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.ExamInstructor;
008import org.cpsolver.exam.model.ExamModel;
009import org.cpsolver.exam.model.ExamPeriod;
010import org.cpsolver.exam.model.ExamPlacement;
011import org.cpsolver.ifs.assignment.Assignment;
012import org.cpsolver.ifs.util.DataProperties;
013
014
015/**
016 * Number of back-to-back distance instructor conflicts. I.e., number of
017 * cases when an exam is attended by an instructor 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 instructor conflict weight can be set by problem
026 * property Exams.InstructorDistanceBackToBackConflictWeight, or in the
027 * input xml file, property instructorDistanceBackToBackConflictWeight.
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 InstructorDistanceBackToBackConflicts extends StudentDistanceBackToBackConflicts {
052    
053    @Override
054    public String getWeightName() {
055        return "Exams.InstructorDistanceBackToBackConflictWeight";
056    }
057    
058    @Override
059    public String getXmlWeightName() {
060        return "instructorDistanceBackToBackConflictWeight";
061    }
062
063    @Override
064    public double getWeightDefault(DataProperties config) {
065        return 25.0;
066    }
067    
068    @Override
069    public double getValue(Assignment<Exam, ExamPlacement> assignment, ExamPlacement value, Set<ExamPlacement> conflicts) {
070        Exam exam = value.variable();
071        double btbDist = getBackToBackDistance();
072        if (btbDist < 0)
073            return 0;
074        int penalty = 0;
075        ExamPeriod period = value.getPeriod();
076        Map<ExamInstructor, Set<Exam>> prev = (period.prev() != null && period.prev().getDay() == period.getDay() ? ((ExamModel)getModel()).getInstructorsOfPeriod(assignment, period.prev()) : null);
077        Map<ExamInstructor, Set<Exam>> next = (period.next() != null && period.next().getDay() == period.getDay() ? ((ExamModel)getModel()).getInstructorsOfPeriod(assignment, period.next()) : null);
078        for (ExamInstructor s : exam.getInstructors()) {
079            if (prev != null) {
080                Set<Exam> exams = prev.get(s);
081                if (exams != null)
082                    for (Exam x : exams) {
083                        if (x.equals(exam))
084                            continue;
085                        if (value.getDistanceInMeters(assignment.getValue(x)) > getBackToBackDistance())
086                            penalty++;
087                    }
088            }
089            if (next != null) {
090                Set<Exam> exams = next.get(s);
091                if (exams != null)
092                    for (Exam x : exams) {
093                        if (x.equals(exam))
094                            continue;
095                        if (value.getDistanceInMeters(assignment.getValue(x)) > getBackToBackDistance())
096                            penalty++;
097                    }
098            }
099        }
100        /*
101        for (ExamInstructor s : exam.getInstructors()) {
102            if (period.prev() != null) {
103                if (period.prev().getDay() == period.getDay()) {
104                    for (Exam x : s.getExams(assignment, period.prev())) {
105                        if (x.equals(exam))
106                            continue;
107                        if (value.getDistanceInMeters(assignment.getValue(x)) > btbDist)
108                            penalty++;
109                    }
110                }
111            }
112            if (period.next() != null) {
113                if (period.next().getDay() == period.getDay()) {
114                    for (Exam x : s.getExams(assignment, period.next())) {
115                        if (x.equals(exam))
116                            continue;
117                        if (value.getDistanceInMeters(assignment.getValue(x)) > btbDist)
118                            penalty++;
119                    }
120                }
121            }
122        }
123        */
124        return penalty;
125    }
126
127    @Override
128    public String getName() {
129        return "Instructor Distance Back-To-Back Conflicts";
130    }
131    
132    @Override
133    public String toString(Assignment<Exam, ExamPlacement> assignment) {
134        return (getValue(assignment) <= 0.0 ? "" : "iBTBd:" + sDoubleFormat.format(getValue(assignment)));
135    }
136    
137    @Override
138    public boolean isPeriodCriterion() { return false; }
139}