001package org.cpsolver.ifs.model;
002
003import java.util.Map;
004
005import org.cpsolver.ifs.assignment.Assignment;
006
007
008/**
009 * IFS neighbour.
010 * 
011 * @see org.cpsolver.ifs.heuristics.NeighbourSelection
012 * 
013 * @version IFS 1.3 (Iterative Forward Search)<br>
014 *          Copyright (C) 2006 - 2014 Tomáš Müller<br>
015 *          <a href="mailto:muller@unitime.org">muller@unitime.org</a><br>
016 *          <a href="http://muller.unitime.org">http://muller.unitime.org</a><br>
017 * <br>
018 *          This library is free software; you can redistribute it and/or modify
019 *          it under the terms of the GNU Lesser General Public License as
020 *          published by the Free Software Foundation; either version 3 of the
021 *          License, or (at your option) any later version. <br>
022 * <br>
023 *          This library is distributed in the hope that it will be useful, but
024 *          WITHOUT ANY WARRANTY; without even the implied warranty of
025 *          MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
026 *          Lesser General Public License for more details. <br>
027 * <br>
028 *          You should have received a copy of the GNU Lesser General Public
029 *          License along with this library; if not see
030 *          <a href='http://www.gnu.org/licenses/'>http://www.gnu.org/licenses/</a>.
031 * 
032 * @param <V> Variable
033 * @param <T> Value
034 */
035public interface Neighbour<V extends Variable<V, T>, T extends Value<V, T>> {
036    /** Perform assignment 
037     * @param assignment current assignment
038     * @param iteration current iteration
039     **/
040    public void assign(Assignment<V, T> assignment, long iteration);
041
042    /** Difference in the evaluation function, if this neighnour is assigned.
043     * @param assignment current assignment
044     * @return difference in the solution value when assigned
045     **/
046    public double value(Assignment<V, T> assignment);
047    
048    /** Return assignments to be done.
049     * @return list of assignments (including unassignments) of this neighbour
050     **/
051    public Map<V, T> assignments(); 
052}