001    package net.sf.cpsolver.coursett.criteria;
002    
003    import java.util.Collection;
004    import java.util.HashSet;
005    import java.util.Set;
006    
007    import net.sf.cpsolver.coursett.constraint.DepartmentSpreadConstraint;
008    import net.sf.cpsolver.coursett.model.Lecture;
009    import net.sf.cpsolver.coursett.model.Placement;
010    import 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 Tomas Muller<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     */
038    public 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    }