001package org.cpsolver.exam.criteria;
002
003import java.util.Collection;
004import java.util.Map;
005import java.util.Set;
006
007import org.cpsolver.exam.model.Exam;
008import org.cpsolver.exam.model.ExamModel;
009import org.cpsolver.exam.model.ExamPlacement;
010import org.cpsolver.ifs.assignment.Assignment;
011import org.cpsolver.ifs.util.DataProperties;
012
013
014/**
015 * Front load penalty. I.e., large exam is discouraged to be placed on or after a
016 * certain period.
017 * <br><br>
018 * <b>largeSize</b>: An exam is considered large, if its size is greater or equal to 
019 * this number. Value -1 means all exams are small. It can be set by problem
020 * property Exams.LargeSize, or in the input xml file, property largeSize.
021 * <br><br>
022 * <b>largePeriod</b>: Period index (number of periods multiplied by this number) for front load
023 * criteria for large exams. Can be set by problem property
024 * Exams.LargePeriod, or in the input xml file, property largePeriod.
025 * <br><br>
026 * Weight of the front load criterion, i.e., a weight for assigning a large exam
027 * after large period can be set by problem property Exams.LargeWeight, or
028 * in the input xml file, property largeWeight.
029 * 
030 * <br>
031 * 
032 * @version ExamTT 1.3 (Examination Timetabling)<br>
033 *          Copyright (C) 2008 - 2014 Tomáš Müller<br>
034 *          <a href="mailto:muller@unitime.org">muller@unitime.org</a><br>
035 *          <a href="http://muller.unitime.org">http://muller.unitime.org</a><br>
036 * <br>
037 *          This library is free software; you can redistribute it and/or modify
038 *          it under the terms of the GNU Lesser General Public License as
039 *          published by the Free Software Foundation; either version 3 of the
040 *          License, or (at your option) any later version. <br>
041 * <br>
042 *          This library is distributed in the hope that it will be useful, but
043 *          WITHOUT ANY WARRANTY; without even the implied warranty of
044 *          MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
045 *          Lesser General Public License for more details. <br>
046 * <br>
047 *          You should have received a copy of the GNU Lesser General Public
048 *          License along with this library; if not see
049 *          <a href='http://www.gnu.org/licenses/'>http://www.gnu.org/licenses/</a>.
050 */
051public class LargeExamsPenalty extends ExamCriterion {
052    private int iLargeSize = -1;
053    private double iLargePeriod = 0.67;
054    
055    @Override
056    public String getWeightName() {
057        return "Exams.LargeWeight";
058    }
059    
060    @Override
061    public String getXmlWeightName() {
062        return "largeWeight";
063    }
064    
065    @Override
066    public void getXmlParameters(Map<String, String> params) {
067        params.put(getXmlWeightName(), String.valueOf(getWeight()));
068        params.put("largeSize", String.valueOf(getLargeSize()));
069        params.put("largePeriod", String.valueOf(getLargePeriod()));
070    }
071    
072    @Override
073    public void setXmlParameters(Map<String, String> params) {
074        try {
075            setWeight(Double.valueOf(params.get(getXmlWeightName())));
076        } catch (NumberFormatException e) {} catch (NullPointerException e) {}
077        try {
078            setLargeSize(Integer.valueOf(params.get("largeSize")));
079        } catch (NumberFormatException e) {} catch (NullPointerException e) {}
080        try {
081            setLargePeriod(Double.valueOf(params.get("largePeriod")));
082        } catch (NumberFormatException e) {} catch (NullPointerException e) {}
083    }
084    
085    @Override
086    public double getWeightDefault(DataProperties config) {
087        return 1.0;
088    }
089    
090    @Override
091    public void configure(DataProperties properties) {   
092        super.configure(properties);
093        iLargeSize = properties.getPropertyInt("Exams.LargeSize", iLargeSize);
094        iLargePeriod = properties.getPropertyDouble("Exams.LargePeriod", iLargePeriod);
095    }
096    
097    /**
098     * An exam is considered large, if its size is greater or equal to this
099     * large size. Value -1 means all exams are small. Can be set by problem
100     * property Exams.LargeSize, or in the input xml file, property largeSize)
101     * @return large size
102     **/
103    public int getLargeSize() {
104        return iLargeSize;
105    }
106    
107    /**
108     * An exam is considered large, if its size is greater or equal to this
109     * large size. Value -1 means all exams are small. Can be set by problem
110     * property Exams.LargeSize, or in the input xml file, property largeSize)
111     * @param largeSize large size
112     **/
113    public void setLargeSize(int largeSize) {
114        iLargeSize = largeSize;
115    }
116    
117    /**
118     * Period index (number of periods multiplied by this number) for front load
119     * criteria for large exams. Can be set by problem property
120     * Exams.LargePeriod, or in the input xml file, property largePeriod)
121     * @return large period
122     **/
123    public double getLargePeriod() {
124        return iLargePeriod;
125    }
126    
127    /**
128     * Period index (number of periods multiplied by this number) for front load
129     * criteria for large exams. Can be set by problem property
130     * Exams.LargePeriod, or in the input xml file, property largePeriod)
131     * @param largePeriod large period
132     **/
133    public void setLargePeriod(double largePeriod) {
134        iLargePeriod = largePeriod;
135    }
136
137    
138    public int getLargePeriodIndex() {
139        return (int) Math.round(((ExamModel)getModel()).getPeriods().size() * iLargePeriod);
140    }
141
142    @Override
143    public double getValue(Assignment<Exam, ExamPlacement> assignment, ExamPlacement value, Set<ExamPlacement> conflicts) {
144        Exam exam = value.variable();
145        if (getLargeSize() < 0 || exam.getSize() < getLargeSize()) return 0;
146        return (value.getPeriod().getIndex() < getLargePeriodIndex() ? 0 : 1);
147    }
148
149    @Override
150    public double[] getBounds(Assignment<Exam, ExamPlacement> assignment, Collection<Exam> variables) {
151        double[] bounds = new double[] { 0.0, 0.0 };
152        for (Exam exam : variables) {
153            if (getLargeSize() >= 0 && exam.getSize() >= getLargeSize())
154                bounds[1] += 1.0;
155        }
156        return bounds;
157    }
158
159    @Override
160    public String toString(Assignment<Exam, ExamPlacement> assignment) {
161        return (getValue(assignment) <= 0.0 ? "" : "LP:" + sDoubleFormat.format(getValue(assignment)));
162    }
163}