001    package net.sf.cpsolver.exam.criteria.additional;
002    
003    import java.util.Map;
004    import java.util.Set;
005    
006    import net.sf.cpsolver.exam.criteria.ExamCriterion;
007    import net.sf.cpsolver.exam.model.ExamPlacement;
008    import net.sf.cpsolver.exam.model.ExamRoomPlacement;
009    import net.sf.cpsolver.ifs.util.DataProperties;
010    
011    /**
012     * Experimental criterion measuring average distance (in meters) to the
013     * strongly preferred room (or rooms) of the examination. The idea is to
014     * prefer rooms that are close to the strongly preference room (if there is
015     * a strongly preferred room but it is not available).
016     * <br><br>
017     * A weight of the average distance between the assigned room(s) and the 
018     * strongly preferred room or rooms can be set using
019     * Exams.DistanceToStronglyPreferredRoomWeight property. 
020     * <br><br>
021     * To enable this criterion add this class name to Exams.AdditionalCriteria
022     * parameter. For instance:<br>
023     * Exams.AdditionalCriteria=net.sf.cpsolver.exam.criteria.additional.DistanceToStronglyPreferredRoom
024     * 
025     * <br>
026     * 
027     * @version ExamTT 1.2 (Examination Timetabling)<br>
028     *          Copyright (C) 2008 - 2012 Tomas Muller<br>
029     *          <a href="mailto:muller@unitime.org">muller@unitime.org</a><br>
030     *          <a href="http://muller.unitime.org">http://muller.unitime.org</a><br>
031     * <br>
032     *          This library is free software; you can redistribute it and/or modify
033     *          it under the terms of the GNU Lesser General Public License as
034     *          published by the Free Software Foundation; either version 3 of the
035     *          License, or (at your option) any later version. <br>
036     * <br>
037     *          This library is distributed in the hope that it will be useful, but
038     *          WITHOUT ANY WARRANTY; without even the implied warranty of
039     *          MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
040     *          Lesser General Public License for more details. <br>
041     * <br>
042     *          You should have received a copy of the GNU Lesser General Public
043     *          License along with this library; if not see
044     *          <a href='http://www.gnu.org/licenses/'>http://www.gnu.org/licenses/</a>.
045     */
046    public class DistanceToStronglyPreferredRoom extends ExamCriterion {
047        
048        @Override
049        public String getWeightName() {
050            return "Exams.DistanceToStronglyPreferredRoomWeight";
051        }
052        
053        @Override
054        public String getXmlWeightName() {
055            return "distanceToStronglyPreferredRoomWeight";
056        }
057        
058        @Override
059        public double getWeightDefault(DataProperties config) {
060            return 0.001;
061        }
062        
063        @Override
064        public double getValue(ExamPlacement value, Set<ExamPlacement> conflicts) {
065            Average ret = new Average();
066            for (ExamRoomPlacement assigned: value.getRoomPlacements()) {
067                for (ExamRoomPlacement preferred: value.variable().getRoomPlacements()) {
068                    if (preferred.getPenalty() < -2) // strongly preferred
069                        ret.add(assigned.getDistanceInMeters(preferred));
070                }
071            }
072            return ret.average();
073        }
074        
075        @Override
076        public String toString() {
077            return "@D:" + sDoubleFormat.format(getValue() / getModel().assignedVariables().size());
078        }
079        
080        @Override
081        public double[] getBounds() {
082            return new double[] { 0.0, 0.0 };
083        }
084        
085        @Override
086        public void getInfo(Map<String, String> info) {
087            if (getValue() > 0.0)
088                info.put(getName(), sDoubleFormat.format(getValue() / getModel().assignedVariables().size()) + " m");
089        }
090            
091        private static class Average {
092            double iValue = 0.0;
093            int iCount = 0;
094            
095            private void add(double value) {
096                iValue += value; iCount ++;
097            }
098            
099            public double average() {
100                return (iCount == 0 ? 0.0 : iValue / iCount);
101            }
102        }
103    
104    }