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 * @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 BackToBack extends InstructorSchedulingCriterion {
037    private double iDiffRoomWeight = 0.8, iDiffTypeWeight = 0.5;
038
039    public BackToBack() {
040        setValueUpdateType(ValueUpdateType.NoUpdate);
041    }
042    
043    @Override
044    public void configure(DataProperties properties) {   
045        super.configure(properties);
046        iDiffRoomWeight = properties.getPropertyDouble("BackToBack.DifferentRoomWeight", 0.8);
047        iDiffTypeWeight = properties.getPropertyDouble("BackToBack.DifferentTypeWeight", 0.5);
048    }
049
050    @Override
051    public double getWeightDefault(DataProperties config) {
052        return 1.0;
053    }
054    
055    /**
056     * Different room weight
057     * @return penalty for teaching two back-to-back that are in different rooms
058     */
059    public double getDifferentRoomWeight() { return iDiffRoomWeight; }
060
061    /**
062     * Different instructional type weight
063     * @return penalty for teaching two back-to-back that are of different instructional type
064     */
065    public double getDifferentTypeWeight() { return iDiffTypeWeight; }
066
067    @Override
068    public double getValue(Assignment<TeachingRequest.Variable, TeachingAssignment> assignment, TeachingAssignment value, Set<TeachingAssignment> conflicts) {
069        return value.getInstructor().countBackToBacks(assignment, value, iDiffRoomWeight, iDiffTypeWeight);
070    }
071    
072    @Override
073    protected double[] computeBounds(Assignment<TeachingRequest.Variable, TeachingAssignment> assignment) {
074        double[] bounds = new double[] { 0.0, 0.0 };
075        for (Instructor instructor: ((InstructorSchedulingModel)getModel()).getInstructors()) {
076            bounds[1] += Math.abs(instructor.getBackToBackPreference());
077        }
078        return bounds;
079    }
080    
081    @Override
082    public double[] getBounds(Assignment<TeachingRequest.Variable, TeachingAssignment> assignment, Collection<TeachingRequest.Variable> variables) {
083        double[] bounds = new double[] { 0.0, 0.0 };
084        for (Instructor instructor: getInstructors(assignment, variables)) {
085            bounds[1] += Math.abs(instructor.getBackToBackPreference());
086        }
087        return bounds;
088    }
089
090    @Override
091    public double getValue(Assignment<TeachingRequest.Variable, TeachingAssignment> assignment, Collection<TeachingRequest.Variable> variables) {
092        double value = 0.0;
093        for (Instructor instructor: getAssignedInstructors(assignment, variables))
094            value += instructor.getContext(assignment).countBackToBackPreference(iDiffRoomWeight, iDiffTypeWeight);
095        return value;
096    }
097
098    @Override
099    public String getAbbreviation() {
100        return "Back2Back";
101    }
102}