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