001package net.sf.cpsolver.coursett.criteria;
002
003import java.util.Collection;
004import java.util.HashSet;
005import java.util.Set;
006
007import net.sf.cpsolver.coursett.constraint.DepartmentSpreadConstraint;
008import net.sf.cpsolver.coursett.model.Lecture;
009import net.sf.cpsolver.coursett.model.Placement;
010import net.sf.cpsolver.ifs.util.DataProperties;
011
012/**
013 * Department balancing penalty. This criterion tries to balance classes of each
014 * department evenly. This means that for instance each department gets a fair
015 * amount of unpopular times like early morning or late afternoon. This criterion
016 * is counted by {@link DepartmentSpreadConstraint}. 
017 * <br>
018 * 
019 * @version CourseTT 1.2 (University Course Timetabling)<br>
020 *          Copyright (C) 2006 - 2011 Tomáš Müller<br>
021 *          <a href="mailto:muller@unitime.org">muller@unitime.org</a><br>
022 *          <a href="http://muller.unitime.org">http://muller.unitime.org</a><br>
023 * <br>
024 *          This library is free software; you can redistribute it and/or modify
025 *          it under the terms of the GNU Lesser General Public License as
026 *          published by the Free Software Foundation; either version 3 of the
027 *          License, or (at your option) any later version. <br>
028 * <br>
029 *          This library is distributed in the hope that it will be useful, but
030 *          WITHOUT ANY WARRANTY; without even the implied warranty of
031 *          MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
032 *          Lesser General Public License for more details. <br>
033 * <br>
034 *          You should have received a copy of the GNU Lesser General Public
035 *          License along with this library; if not see
036 *          <a href='http://www.gnu.org/licenses/'>http://www.gnu.org/licenses/</a>.
037 */
038public class DepartmentBalancingPenalty extends SameSubpartBalancingPenalty {
039
040    @Override
041    public double getWeightDefault(DataProperties config) {
042        return 12.0 * config.getPropertyDouble("Comparator.DeptSpreadPenaltyWeight", 1.0);
043    }
044    
045    @Override
046    public String getPlacementSelectionWeightName() {
047        return "Placement.DeptSpreadPenaltyWeight";
048    }
049
050    @Override
051    public double getValue(Placement value, Set<Placement> conflicts) {
052        return (value.variable().getDeptSpreadConstraint() == null ? 0.0 : value.variable().getDeptSpreadConstraint().getPenalty(value)) / 12.0;
053    }
054    
055    @Override
056    public double getValue(Collection<Lecture> variables) {
057        double ret = 0;
058        Set<DepartmentSpreadConstraint> constraints = new HashSet<DepartmentSpreadConstraint>();
059        for (Lecture lect: variables)
060            if (lect.getDeptSpreadConstraint() != null && constraints.add(lect.getDeptSpreadConstraint()))
061                ret += lect.getDeptSpreadConstraint().getPenalty();
062        return ret / 12.0;
063    }
064}