001package org.cpsolver.exam.criteria;
002
003import java.util.Collection;
004import java.util.Map;
005import java.util.Set;
006
007import org.cpsolver.exam.model.Exam;
008import org.cpsolver.exam.model.ExamModel;
009import org.cpsolver.exam.model.ExamPeriod;
010import org.cpsolver.exam.model.ExamPlacement;
011import org.cpsolver.exam.model.ExamStudent;
012import org.cpsolver.ifs.assignment.Assignment;
013import org.cpsolver.ifs.util.DataProperties;
014
015
016/**
017 * Number of direct student conflicts. I.e., number of cases when an
018 * exam is attended by a student that attends some other exam at the
019 * same period.
020 * <br><br>
021 * Direct student conflict weight can be set by problem property
022 * Exams.DirectConflictWeight, or in the input xml file, property
023 * directConflictWeight.
024 * 
025 * <br>
026 * 
027 * @author  Tomáš Müller
028 * @version ExamTT 1.3 (Examination Timetabling)<br>
029 *          Copyright (C) 2008 - 2014 Tomáš Müller<br>
030 *          <a href="mailto:muller@unitime.org">muller@unitime.org</a><br>
031 *          <a href="http://muller.unitime.org">http://muller.unitime.org</a><br>
032 * <br>
033 *          This library is free software; you can redistribute it and/or modify
034 *          it under the terms of the GNU Lesser General Public License as
035 *          published by the Free Software Foundation; either version 3 of the
036 *          License, or (at your option) any later version. <br>
037 * <br>
038 *          This library is distributed in the hope that it will be useful, but
039 *          WITHOUT ANY WARRANTY; without even the implied warranty of
040 *          MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
041 *          Lesser General Public License for more details. <br>
042 * <br>
043 *          You should have received a copy of the GNU Lesser General Public
044 *          License along with this library; if not see
045 *          <a href='http://www.gnu.org/licenses/'>http://www.gnu.org/licenses/</a>.
046 */
047public class StudentDirectConflicts extends ExamCriterion {
048    
049    @Override
050    public String getWeightName() {
051        return "Exams.DirectConflictWeight";
052    }
053    
054    @Override
055    public String getXmlWeightName() {
056        return "directConflictWeight";
057    }
058
059    @Override
060    public double getWeightDefault(DataProperties config) {
061        return 1000.0;
062    }
063    
064    @Override
065    public double getValue(Assignment<Exam, ExamPlacement> assignment, ExamPlacement value, Set<ExamPlacement> conflicts) {
066        Exam exam = value.variable();
067        int penalty = 0;
068        ExamPeriod period = value.getPeriod();
069        ExamModel m = (ExamModel)getModel();
070        Map<ExamStudent, Set<Exam>> students = m.getStudentsOfPeriod(assignment, period);
071        for (ExamStudent s : exam.getStudents()) {
072            Set<Exam> exams = students.get(s);
073            if (exams == null) continue;
074            int nrExams = exams.size() + (exams.contains(exam) ? 0 : 1);
075            if (nrExams > 1)
076                penalty++;
077        }
078        if (m.isCheckForPeriodOverlaps()) {
079            for (ExamPeriod p: m.getPeriods()) {
080                if (period.hasIntersection(p)) {
081                    Map<ExamStudent, Set<Exam>> others = m.getStudentsOfPeriod(assignment, p);
082                    s: for (ExamStudent s : exam.getStudents()) {
083                        Set<Exam> exams = students.get(s);
084                        if (exams == null || exams.size() + (exams.contains(exam) ? 0 : 1) <= 1) {
085                            Set<Exam> other = others.get(s);
086                            if (other != null && !other.isEmpty())
087                                for (Exam x: other) {
088                                    if (period.hasIntersection(exam, x, p)) {
089                                        penalty ++; continue s;
090                                    }
091                                }
092                        }
093                    }
094                }
095            }
096        }
097        /*
098        for (ExamStudent s : exam.getStudents()) {
099            Set<Exam> exams = s.getExams(assignment, period);
100            if (exams.isEmpty()) continue;
101            int nrExams = exams.size() + (exams.contains(exam) ? 0 : 1);
102            if (nrExams > 1)
103                penalty++;
104        }
105        */
106        return penalty;
107    }
108
109    @Override
110    public String getName() {
111        return "Direct Conflicts";
112    }
113    
114    @Override
115    public void getInfo(Assignment<Exam, ExamPlacement> assignment, Map<String, String> info) {
116        StudentNotAvailableConflicts na = (StudentNotAvailableConflicts)getModel().getCriterion(StudentNotAvailableConflicts.class);
117        if (getValue(assignment) != 0.0 || (na != null && na.getValue(assignment) != 0.0))
118            info.put(getName(), sDoubleFormat.format(getValue(assignment) + (na == null ? 0.0 : na.getValue(assignment))) +
119                    (na == null || na.getValue(assignment) == 0.0 ? "" : " (" + sDoubleFormat.format(na.getValue(assignment)) + " N/A)"));
120    }
121    
122    @Override
123    public double getValue(Assignment<Exam, ExamPlacement> assignment, Collection<Exam> variables) {
124        int ret = 0;
125        ExamModel m = (ExamModel)getModel();
126        for (ExamPeriod p: m.getPeriods()) {
127            Map<ExamStudent, Set<Exam>> students = ((ExamModel)getModel()).getStudentsOfPeriod(assignment, p);
128            for (Set<Exam> exams: students.values()) {
129                int nrExams = exams.size();
130                if (nrExams > 1)
131                    ret += nrExams - 1;
132            }
133        }
134        if (m.isCheckForPeriodOverlaps()) {
135            for (ExamPeriod p: m.getPeriods()) {
136                for (ExamPeriod q: m.getPeriods()) {
137                    if (p.getIndex() < q.getIndex() && p.hasIntersection(q)) {
138                        Map<ExamStudent, Set<Exam>> s1 = m.getStudentsOfPeriod(assignment, p);
139                        Map<ExamStudent, Set<Exam>> s2 = m.getStudentsOfPeriod(assignment, q);
140                        for (Map.Entry<ExamStudent, Set<Exam>> e: s1.entrySet()) {
141                            ExamStudent s = e.getKey();
142                            if (!e.getValue().isEmpty()) {
143                                Set<Exam> x = s2.get(s);
144                                if (x != null && x.isEmpty()) {
145                                    x1: for (Exam x1: e.getValue()) {
146                                        for (Exam x2: x) {
147                                            if (p.hasIntersection(x1, x2, q)) {
148                                                ret += 1; break x1;
149                                            }
150                                        }
151                                    }
152                                }
153                            }
154                        }
155                    }
156                }
157            }
158        }
159        return ret;
160    }
161
162    @Override
163    public String toString(Assignment<Exam, ExamPlacement> assignment) {
164        return "DC:" + sDoubleFormat.format(getValue(assignment));
165    }
166}