001package net.sf.cpsolver.coursett.criteria.additional;
002
003import java.util.Collection;
004import java.util.Map;
005
006import net.sf.cpsolver.coursett.constraint.JenrlConstraint;
007import net.sf.cpsolver.coursett.model.Lecture;
008import net.sf.cpsolver.coursett.model.Student;
009import net.sf.cpsolver.ifs.util.DataProperties;
010
011/**
012 * Instructor student conflicts. This criterion penalizes cases when an instructor (of a class) is attending some 
013 * other class as a student and there is a conflict between the two classes. Also, there is no alternative for the
014 * student class (the conflict cannot be sectioned away).
015 * <br>
016 * To enable instructor student conflicts, set solver parameter Global.LoadStudentInstructorConflicts to true. Also
017 * student course requests should be used in this case (to be able to match an instructor external id to a student 
018 * external id).
019 * <br>
020 * Hard instructor student conflicts are weighted by Comparator.InstructorHardStudentConflictWeight.
021 * <br>
022 * 
023 * @version CourseTT 1.2 (University Course Timetabling)<br>
024 *          Copyright (C) 2006 - 2011 Tomáš Müller<br>
025 *          <a href="mailto:muller@unitime.org">muller@unitime.org</a><br>
026 *          <a href="http://muller.unitime.org">http://muller.unitime.org</a><br>
027 * <br>
028 *          This library is free software; you can redistribute it and/or modify
029 *          it under the terms of the GNU Lesser General Public License as
030 *          published by the Free Software Foundation; either version 3 of the
031 *          License, or (at your option) any later version. <br>
032 * <br>
033 *          This library is distributed in the hope that it will be useful, but
034 *          WITHOUT ANY WARRANTY; without even the implied warranty of
035 *          MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
036 *          Lesser General Public License for more details. <br>
037 * <br>
038 *          You should have received a copy of the GNU Lesser General Public
039 *          License along with this library; if not see
040 *          <a href='http://www.gnu.org/licenses/'>http://www.gnu.org/licenses/</a>.
041 */
042public class InstructorStudentHardConflict extends InstructorStudentConflict {
043    
044    @Override
045    public boolean isApplicable(Lecture l1, Lecture l2) {
046        return super.isApplicable(l1, l2) && oneInstructorOtherHard(l1, l2);
047    }
048    
049    /**
050     * One of the lectures is hard, there is a joint enrollment constraint between them, and 
051     * there is at least one student that is instructor for one lecture and the other lecture
052     * is singleton.
053     */
054    public static boolean oneInstructorOtherHard(Lecture l1, Lecture l2) {
055        if (!hard(l1, l2)) return false;
056        JenrlConstraint jenrl = l1.jenrlConstraint(l2);
057        if (jenrl == null) return false;
058        for (Student student: jenrl.getInstructors()) {
059            if ((l1.isSingleSection() || student.getInstructor().variables().contains(jenrl.second())) &&
060                (l2.isSingleSection() || student.getInstructor().variables().contains(jenrl.first())))
061                return true;
062        }
063        return false;
064    }
065
066    @Override
067    public double getWeightDefault(DataProperties config) {
068        return config.getPropertyDouble("Comparator.InstructorHardStudentConflictWeight", 10.0 * config.getPropertyDouble("Comparator.HardStudentConflictWeight", 5.0));
069    }
070    
071    @Override
072    public String getPlacementSelectionWeightName() {
073        return "Placement.NrInstructorHardStudConfsWeight";
074    }
075    
076    @Override
077    public void getInfo(Map<String, String> info) {
078    }
079    
080    @Override
081    public void getInfo(Map<String, String> info, Collection<Lecture> variables) {
082    }
083
084}