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 * @author  Tomáš Müller
024 * @version ExamTT 1.3 (Examination Timetabling)<br>
025 *          Copyright (C) 2008 - 2014 Tomáš Müller<br>
026 *          <a href="mailto:muller@unitime.org">muller@unitime.org</a><br>
027 *          <a href="http://muller.unitime.org">http://muller.unitime.org</a><br>
028 * <br>
029 *          This library is free software; you can redistribute it and/or modify
030 *          it under the terms of the GNU Lesser General Public License as
031 *          published by the Free Software Foundation; either version 3 of the
032 *          License, or (at your option) any later version. <br>
033 * <br>
034 *          This library is distributed in the hope that it will be useful, but
035 *          WITHOUT ANY WARRANTY; without even the implied warranty of
036 *          MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
037 *          Lesser General Public License for more details. <br>
038 * <br>
039 *          You should have received a copy of the GNU Lesser General Public
040 *          License along with this library; if not see
041 *          <a href='http://www.gnu.org/licenses/'>http://www.gnu.org/licenses/</a>.
042 */
043public class DistributionViolation extends ExamCriterion {
044    
045    public DistributionViolation() {
046        super();
047        setValueUpdateType(ValueUpdateType.NoUpdate);
048    }
049
050    @Override
051    public String getWeightName() {
052        return "Exam.SoftDistributions";
053    }
054    
055    @Override
056    public String getXmlWeightName() {
057        return "softDistributions";
058    }
059
060    @Override
061    public double getValue(Assignment<Exam, ExamPlacement> assignment, ExamPlacement value, Set<ExamPlacement> conflicts) {
062        int penalty = 0;
063        ExamPlacement original = assignment.getValue(value.variable());
064        for (ExamDistributionConstraint dc : value.variable().getDistributionConstraints()) {
065            if (dc.isHard() || getWeight() != dc.getWeight())
066                continue;
067            penalty += dc.countViolations(assignment, value);
068            if (original != null) penalty -= dc.countViolations(assignment, original);
069        }
070        return penalty;
071    }
072    
073    @Override
074    protected double[] computeBounds(Assignment<Exam, ExamPlacement> assignment) {
075        double[] bounds = new double[] { 0.0, 0.0 };
076        for (ExamDistributionConstraint dc : ((ExamModel)getModel()).getDistributionConstraints()) {
077            if (!dc.isHard() && getWeight() == dc.getWeight())
078                bounds[1] += dc.variables().size() * (dc.variables().size() - 1) / 2;
079        }
080        return bounds;
081    }
082    
083    @Override
084    public boolean isRoomCriterion() { return true; }
085    
086    @Override
087    public double getRoomValue(Assignment<Exam, ExamPlacement> assignment, ExamPlacement value) {
088        int penalty = 0;
089        ExamPlacement original = assignment.getValue(value.variable());
090        for (ExamDistributionConstraint dc : value.variable().getDistributionConstraints()) {
091            if (dc.isHard() || getWeight() != dc.getWeight() || !dc.isRoomRelated())
092                continue;
093            penalty += dc.countViolations(assignment, value);
094            if (original != null) penalty -= dc.countViolations(assignment, original);
095        }
096        return penalty;
097    }
098
099    @Override
100    public boolean isPeriodCriterion() { return true; }
101    
102    @Override
103    public double getPeriodValue(Assignment<Exam, ExamPlacement> assignment, ExamPlacement value) {
104        int penalty = 0;
105        ExamPlacement original = assignment.getValue(value.variable());
106        for (ExamDistributionConstraint dc : value.variable().getDistributionConstraints()) {
107            if (dc.isHard() || getWeight() != dc.getWeight() || !dc.isPeriodRelated())
108                continue;
109            penalty += dc.countViolations(assignment, value);
110            if (original != null) penalty -= dc.countViolations(assignment, original);
111        }
112        return penalty;
113    }
114    
115    @Override
116    public double getValue(Assignment<Exam, ExamPlacement> assignment, Collection<Exam> variables) {
117        int penalty = 0;
118        Set<ExamDistributionConstraint> added = new HashSet<ExamDistributionConstraint>();
119        for (Exam exam: variables) {
120            for (ExamDistributionConstraint dc : exam.getDistributionConstraints()) {
121                if (added.add(dc)) {
122                    if (dc.isHard() || getWeight() != dc.getWeight())
123                        continue;
124                    penalty += dc.countViolations(assignment);
125                }
126            }
127        }
128        return penalty;
129    }
130
131    @Override
132    public String toString(Assignment<Exam, ExamPlacement> assignment) {
133        return (getValue(assignment) <= 0.0 ? "" : "!D:" + sDoubleFormat.format(getValue(assignment)));
134    }
135}