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}