = value.getPeriod();
    116        Map<ExamStudent, Set<Exam>> prev = (period.prev() != null && period.prev().getDay() == period.getDay() ? ((ExamModel)getModel()).getStudentsOfPeriod(assignment, period.prev()) : null);
    117        Map<ExamStudent, Set<Exam>> next = (period.next() != null && period.next().getDay() == period.getDay() ? ((ExamModel)getModel()).getStudentsOfPeriod(assignment, period.next()) : null);
    118        for (ExamStudent s : exam.getStudents()) {
    119            if (prev != null) {
    120                Set<Exam> exams = prev.get(s);
    121                if (exams != null)
    122                    for (Exam x : exams) {
    123                        if (x.equals(exam))
    124                            continue;
    125                        if (value.getDistanceInMeters(assignment.getValue(x)) > getBackToBackDistance())
    126                            penalty++;
    127                    }
    128            }
    129            if (next != null) {
    130                Set<Exam> exams = next.get(s);
    131                if (exams != null)
    132                    for (Exam x : exams) {
    133                        if (x.equals(exam))
    134                            continue;
    135                        if (value.getDistanceInMeters(assignment.getValue(x)) > getBackToBackDistance())
    136                            penalty++;
    137                    }
    138            }
    139        }
    140        /*
    141        for (ExamStudent s : exam.getStudents()) {
    142            if (period.prev() != null) {
    143                if (period.prev().getDay() == period.getDay()) {
    144                    for (Exam x : s.getExams(assignment, period.prev())) {
    145                        if (x.equals(exam))
    146                            continue;
    147                        if (value.getDistanceInMeters(assignment.getValue(x)) > getBackToBackDistance())
    148                            penalty++;
    149                    }
    150                }
    151            }
    152            if (period.next() != null) {
    153                if (period.next().getDay() == period.getDay()) {
    154                    for (Exam x : s.getExams(assignment, period.next())) {
    155                        if (x.equals(exam))
    156                            continue;
    157                        if (value.getDistanceInMeters(assignment.getValue(x)) > getBackToBackDistance())
    158                            penalty++;
    159                    }
    160                }
    161            }
    162        }
    163        */
    164        return penalty;
    165    }
    166
    167    @Override
    168    public String getName() {
    169        return "Distance Back-To-Back Conflicts";
    170    }
    171
    172    @Override
    173    public void getInfo(Assignment<Exam, ExamPlacement> assignment, Map<String, String> info) {
    174        if (getBackToBackDistance() >= 0.0 && getValue(assignment) != 0.0)
    175            info.put(getName(), sDoubleFormat.format(getValue(assignment)));
    176    }
    177
    178    @Override
    179    public String toString(Assignment<Exam, ExamPlacement> assignment) {
    180        return (getValue(assignment) <= 0.0 ? "" : "BTBd:" + sDoubleFormat.format(getValue(assignment)));
    181    }
    182
    183    @Override
    184    public boolean isPeriodCriterion() { return false; }
    185}