    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 instructor conflicts. I.e., number of cases when
    017 * an exam is attended by an instructor that attends some other exam at
    018 * the previous {@link ExamPeriod#prev()} or following
    019 * {@link ExamPeriod#next()} period. If
    020 * {@link StudentBackToBackConflicts#isDayBreakBackToBack()} is false, back-to-back conflicts
    021 * are only considered between consecutive periods that are of the same day.
    022 * <br><br>
    023 * Back-to-back instructor conflict weight can be set by problem property
    024 * Exams.InstructorBackToBackConflictWeight, or in the input xml file,
    025 * property instructorBackToBackConflictWeight.
    026 *
    027 *
    028 * <br>
    029 *
    030 * @author  Tomáš Müller
    031 * @version ExamTT 1.3 (Examination Timetabling)<br>
    032 *          Copyright (C) 2008 - 2014 Tomáš Müller<br>
    033 *          <a href="mailto:muller@unitime.org">muller@unitime.org</a><br>
    034 *          <a href="http://muller.unitime.org">http://muller.unitime.org</a><br>
    035 * <br>
    036 *          This library is free software; you can redistribute it and/or modify
    037 *          it under the terms of the GNU Lesser General Public License as
    038 *          published by the Free Software Foundation; either version 3 of the
    039 *          License, or (at your option) any later version. <br>
    040 * <br>
    041 *          This library is distributed in the hope that it will be useful, but
    042 *          WITHOUT ANY WARRANTY; without even the implied warranty of
    043 *          MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
    044 *          Lesser General Public License for more details. <br>
    045 * <br>
    046 *          You should have received a copy of the GNU Lesser General Public
    047 *          License along with this library; if not see
    048 *          <a href='http://www.gnu.org/licenses/'>http://www.gnu.org/licenses/</a>.
    049 */
    050public class InstructorBackToBackConflicts extends StudentBackToBackConflicts {
    051
    052    @Override
    053    public String getWeightName() {
    054        return "Exams.InstructorBackToBackConflictWeight";
    055    }
    056
    057    @Override
    058    public String getXmlWeightName() {
    059        return "instructorBackToBackConflictWeight";
    060    }
    061
    062    @Override
    063    public double getWeightDefault(DataProperties config) {
    064        return 10.0;
    065    }
    066
    067    @Override
    068    public double getValue(Assignment<Exam, ExamPlacement> assignment, ExamPlacement value, Set<ExamPlacement> conflicts) {
    069        Exam exam = value.variable();
    070        int penalty = 0;
    071        ExamPeriod period = value.getPeriod();
    072        Map<ExamInstructor, Set<Exam>> prev = (period.prev() != null && (isDayBreakBackToBack() || period.prev().getDay() == period.getDay()) ? ((ExamModel)getModel()).getInstructorsOfPeriod(assignment, period.prev()) : null);
    073        Map<ExamInstructor, Set<Exam>> next = (period.next() != null && (isDayBreakBackToBack() || period.next().getDay() == period.getDay()) ? ((ExamModel)getModel()).getInstructorsOfPeriod(assignment, period.next()) : null);
    074        for (ExamInstructor s : exam.getInstructors()) {
    075            if (prev != null) {
    076                Set<Exam> exams = prev.get(s);
    077                if (exams != null) {
    078                    int nrExams = exams.size() + (exams.contains(exam) ? -1 : 0);
    079                    penalty += nrExams;
    080                }
    081            }
    082            if (next != null) {
    083                Set<Exam> exams = next.get(s);
    084                if (exams != null) {
    085                    int nrExams = exams.size() + (exams.contains(exam) ? -1 : 0);
    086                    penalty += nrExams;
    087                }
    088            }
    089        }
    090        /*
    091        for (ExamInstructor s : exam.getInstructors()) {
    092            if (period.prev() != null) {
    093                if (isDayBreakBackToBack() || period.prev().getDay() == period.getDay()) {
    094                    Set<Exam> exams = s.getExams(assignment, period.prev());
    095                    int nrExams = exams.size() + (exams.contains(exam) ? -1 : 0);
    096                    penalty += nrExams;
    097                }
    098            }
    099            if (period.next() != null) {
    100                if (isDayBreakBackToBack() || period.next().getDay() == period.getDay()) {
    101                    Set<Exam> exams = s.getExams(assignment, period.next());
    102                    int nrExams = exams.size() + (exams.contains(exam) ? -1 : 0);
    103                    penalty += nrExams;
    104                }
    105            }
    106        }
    107        */
    108        return penalty;
    109    }
    110
    111    @Override
    112    public String getName() {
    113        return "Instructor Back-To-Back Conflicts";
    114    }
    115
    116    @Override
    117    public String toString(Assignment<Exam, ExamPlacement> assignment) {
    118        return "iBTB:" + sDoubleFormat.format(getValue(assignment));
    119    }
    120
    121}