001package org.cpsolver.exam.criteria;
002
003import java.util.Collection;
004import java.util.HashSet;
005import java.util.Set;
006
007import org.cpsolver.exam.criteria.additional.DistributionViolation;
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;
013import org.cpsolver.ifs.model.Model;
014import org.cpsolver.ifs.util.DataProperties;
015
016
017/**
018 * Distribution penalty. I.e., sum weights of violated distribution
019 * constraints.
020 * <br><br>
021 * A weight of violated distribution soft constraints (see
022 * {@link ExamDistributionConstraint}) can be set by problem property
023 * Exams.RoomDistributionWeight, or in the input xml file, property
024 * roomDistributionWeight.
025 * 
026 * <br>
027 * 
028 * @author  Tomáš Müller
029 * @version ExamTT 1.3 (Examination Timetabling)<br>
030 *          Copyright (C) 2008 - 2014 Tomáš Müller<br>
031 *          <a href="mailto:muller@unitime.org">muller@unitime.org</a><br>
032 *          <a href="http://muller.unitime.org">http://muller.unitime.org</a><br>
033 * <br>
034 *          This library is free software; you can redistribute it and/or modify
035 *          it under the terms of the GNU Lesser General Public License as
036 *          published by the Free Software Foundation; either version 3 of the
037 *          License, or (at your option) any later version. <br>
038 * <br>
039 *          This library is distributed in the hope that it will be useful, but
040 *          WITHOUT ANY WARRANTY; without even the implied warranty of
041 *          MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
042 *          Lesser General Public License for more details. <br>
043 * <br>
044 *          You should have received a copy of the GNU Lesser General Public
045 *          License along with this library; if not see
046 *          <a href='http://www.gnu.org/licenses/'>http://www.gnu.org/licenses/</a>.
047 */
048public class DistributionPenalty extends ExamCriterion {
049    protected Integer iSoftDistributions = null;
050    
051    public DistributionPenalty() {
052        setValueUpdateType(ValueUpdateType.NoUpdate); 
053    }
054    
055    @Override
056    public void setModel(Model<Exam, ExamPlacement> model) {
057        super.setModel(model);
058        iSoftDistributions = ((ExamModel)model).getProperties().getPropertyInteger("Exam.SoftDistributions", null);
059        if (iSoftDistributions != null && model.getCriterion(DistributionViolation.class) == null) { 
060            DistributionViolation dv = new DistributionViolation();
061            model.addCriterion(dv);
062        }
063    }
064    
065    @Override
066    public String getWeightName() {
067        return "Exams.DistributionWeight";
068    }
069    
070    @Override
071    public String getXmlWeightName() {
072        return "distributionWeight";
073    }
074    
075    @Override
076    public double getWeightDefault(DataProperties config) {
077        return 1.0;
078    }
079
080    @Override
081    public double getValue(Assignment<Exam, ExamPlacement> assignment, ExamPlacement value, Set<ExamPlacement> conflicts) {
082        int penalty = 0;
083        ExamPlacement original = assignment.getValue(value.variable());
084        for (ExamDistributionConstraint dc : value.variable().getDistributionConstraints()) {
085            if (dc.isHard() || (iSoftDistributions != null && iSoftDistributions == dc.getWeight()))
086                continue;
087            penalty += dc.countViolations(assignment, value) * dc.getWeight();
088            if (original != null) penalty -= dc.countViolations(assignment, original) * dc.getWeight();
089        }
090        return penalty;
091    }
092    
093    @Override
094    public boolean isRoomCriterion() { return true; }
095    
096    /**
097     * Room related distribution penalty, i.e., sum weights of violated
098     * distribution constraints
099     */
100    @Override
101    public double getRoomValue(Assignment<Exam, ExamPlacement> assignment, ExamPlacement value) {
102        int penalty = 0;
103        ExamPlacement original = assignment.getValue(value.variable());
104        for (ExamDistributionConstraint dc : value.variable().getDistributionConstraints()) {
105            if (dc.isHard() || (iSoftDistributions != null && iSoftDistributions == dc.getWeight()) || !dc.isRoomRelated())
106                continue;
107            penalty += dc.countViolations(assignment, value) * dc.getWeight();
108            if (original != null) penalty -= dc.countViolations(assignment, original) * dc.getWeight();
109        }
110        return penalty;
111    }
112    
113    @Override
114    public double getValue(Assignment<Exam, ExamPlacement> assignment, Collection<Exam> variables) {
115        int penalty = 0;
116        Set<ExamDistributionConstraint> added = new HashSet<ExamDistributionConstraint>();
117        for (Exam exam: variables) {
118            for (ExamDistributionConstraint dc : exam.getDistributionConstraints()) {
119                if (added.add(dc)) {
120                    if (dc.isHard() || (iSoftDistributions != null && iSoftDistributions == dc.getWeight()))
121                        continue;
122                    penalty += dc.countViolations(assignment) * dc.getWeight();
123                }
124            }
125        }
126        return penalty;
127    }
128
129    @Override
130    public boolean isPeriodCriterion() { return true; }
131    
132    public void inc(Assignment<Exam, ExamPlacement> assignment, double value, ExamDistributionConstraint dc) {
133        if (iSoftDistributions != null && iSoftDistributions == dc.getWeight()) {
134            getModel().getCriterion(DistributionViolation.class).inc(assignment, value / dc.getWeight());
135        } else {
136            super.inc(assignment, value);
137        }
138    }
139    
140    /**
141     * Period related distribution penalty, i.e., sum weights of violated
142     * distribution constraints
143     */
144    @Override
145    public double getPeriodValue(Assignment<Exam, ExamPlacement> assignment, ExamPlacement value) {
146        int penalty = 0;
147        ExamPlacement original = assignment.getValue(value.variable());
148        for (ExamDistributionConstraint dc : value.variable().getDistributionConstraints()) {
149            if (dc.isHard() || (iSoftDistributions != null && iSoftDistributions == dc.getWeight()) || !dc.isPeriodRelated())
150                continue;
151            penalty += dc.countViolations(assignment, value) * dc.getWeight();
152            if (original != null) penalty -= dc.countViolations(assignment, original) * dc.getWeight();
153        }
154        return penalty;
155    }
156    
157    @Override
158    protected double[] computeBounds(Assignment<Exam, ExamPlacement> assignment) {
159        double[] bounds = new double[] { 0.0, 0.0 };
160        for (ExamDistributionConstraint dc : ((ExamModel)getModel()).getDistributionConstraints()) {
161            if (dc.isHard() || (iSoftDistributions != null && iSoftDistributions == dc.getWeight()))
162                continue;
163            bounds[1] += dc.getWeight() * dc.variables().size() * (dc.variables().size() - 1) / 2;
164        }
165        return bounds;
166    }
167
168    @Override
169    public String toString(Assignment<Exam, ExamPlacement> assignment) {
170        return (getValue(assignment) <= 0.0 ? "" : "DP:" + sDoubleFormat.format(getValue(assignment)));
171    }
172}