001package org.cpsolver.exam.neighbours;
002
003import java.text.DecimalFormat;
004
005import org.apache.log4j.Logger;
006import org.cpsolver.exam.model.Exam;
007import org.cpsolver.exam.model.ExamModel;
008import org.cpsolver.exam.model.ExamPlacement;
009import org.cpsolver.ifs.assignment.Assignment;
010import org.cpsolver.ifs.model.SimpleNeighbour;
011
012
013/**
014 * Extension of {@link SimpleNeighbour}. The only difference is that the value (
015 * {@link SimpleNeighbour#value(Assignment)}) is decreased by 1000 if the selected
016 * variable has no current assignment. <br>
017 * <br>
018 * 
019 * @version ExamTT 1.3 (Examination Timetabling)<br>
020 *          Copyright (C) 2008 - 2014 Tomáš Müller<br>
021 *          <a href="mailto:muller@unitime.org">muller@unitime.org</a><br>
022 *          <a href="http://muller.unitime.org">http://muller.unitime.org</a><br>
023 * <br>
024 *          This library is free software; you can redistribute it and/or modify
025 *          it under the terms of the GNU Lesser General Public License as
026 *          published by the Free Software Foundation; either version 3 of the
027 *          License, or (at your option) any later version. <br>
028 * <br>
029 *          This library is distributed in the hope that it will be useful, but
030 *          WITHOUT ANY WARRANTY; without even the implied warranty of
031 *          MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
032 *          Lesser General Public License for more details. <br>
033 * <br>
034 *          You should have received a copy of the GNU Lesser General Public
035 *          License along with this library; if not see
036 *          <a href='http://www.gnu.org/licenses/'>http://www.gnu.org/licenses/</a>.
037 */
038public class ExamSimpleNeighbour extends SimpleNeighbour<Exam, ExamPlacement> {
039    private static Logger sLog = Logger.getLogger(ExamSimpleNeighbour.class);
040    private static boolean sCheck = false;
041    private double iValue = 0;
042    private double iDx;
043
044    public ExamSimpleNeighbour(Assignment<Exam, ExamPlacement> assignment, ExamPlacement placement) {
045        super(placement.variable(), placement);
046        iValue = placement.toDouble(assignment);
047        ExamPlacement current = assignment.getValue(placement.variable()); 
048        if (current != null)
049            iValue -= current.toDouble(assignment);
050        else
051            iValue -= 1000;
052        if (sCheck) {
053            iDx = placement.toDouble(assignment);
054            if (current != null)
055                iDx -= current.toDouble(assignment);
056        }
057    }
058
059    @Override
060    public void assign(Assignment<Exam, ExamPlacement> assignment, long iteration) {
061        if (sCheck) {
062            double beforeVal = getVariable().getModel().getTotalValue(assignment);
063            double[] beforeValM = ((ExamModel) getVariable().getModel()).getTotalMultiValue(assignment);
064            String n = toString();
065            assignment.assign(iteration, getValue());
066            double afterVal = getVariable().getModel().getTotalValue(assignment);
067            double[] afterValM = ((ExamModel) getVariable().getModel()).getTotalMultiValue(assignment);
068            /*
069             * int before = getVariable().getModel().nrUnassignedVariables();
070             * int after = getVariable().getModel().nrUnassignedVariables(); if
071             * (after>before) {
072             * sLog.error("-- assignment mischmatch (delta:"+(after
073             * -before)+")"); sLog.error("  -- neighbour: "+n); }
074             */
075            if (Math.abs(afterVal - beforeVal - iDx) >= 0.0000001) {
076                sLog.error("-- value mischmatch (delta:" + (afterVal - beforeVal) + ", value:" + iDx + ")");
077                sLog.error("  -- neighbour: " + n);
078                sLog.error("  -- solution:  " + toString(afterValM, beforeValM));
079            }
080        } else {
081            assignment.assign(iteration, getValue());
082        }
083    }
084
085    protected static String toString(double[] x) {
086        DecimalFormat df = new DecimalFormat("0.00");
087        StringBuffer s = new StringBuffer();
088        for (int i = 0; i < x.length; i++) {
089            if (i > 0)
090                s.append(",");
091            s.append(df.format(x[i]));
092        }
093        return "[" + s.toString() + "]";
094    }
095
096    protected static String toString(double[] x, double[] y) {
097        DecimalFormat df = new DecimalFormat("0.00");
098        StringBuffer s = new StringBuffer();
099        for (int i = 0; i < x.length; i++) {
100            if (i > 0)
101                s.append(",");
102            s.append(df.format(x[i] - y[i]));
103        }
104        return "[" + s.toString() + "]";
105    }
106
107    @Override
108    public String toString() {
109        return getVariable() + " := " + getValue().toString() + " / " + " (value:" + value(null) + ")";
110    }
111
112    @Override
113    public double value(Assignment<Exam, ExamPlacement> assignment) {
114        return iValue;
115    }
116}