001package org.cpsolver.ifs.heuristics;
002
003import org.cpsolver.ifs.model.Neighbour;
004import org.cpsolver.ifs.model.Value;
005import org.cpsolver.ifs.model.Variable;
006import org.cpsolver.ifs.solution.Solution;
007import org.cpsolver.ifs.solver.Solver;
008
009/**
010 * Neighbour selection criterion. <br>
011 * <br>
012 * In each iteration of the solver, a neighbour is selected and assigned (by
013 * default {@link StandardNeighbourSelection} is employed).
014 * 
015 * @see Solver
016 * 
017 * @version IFS 1.3 (Iterative Forward Search)<br>
018 *          Copyright (C) 2006 - 2014 Tomáš Müller<br>
019 *          <a href="mailto:muller@unitime.org">muller@unitime.org</a><br>
020 *          <a href="http://muller.unitime.org">http://muller.unitime.org</a><br>
021 * <br>
022 *          This library is free software; you can redistribute it and/or modify
023 *          it under the terms of the GNU Lesser General Public License as
024 *          published by the Free Software Foundation; either version 3 of the
025 *          License, or (at your option) any later version. <br>
026 * <br>
027 *          This library is distributed in the hope that it will be useful, but
028 *          WITHOUT ANY WARRANTY; without even the implied warranty of
029 *          MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
030 *          Lesser General Public License for more details. <br>
031 * <br>
032 *          You should have received a copy of the GNU Lesser General Public
033 *          License along with this library; if not see <a href='http://www.gnu.org/licenses'>http://www.gnu.org/licenses</a>.
034 *
035 * @param <V> Variable
036 * @param <T> Value
037 **/
038public interface NeighbourSelection<V extends Variable<V, T>, T extends Value<V, T>> {
039    /** Criterion initialization 
040     * @param solver current solver
041     **/
042    public void init(Solver<V, T> solver);
043
044    /**
045     * select a neighbour of a given solution
046     * 
047     * @param solution
048     *            given solution
049     * @return a neighbour assignment
050     */
051    public Neighbour<V, T> selectNeighbour(Solution<V, T> solution);
052
053}