    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.InstructorSchedulingModel;
    010import org.cpsolver.instructor.model.TeachingAssignment;
    011import org.cpsolver.instructor.model.TeachingRequest;
    012
    013/**
    014 * Back to Back. This criterion counts how well are the back-to-back preferences that are set on an {@link Instructor} met
    015 * (counting {@link Instructor#countBackToBacks(Assignment, TeachingAssignment, double, double)}).
    016 *
    017 * @author  Tomáš Müller
    018 * @version IFS 1.3 (Instructor Sectioning)<br>
    019 *          Copyright (C) 2016 Tomáš Müller<br>
    020 *          <a href="mailto:muller@unitime.org">muller@unitime.org</a><br>
    021 *          <a href="http://muller.unitime.org">http://muller.unitime.org</a><br>
    022 * <br>
    023 *          This library is free software; you can redistribute it and/or modify
    024 *          it under the terms of the GNU Lesser General Public License as
    025 *          published by the Free Software Foundation; either version 3 of the
    026 *          License, or (at your option) any later version. <br>
    027 * <br>
    028 *          This library is distributed in the hope that it will be useful, but
    029 *          WITHOUT ANY WARRANTY; without even the implied warranty of
    030 *          MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
    031 *          Lesser General Public License for more details. <br>
    032 * <br>
    033 *          You should have received a copy of the GNU Lesser General Public
    034 *          License along with this library; if not see
    035 *          <a href='http://www.gnu.org/licenses/'>http://www.gnu.org/licenses/</a>.
    036 */
    037public class BackToBack extends InstructorSchedulingCriterion {
    038    private double iDiffRoomWeight = 0.8, iDiffTypeWeight = 0.5;
    039
    040    public BackToBack() {
    041        setValueUpdateType(ValueUpdateType.NoUpdate);
    042    }
    043
    044    @Override
    045    public void configure(DataProperties properties) {
    046        super.configure(properties);
    047        iDiffRoomWeight = properties.getPropertyDouble("BackToBack.DifferentRoomWeight", 0.8);
    048        iDiffTypeWeight = properties.getPropertyDouble("BackToBack.DifferentTypeWeight", 0.5);
    049    }
    050
    051    @Override
    052    public double getWeightDefault(DataProperties config) {
    053        return 1.0;
    054    }
    055
    056    /**
    057     * Different room weight
    058     * @return penalty for teaching two back-to-back that are in different rooms
    059     */
    060    public double getDifferentRoomWeight() { return iDiffRoomWeight; }
    061
    062    /**
    063     * Different instructional type weight
    064     * @return penalty for teaching two back-to-back that are of different instructional type
    065     */
    066    public double getDifferentTypeWeight() { return iDiffTypeWeight; }
    067
    068    @Override
    069    public double getValue(Assignment<TeachingRequest.Variable, TeachingAssignment> assignment, TeachingAssignment value, Set<TeachingAssignment> conflicts) {
    070        return value.getInstructor().countBackToBacks(assignment, value, iDiffRoomWeight, iDiffTypeWeight);
    071    }
    072
    073    @Override
    074    protected double[] computeBounds(Assignment<TeachingRequest.Variable, TeachingAssignment> assignment) {
    075        double[] bounds = new double[] { 0.0, 0.0 };
    076        for (Instructor instructor: ((InstructorSchedulingModel)getModel()).getInstructors()) {
    077            bounds[1] += Math.abs(instructor.getBackToBackPreference());
    078        }
    079        return bounds;
    080    }
    081
    082    @Override
    083    public double[] getBounds(Assignment<TeachingRequest.Variable, TeachingAssignment> assignment, Collection<TeachingRequest.Variable> variables) {
    084        double[] bounds = new double[] { 0.0, 0.0 };
    085        for (Instructor instructor: getInstructors(assignment, variables)) {
    086            bounds[1] += Math.abs(instructor.getBackToBackPreference());
    087        }
    088        return bounds;
    089    }
    090
    091    @Override
    092    public double getValue(Assignment<TeachingRequest.Variable, TeachingAssignment> assignment, Collection<TeachingRequest.Variable> variables) {
    093        double value = 0.0;
    094        for (Instructor instructor: getAssignedInstructors(assignment, variables))
    095            value += instructor.getContext(assignment).countBackToBackPreference(iDiffRoomWeight, iDiffTypeWeight);
    096        return value;
    097    }
    098
    099    @Override
    100    public String getAbbreviation() {
    101        return "Back2Back";
    102    }
    103}