001package org.cpsolver.instructor.criteria;
002
003import java.util.Collection;
004import java.util.HashSet;
005import java.util.Set;
006
007import org.cpsolver.ifs.assignment.Assignment;
008import org.cpsolver.ifs.util.DataProperties;
009import org.cpsolver.instructor.model.Instructor;
010import org.cpsolver.instructor.model.TeachingAssignment;
011import org.cpsolver.instructor.model.TeachingRequest;
012
013/**
014 * Unused Instructor Load. If an instructor is being used (has at least one teaching assignment),
015 * this criterion can penalize the remaining (unused) load of the instructor. That is the difference
016 * between instructor maximal load and the assigned load of the instructor.
017 * 
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 UnusedInstructorLoad extends InstructorSchedulingCriterion {
038    
039    public UnusedInstructorLoad() {
040        setValueUpdateType(ValueUpdateType.NoUpdate);
041    }
042    
043    @Override
044    public double getWeightDefault(DataProperties config) {
045        return 100000.0;
046    }
047
048    @Override
049    public double getValue(Assignment<TeachingRequest.Variable, TeachingAssignment> assignment, TeachingAssignment value, Set<TeachingAssignment> conflicts) {
050        Instructor.Context cx = value.getInstructor().getContext(assignment);
051        
052        float load = cx.getLoad();
053        if (!cx.getAssignments().contains(value)) load += value.variable().getRequest().getLoad();
054        if (conflicts != null)
055            for (TeachingAssignment ta: conflicts)
056                if (ta.getInstructor().equals(value.getInstructor())) load -= ta.variable().getRequest().getLoad();
057        
058        return Math.max(0, value.getInstructor().getMaxLoad() - load);
059    }
060    
061    @Override
062    public double getValue(Assignment<TeachingRequest.Variable, TeachingAssignment> assignment, Collection<TeachingRequest.Variable> variables) {
063        double unused = 0.0;
064        Set<Instructor> instructors = new HashSet<Instructor>();
065        for (TeachingRequest.Variable req: variables) {
066            TeachingAssignment ta = assignment.getValue(req);
067            if (ta != null &&instructors.add(ta.getInstructor())) {
068                unused += ta.getInstructor().getMaxLoad() - ta.getInstructor().getContext(assignment).getLoad();
069            }
070        }
071        return unused;
072    }
073
074    @Override
075    public String getAbbreviation() {
076        return "UnusedLoad";
077    }
078}