001package org.cpsolver.exam.criteria.additional;
002
003import java.util.Collection;
004import java.util.HashSet;
005import java.util.Set;
006
007import org.cpsolver.exam.criteria.ExamCriterion;
008import org.cpsolver.exam.model.Exam;
009import org.cpsolver.exam.model.ExamDistributionConstraint;
010import org.cpsolver.exam.model.ExamModel;
011import org.cpsolver.exam.model.ExamPlacement;
012import org.cpsolver.ifs.assignment.Assignment;
013
014
015/**
016 * Experimental criterion counting violations of hard distribution constraints.
017 * <br><br>
018 * To enable breaking of hard distribution constraints, set parameter Exam.SoftDistributions to
019 * a weight that should be inferred by a hard distribution constraint being broken.
020 * 
021 * <br>
022 * 
023 * @version ExamTT 1.3 (Examination Timetabling)<br>
024 *          Copyright (C) 2008 - 2014 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 DistributionViolation extends ExamCriterion {
043    
044    public DistributionViolation() {
045        super();
046        setValueUpdateType(ValueUpdateType.NoUpdate);
047    }
048
049    @Override
050    public String getWeightName() {
051        return "Exam.SoftDistributions";
052    }
053    
054    @Override
055    public String getXmlWeightName() {
056        return "softDistributions";
057    }
058
059    @Override
060    public double getValue(Assignment<Exam, ExamPlacement> assignment, ExamPlacement value, Set<ExamPlacement> conflicts) {
061        int penalty = 0;
062        ExamPlacement original = assignment.getValue(value.variable());
063        for (ExamDistributionConstraint dc : value.variable().getDistributionConstraints()) {
064            if (dc.isHard() || getWeight() != dc.getWeight())
065                continue;
066            penalty += dc.countViolations(assignment, value);
067            if (original != null) penalty -= dc.countViolations(assignment, original);
068        }
069        return penalty;
070    }
071    
072    @Override
073    protected double[] computeBounds(Assignment<Exam, ExamPlacement> assignment) {
074        double[] bounds = new double[] { 0.0, 0.0 };
075        for (ExamDistributionConstraint dc : ((ExamModel)getModel()).getDistributionConstraints()) {
076            if (!dc.isHard() && getWeight() == dc.getWeight())
077                bounds[1] += dc.variables().size() * (dc.variables().size() - 1) / 2;
078        }
079        return bounds;
080    }
081    
082    @Override
083    public boolean isRoomCriterion() { return true; }
084    
085    @Override
086    public double getRoomValue(Assignment<Exam, ExamPlacement> assignment, ExamPlacement value) {
087        int penalty = 0;
088        ExamPlacement original = assignment.getValue(value.variable());
089        for (ExamDistributionConstraint dc : value.variable().getDistributionConstraints()) {
090            if (dc.isHard() || getWeight() != dc.getWeight() || !dc.isRoomRelated())
091                continue;
092            penalty += dc.countViolations(assignment, value);
093            if (original != null) penalty -= dc.countViolations(assignment, original);
094        }
095        return penalty;
096    }
097
098    @Override
099    public boolean isPeriodCriterion() { return true; }
100    
101    @Override
102    public double getPeriodValue(Assignment<Exam, ExamPlacement> assignment, ExamPlacement value) {
103        int penalty = 0;
104        ExamPlacement original = assignment.getValue(value.variable());
105        for (ExamDistributionConstraint dc : value.variable().getDistributionConstraints()) {
106            if (dc.isHard() || getWeight() != dc.getWeight() || !dc.isPeriodRelated())
107                continue;
108            penalty += dc.countViolations(assignment, value);
109            if (original != null) penalty -= dc.countViolations(assignment, original);
110        }
111        return penalty;
112    }
113    
114    @Override
115    public double getValue(Assignment<Exam, ExamPlacement> assignment, Collection<Exam> variables) {
116        int penalty = 0;
117        Set<ExamDistributionConstraint> added = new HashSet<ExamDistributionConstraint>();
118        for (Exam exam: variables) {
119            for (ExamDistributionConstraint dc : exam.getDistributionConstraints()) {
120                if (added.add(dc)) {
121                    if (dc.isHard() || getWeight() != dc.getWeight())
122                        continue;
123                    penalty += dc.countViolations(assignment);
124                }
125            }
126        }
127        return penalty;
128    }
129
130    @Override
131    public String toString(Assignment<Exam, ExamPlacement> assignment) {
132        return (getValue(assignment) <= 0.0 ? "" : "!D:" + sDoubleFormat.format(getValue(assignment)));
133    }
134}