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}