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.solver.Solver;
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 * @version ExamTT 1.3 (Examination Timetabling)<br>
029 *          Copyright (C) 2008 - 2014 Tomáš Müller<br>
030 *          <a href="mailto:muller@unitime.org">muller@unitime.org</a><br>
031 *          <a href="http://muller.unitime.org">http://muller.unitime.org</a><br>
032 * <br>
033 *          This library is free software; you can redistribute it and/or modify
034 *          it under the terms of the GNU Lesser General Public License as
035 *          published by the Free Software Foundation; either version 3 of the
036 *          License, or (at your option) any later version. <br>
037 * <br>
038 *          This library is distributed in the hope that it will be useful, but
039 *          WITHOUT ANY WARRANTY; without even the implied warranty of
040 *          MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
041 *          Lesser General Public License for more details. <br>
042 * <br>
043 *          You should have received a copy of the GNU Lesser General Public
044 *          License along with this library; if not see
045 *          <a href='http://www.gnu.org/licenses/'>http://www.gnu.org/licenses/</a>.
046 */
047public class DistributionPenalty extends ExamCriterion {
048    protected Integer iSoftDistributions = null;
049    
050    public DistributionPenalty() {
051        setValueUpdateType(ValueUpdateType.NoUpdate); 
052    }
053    
054    
055    @Override
056    public boolean init(Solver<Exam, ExamPlacement> solver) {
057        if (super.init(solver)) {
058            iSoftDistributions = solver.getProperties().getPropertyInteger("Exam.SoftDistributions", null);
059            if (iSoftDistributions != null) {
060                DistributionViolation dv = new DistributionViolation();
061                getModel().addCriterion(dv);
062                return dv.init(solver);
063            }
064        }
065        return true;
066    }
067    
068    @Override
069    public String getWeightName() {
070        return "Exams.DistributionWeight";
071    }
072    
073    @Override
074    public String getXmlWeightName() {
075        return "distributionWeight";
076    }
077    
078    @Override
079    public double getWeightDefault(DataProperties config) {
080        return 1.0;
081    }
082
083    @Override
084    public double getValue(Assignment<Exam, ExamPlacement> assignment, ExamPlacement value, Set<ExamPlacement> conflicts) {
085        int penalty = 0;
086        for (ExamDistributionConstraint dc : value.variable().getDistributionConstraints()) {
087            if (dc.isHard() || (iSoftDistributions != null && iSoftDistributions == dc.getWeight()))
088                continue;
089            boolean sat = dc.isSatisfied(assignment, value);
090            if (sat != dc.isSatisfied(assignment))
091                penalty += (sat ? -dc.getWeight() : dc.getWeight());
092        }
093        return penalty;
094    }
095    
096    @Override
097    public boolean isRoomCriterion() { return true; }
098    
099    /**
100     * Room related distribution penalty, i.e., sum weights of violated
101     * distribution constraints
102     */
103    @Override
104    public double getRoomValue(Assignment<Exam, ExamPlacement> assignment, ExamPlacement value) {
105        int penalty = 0;
106        for (ExamDistributionConstraint dc : value.variable().getDistributionConstraints()) {
107            if (dc.isHard() || (iSoftDistributions != null && iSoftDistributions == dc.getWeight()) || !dc.isRoomRelated())
108                continue;
109            boolean sat = dc.isSatisfied(assignment, value);
110            if (sat != dc.isSatisfied(assignment))
111                penalty += (sat ? -dc.getWeight() : dc.getWeight());
112        }
113        return penalty;
114    }
115    
116    @Override
117    public double getValue(Assignment<Exam, ExamPlacement> assignment, Collection<Exam> variables) {
118        int penalty = 0;
119        Set<ExamDistributionConstraint> added = new HashSet<ExamDistributionConstraint>();
120        for (Exam exam: variables) {
121            for (ExamDistributionConstraint dc : exam.getDistributionConstraints()) {
122                if (added.add(dc)) {
123                    if (dc.isHard() || (iSoftDistributions != null && iSoftDistributions == dc.getWeight()))
124                        continue;
125                    if (!dc.isSatisfied(assignment))
126                        penalty += dc.getWeight();
127                }
128            }
129        }
130        return penalty;
131    }
132
133    @Override
134    public boolean isPeriodCriterion() { return true; }
135    
136    @Override
137    public void inc(Assignment<Exam, ExamPlacement> assignment, double value) {
138        if (iSoftDistributions != null && iSoftDistributions == value) {
139            getModel().getCriterion(DistributionViolation.class).inc(assignment, 1.0);
140        } else if (iSoftDistributions != null && iSoftDistributions == -value) {
141            getModel().getCriterion(DistributionViolation.class).inc(assignment, -1.0);
142        } else {
143            super.inc(assignment, value);
144        }
145    }
146    
147    /**
148     * Period related distribution penalty, i.e., sum weights of violated
149     * distribution constraints
150     */
151    @Override
152    public double getPeriodValue(Assignment<Exam, ExamPlacement> assignment, ExamPlacement value) {
153        int penalty = 0;
154        for (ExamDistributionConstraint dc : value.variable().getDistributionConstraints()) {
155            if (dc.isHard() || (iSoftDistributions != null && iSoftDistributions == dc.getWeight()) || !dc.isPeriodRelated())
156                continue;
157            boolean sat = dc.isSatisfied(assignment, value);
158            if (sat != dc.isSatisfied(assignment))
159                penalty += (sat ? -dc.getWeight() : dc.getWeight());
160        }
161        return penalty;
162    }
163    
164    @Override
165    protected double[] computeBounds(Assignment<Exam, ExamPlacement> assignment) {
166        double[] bounds = new double[] { 0.0, 0.0 };
167        for (ExamDistributionConstraint dc : ((ExamModel)getModel()).getDistributionConstraints()) {
168            if (dc.isHard() || (iSoftDistributions != null && iSoftDistributions == dc.getWeight()))
169                continue;
170            bounds[1] += dc.getWeight();
171        }
172        return bounds;
173    }
174
175    @Override
176    public String toString(Assignment<Exam, ExamPlacement> assignment) {
177        return (getValue(assignment) <= 0.0 ? "" : "DP:" + sDoubleFormat.format(getValue(assignment)));
178    }
179}