    001package net.sf.cpsolver.exam.criteria;
    002
    003import java.util.Set;
    004
    005import net.sf.cpsolver.exam.model.Exam;
    006import net.sf.cpsolver.exam.model.ExamInstructor;
    007import net.sf.cpsolver.exam.model.ExamPeriod;
    008import net.sf.cpsolver.exam.model.ExamPlacement;
    009import net.sf.cpsolver.ifs.util.DataProperties;
    010
    011/**
    012 * Number of back-to-back instructor conflicts. I.e., number of cases when
    013 * an exam is attended by an instructor that attends some other exam at
    014 * the previous {@link ExamPeriod#prev()} or following
    015 * {@link ExamPeriod#next()} period. If
    016 * {@link StudentBackToBackConflicts#isDayBreakBackToBack()} is false, back-to-back conflicts
    017 * are only considered between consecutive periods that are of the same day.
    018 * <br><br>
    019 * Back-to-back instructor conflict weight can be set by problem property
    020 * Exams.InstructorBackToBackConflictWeight, or in the input xml file,
    021 * property instructorBackToBackConflictWeight.
    022 *
    023 *
    024 * <br>
    025 *
    026 * @version ExamTT 1.2 (Examination Timetabling)<br>
    027 *          Copyright (C) 2008 - 2012 Tomáš Müller<br>
    028 *          <a href="mailto:muller@unitime.org">muller@unitime.org</a><br>
    029 *          <a href="http://muller.unitime.org">http://muller.unitime.org</a><br>
    030 * <br>
    031 *          This library is free software; you can redistribute it and/or modify
    032 *          it under the terms of the GNU Lesser General Public License as
    033 *          published by the Free Software Foundation; either version 3 of the
    034 *          License, or (at your option) any later version. <br>
    035 * <br>
    036 *          This library is distributed in the hope that it will be useful, but
    037 *          WITHOUT ANY WARRANTY; without even the implied warranty of
    038 *          MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
    039 *          Lesser General Public License for more details. <br>
    040 * <br>
    041 *          You should have received a copy of the GNU Lesser General Public
    042 *          License along with this library; if not see
    043 *          <a href='http://www.gnu.org/licenses/'>http://www.gnu.org/licenses/</a>.
    044 */
    045public class InstructorBackToBackConflicts extends StudentBackToBackConflicts {
    046
    047    @Override
    048    public String getWeightName() {
    049        return "Exams.InstructorBackToBackConflictWeight";
    050    }
    051
    052    @Override
    053    public String getXmlWeightName() {
    054        return "instructorBackToBackConflictWeight";
    055    }
    056
    057    @Override
    058    public double getWeightDefault(DataProperties config) {
    059        return 10.0;
    060    }
    061
    062    @Override
    063    public double getValue(ExamPlacement value, Set<ExamPlacement> conflicts) {
    064        Exam exam = value.variable();
    065        int penalty = 0;
    066        for (ExamInstructor s : exam.getInstructors()) {
    067            if (value.getPeriod().prev() != null) {
    068                if (isDayBreakBackToBack() || value.getPeriod().prev().getDay() == value.getPeriod().getDay()) {
    069                    Set<Exam> exams = s.getExams(value.getPeriod().prev());
    070                    int nrExams = exams.size() + (exams.contains(exam) ? -1 : 0);
    071                    penalty += nrExams;
    072                }
    073            }
    074            if (value.getPeriod().next() != null) {
    075                if (isDayBreakBackToBack() || value.getPeriod().next().getDay() == value.getPeriod().getDay()) {
    076                    Set<Exam> exams = s.getExams(value.getPeriod().next());
    077                    int nrExams = exams.size() + (exams.contains(exam) ? -1 : 0);
    078                    penalty += nrExams;
    079                }
    080            }
    081        }
    082        return penalty;
    083    }
    084
    085    @Override
    086    public String getName() {
    087        return "Instructor Back-To-Back Conflicts";
    088    }
    089
    090    @Override
    091    public String toString() {
    092        return "iBTB:" + sDoubleFormat.format(getValue());
    093    }
    094
    095}