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 * @author  Tomáš Müller
032 * @version ExamTT 1.3 (Examination Timetabling)<br>
033 *          Copyright (C) 2008 - 2014 Tomáš Müller<br>
034 *          <a href="mailto:muller@unitime.org">muller@unitime.org</a><br>
035 *          <a href="http://muller.unitime.org">http://muller.unitime.org</a><br>
036 * <br>
037 *          This library is free software; you can redistribute it and/or modify
038 *          it under the terms of the GNU Lesser General Public License as
039 *          published by the Free Software Foundation; either version 3 of the
040 *          License, or (at your option) any later version. <br>
041 * <br>
042 *          This library is distributed in the hope that it will be useful, but
043 *          WITHOUT ANY WARRANTY; without even the implied warranty of
044 *          MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
045 *          Lesser General Public License for more details. <br>
046 * <br>
047 *          You should have received a copy of the GNU Lesser General Public
048 *          License along with this library; if not see
049 *          <a href='http://www.gnu.org/licenses/'>http://www.gnu.org/licenses/</a>.
050 */
051public class StudentDistanceBackToBackConflicts extends ExamCriterion {
052    private double iBackToBackDistance = -1;
053    
054    @Override
055    public void configure(DataProperties properties) {   
056        super.configure(properties);
057        iBackToBackDistance = properties.getPropertyDouble("Exams.BackToBackDistance", iBackToBackDistance);
058    }
059    
060    @Override
061    public String getWeightName() {
062        return "Exams.DistanceBackToBackConflictWeight";
063    }
064    
065    @Override
066    public String getXmlWeightName() {
067        return "distanceBackToBackConflictWeight";
068    }
069    
070    @Override
071    public double getWeightDefault(DataProperties config) {
072        return 25.0;
073    }
074    
075    /**
076     * Back-to-back distance. Can be set by
077     * problem property Exams.BackToBackDistance, or in the input xml file,
078     * property backToBackDistance)
079     * @return back-to-back distance in meters
080     */
081    public double getBackToBackDistance() {
082        return iBackToBackDistance;
083    }
084    
085    /**
086     * Back-to-back distance. Can be set by
087     * problem property Exams.BackToBackDistance, or in the input xml file,
088     * property backToBackDistance)
089     * @param backToBackDistance back-to-back distance in meters
090     */
091    public void setBackToBackDistance(double backToBackDistance) {
092        iBackToBackDistance = backToBackDistance;
093    }
094
095    @Override
096    public void getXmlParameters(Map<String, String> params) {
097        params.put(getXmlWeightName(), String.valueOf(getWeight()));
098        params.put("backToBackDistance", String.valueOf(getBackToBackDistance()));
099    }
100    
101    @Override
102    public void setXmlParameters(Map<String, String> params) {
103        try {
104            setWeight(Double.valueOf(params.get(getXmlWeightName())));
105        } catch (NumberFormatException e) {} catch (NullPointerException e) {}
106        try {
107            setBackToBackDistance(Double.valueOf(params.get("backToBackDistance")));
108        } catch (NumberFormatException e) {} catch (NullPointerException e) {}
109    }
110    
111    @Override
112    public double getValue(Assignment<Exam, ExamPlacement> assignment, ExamPlacement value, Set<ExamPlacement> conflicts) {
113        Exam exam = value.variable();
114        if (getBackToBackDistance() < 0) return 0;
115        int penalty = 0;
116        ExamPeriod period = value.getPeriod();
117        Map<ExamStudent, Set<Exam>> prev = (period.prev() != null && period.prev().getDay() == period.getDay() ? ((ExamModel)getModel()).getStudentsOfPeriod(assignment, period.prev()) : null);
118        Map<ExamStudent, Set<Exam>> next = (period.next() != null && period.next().getDay() == period.getDay() ? ((ExamModel)getModel()).getStudentsOfPeriod(assignment, period.next()) : null);
119        for (ExamStudent s : exam.getStudents()) {
120            if (prev != null) {
121                Set<Exam> exams = prev.get(s);
122                if (exams != null)
123                    for (Exam x : exams) {
124                        if (x.equals(exam))
125                            continue;
126                        if (value.getDistanceInMeters(assignment.getValue(x)) > getBackToBackDistance())
127                            penalty++;
128                    }
129            }
130            if (next != null) {
131                Set<Exam> exams = next.get(s);
132                if (exams != null)
133                    for (Exam x : exams) {
134                        if (x.equals(exam))
135                            continue;
136                        if (value.getDistanceInMeters(assignment.getValue(x)) > getBackToBackDistance())
137                            penalty++;
138                    }
139            }
140        }
141        /*
142        for (ExamStudent s : exam.getStudents()) {
143            if (period.prev() != null) {
144                if (period.prev().getDay() == period.getDay()) {
145                    for (Exam x : s.getExams(assignment, period.prev())) {
146                        if (x.equals(exam))
147                            continue;
148                        if (value.getDistanceInMeters(assignment.getValue(x)) > getBackToBackDistance())
149                            penalty++;
150                    }
151                }
152            }
153            if (period.next() != null) {
154                if (period.next().getDay() == period.getDay()) {
155                    for (Exam x : s.getExams(assignment, period.next())) {
156                        if (x.equals(exam))
157                            continue;
158                        if (value.getDistanceInMeters(assignment.getValue(x)) > getBackToBackDistance())
159                            penalty++;
160                    }
161                }
162            }
163        }
164        */
165        return penalty;
166    }
167    
168    @Override
169    public String getName() {
170        return "Distance Back-To-Back Conflicts";
171    }
172    
173    @Override
174    public void getInfo(Assignment<Exam, ExamPlacement> assignment, Map<String, String> info) {
175        if (getBackToBackDistance() >= 0.0 && getValue(assignment) != 0.0)
176            info.put(getName(), sDoubleFormat.format(getValue(assignment)));
177    }
178    
179    @Override
180    public String toString(Assignment<Exam, ExamPlacement> assignment) {
181        return (getValue(assignment) <= 0.0 ? "" : "BTBd:" + sDoubleFormat.format(getValue(assignment)));
182    }
183
184    @Override
185    public boolean isPeriodCriterion() { return false; }
186}