001package org.cpsolver.coursett.criteria;
002
003import java.util.Collection;
004import java.util.HashSet;
005import java.util.Set;
006
007import org.cpsolver.coursett.constraint.DepartmentSpreadConstraint;
008import org.cpsolver.coursett.model.Lecture;
009import org.cpsolver.coursett.model.Placement;
010import org.cpsolver.ifs.assignment.Assignment;
011import org.cpsolver.ifs.util.DataProperties;
012
013
014/**
015 * Department balancing penalty. This criterion tries to balance classes of each
016 * department evenly. This means that for instance each department gets a fair
017 * amount of unpopular times like early morning or late afternoon. This criterion
018 * is counted by {@link DepartmentSpreadConstraint}. 
019 * <br>
020 * 
021 * @author  Tomáš Müller
022 * @version CourseTT 1.3 (University Course Timetabling)<br>
023 *          Copyright (C) 2006 - 2014 Tomáš Müller<br>
024 *          <a href="mailto:muller@unitime.org">muller@unitime.org</a><br>
025 *          <a href="http://muller.unitime.org">http://muller.unitime.org</a><br>
026 * <br>
027 *          This library is free software; you can redistribute it and/or modify
028 *          it under the terms of the GNU Lesser General Public License as
029 *          published by the Free Software Foundation; either version 3 of the
030 *          License, or (at your option) any later version. <br>
031 * <br>
032 *          This library is distributed in the hope that it will be useful, but
033 *          WITHOUT ANY WARRANTY; without even the implied warranty of
034 *          MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
035 *          Lesser General Public License for more details. <br>
036 * <br>
037 *          You should have received a copy of the GNU Lesser General Public
038 *          License along with this library; if not see
039 *          <a href='http://www.gnu.org/licenses/'>http://www.gnu.org/licenses/</a>.
040 */
041public class DepartmentBalancingPenalty extends SameSubpartBalancingPenalty {
042
043    @Override
044    public double getWeightDefault(DataProperties config) {
045        return 12.0 * config.getPropertyDouble("Comparator.DeptSpreadPenaltyWeight", 1.0);
046    }
047    
048    @Override
049    public String getPlacementSelectionWeightName() {
050        return "Placement.DeptSpreadPenaltyWeight";
051    }
052
053    @Override
054    public double getValue(Assignment<Lecture, Placement> assignment, Placement value, Set<Placement> conflicts) {
055        return (value.variable().getDeptSpreadConstraint() == null ? 0.0 : value.variable().getDeptSpreadConstraint().getPenalty(assignment, value)) / 12.0;
056    }
057    
058    @Override
059    public double getValue(Assignment<Lecture, Placement> assignment, Collection<Lecture> variables) {
060        double ret = 0;
061        Set<DepartmentSpreadConstraint> constraints = new HashSet<DepartmentSpreadConstraint>();
062        for (Lecture lect: variables)
063            if (lect.getDeptSpreadConstraint() != null && constraints.add(lect.getDeptSpreadConstraint()))
064                ret += lect.getDeptSpreadConstraint().getPenalty(assignment);
065        return ret / 12.0;
066    }
067}