[3074] | 1 | #region License Information
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| 2 | /* HeuristicLab
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| 3 | * Copyright (C) 2002-2010 Heuristic and Evolutionary Algorithms Laboratory (HEAL)
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| 4 | *
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| 5 | * This file is part of HeuristicLab.
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| 6 | *
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| 7 | * HeuristicLab is free software: you can redistribute it and/or modify
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| 8 | * it under the terms of the GNU General Public License as published by
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| 9 | * the Free Software Foundation, either version 3 of the License, or
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| 10 | * (at your option) any later version.
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| 11 | *
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| 12 | * HeuristicLab is distributed in the hope that it will be useful,
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| 13 | * but WITHOUT ANY WARRANTY; without even the implied warranty of
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| 14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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| 15 | * GNU General Public License for more details.
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| 16 | *
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| 17 | * You should have received a copy of the GNU General Public License
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| 18 | * along with HeuristicLab. If not, see <http://www.gnu.org/licenses/>.
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| 19 | */
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| 20 | #endregion
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| 21 |
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| 22 | using System;
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| 23 | using HeuristicLab.Core;
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| 24 | using HeuristicLab.Data;
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| 25 | using HeuristicLab.Optimization;
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| 26 | using HeuristicLab.Parameters;
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| 27 | using HeuristicLab.Persistence.Default.CompositeSerializers.Storable;
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| 28 |
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| 29 | namespace HeuristicLab.Encodings.PermutationEncoding {
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| 30 | [Item("StochasticThreeOptMoveGenerator", "Randomly samples n from all possible 3-opt moves from a given permutation.")]
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| 31 | [StorableClass]
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| 32 | public class StochasticThreeOptMoveGenerator : ThreeOptMoveGenerator, IStochasticOperator {
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| 33 | public ILookupParameter<IRandom> RandomParameter {
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| 34 | get { return (ILookupParameter<IRandom>)Parameters["Random"]; }
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| 35 | }
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| 36 | private ValueLookupParameter<IntValue> SampleSizeParameter {
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| 37 | get { return (ValueLookupParameter<IntValue>)Parameters["SampleSize"]; }
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| 38 | }
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| 39 |
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| 40 | public IntValue SampleSize {
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| 41 | get { return SampleSizeParameter.Value; }
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| 42 | set { SampleSizeParameter.Value = value; }
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| 43 | }
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| 44 |
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| 45 | public StochasticThreeOptMoveGenerator()
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| 46 | : base() {
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| 47 | Parameters.Add(new LookupParameter<IRandom>("Random", "The random number generator."));
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| 48 | Parameters.Add(new ValueLookupParameter<IntValue>("SampleSize", "The number of moves to generate."));
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| 49 | }
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| 50 |
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| 51 | public static ThreeOptMove[] Apply(Permutation permutation, IRandom random, int sampleSize) {
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| 52 | int length = permutation.Length;
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| 53 | /*int totalMoves = (length) * (length - 1) / 2 - 3;
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| 54 | // FIXME: Remove this comment if ExhaustiveThreeOptMoveGenerator exists, otherwise alter the exception message below.
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| 55 | if (sampleSize >= totalMoves) throw new InvalidOperationException("StochasticThreeOptMoveGenerator: Sample size (" + sampleSize + ") is larger than the set of all possible moves (" + totalMoves + "), use the ExhaustiveThreeOptMoveGenerator instead.");
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| 56 | */
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| 57 | ThreeOptMove[] moves = new ThreeOptMove[sampleSize];
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| 58 | for (int i = 0; i < sampleSize; i++) {
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| 59 | int index1, index2, index3;
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| 60 | do {
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| 61 | index1 = random.Next(length - 1);
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| 62 | index2 = random.Next(index1 + 1, length);
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| 63 | } while (index2 - index1 == length - 1);
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| 64 | do {
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| 65 | index3 = random.Next(length);
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| 66 | } while (index1 <= index3 && index3 <= index2 + 1);
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| 67 | moves[i] = new ThreeOptMove(index1, index2, index3);
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| 68 | }
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| 69 | return moves;
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| 70 | }
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| 71 |
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| 72 | protected override ThreeOptMove[] GenerateMoves(Permutation permutation) {
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| 73 | IRandom random = RandomParameter.ActualValue;
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| 74 | return Apply(permutation, random, SampleSizeParameter.ActualValue.Value);
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| 75 | }
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| 76 | }
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| 77 | }
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