001package org.cpsolver.instructor.criteria;
002
003import java.util.Collection;
004import java.util.Set;
005
006import org.cpsolver.ifs.assignment.Assignment;
007import org.cpsolver.ifs.util.DataProperties;
008import org.cpsolver.instructor.model.Instructor;
009import org.cpsolver.instructor.model.TeachingAssignment;
010import org.cpsolver.instructor.model.TeachingRequest;
011
012/**
013 * Same Common Preferences. This criterion counts how well are the same common preferences that are set on a {@link TeachingRequest} met
014 * (counting {@link TeachingRequest#getSameCommonPenalty(TeachingRequest)}).
015 * 
016 * @author  Tomáš Müller
017 * @version IFS 1.3 (Instructor Sectioning)<br>
018 *          Copyright (C) 2016 Tomáš Müller<br>
019 *          <a href="mailto:muller@unitime.org">muller@unitime.org</a><br>
020 *          <a href="http://muller.unitime.org">http://muller.unitime.org</a><br>
021 * <br>
022 *          This library is free software; you can redistribute it and/or modify
023 *          it under the terms of the GNU Lesser General Public License as
024 *          published by the Free Software Foundation; either version 3 of the
025 *          License, or (at your option) any later version. <br>
026 * <br>
027 *          This library is distributed in the hope that it will be useful, but
028 *          WITHOUT ANY WARRANTY; without even the implied warranty of
029 *          MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
030 *          Lesser General Public License for more details. <br>
031 * <br>
032 *          You should have received a copy of the GNU Lesser General Public
033 *          License along with this library; if not see
034 *          <a href='http://www.gnu.org/licenses/'>http://www.gnu.org/licenses/</a>.
035 */
036public class SameCommon extends InstructorSchedulingCriterion {
037    
038    public SameCommon() {
039        setValueUpdateType(ValueUpdateType.NoUpdate);
040    }
041
042    @Override
043    public double getWeightDefault(DataProperties config) {
044        return 1000000.0;
045    }
046
047    @Override
048    public double getValue(Assignment<TeachingRequest.Variable, TeachingAssignment> assignment, TeachingAssignment value, Set<TeachingAssignment> conflicts) {
049        Instructor.Context context = value.getInstructor().getContext(assignment);
050        double penalty = 0.0;
051        int pairs = 0;
052        for (TeachingAssignment ta : context.getAssignments()) {
053            if (ta.variable().equals(value.variable()))
054                continue;
055            penalty += value.variable().getRequest().getSameCommonPenalty(ta.variable().getRequest());
056            pairs ++;
057        }
058        return (pairs == 0 ? 0.0 : penalty / pairs);
059    }
060    
061    @Override
062    public double[] getBounds(Assignment<TeachingRequest.Variable, TeachingAssignment> assignment, Collection<TeachingRequest.Variable> variables) {
063        double[] bounds = new double[] { 0.0, 0.0 };
064        for (TeachingRequest.Variable req: variables) {
065            if (!req.getRequest().isSameCommonProhibited() && !req.getRequest().isSameCommonRequired())
066                if (req.getRequest().getSameCommonPreference() < 0) {
067                    bounds[0] += req.getRequest().getSameCommonPreference();
068                } else {
069                    bounds[1] += req.getRequest().getSameCommonPreference();
070                }
071        }
072        return bounds;
073    }
074    
075    @Override
076    public double getValue(Assignment<TeachingRequest.Variable, TeachingAssignment> assignment, Collection<TeachingRequest.Variable> variables) {
077        return 0.5 * super.getValue(assignment, variables);
078    }
079
080    @Override
081    public String getAbbreviation() {
082        return "SameCommon";
083    }
084}