1 | #region License Information
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2 | /* HeuristicLab
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3 | * Copyright (C) 2002-2016 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 System.Threading;
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24 | using HeuristicLab.Algorithms.MemPR.Util;
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25 | using HeuristicLab.Core;
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26 | using HeuristicLab.Encodings.PermutationEncoding;
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27 |
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28 | namespace HeuristicLab.Algorithms.MemPR.Permutation.LocalSearch {
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29 | public static class ExhaustiveSwap2 {
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30 | public static Tuple<int, int> HillClimb(IRandom random, Encodings.PermutationEncoding.Permutation perm,
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31 | ref double quality, bool maximization, Func<Encodings.PermutationEncoding.Permutation, double> eval,
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32 | CancellationToken token, bool[,] noTouch = null) {
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33 | var current = perm;
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34 | if (double.IsNaN(quality)) quality = eval(current);
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35 | Swap2Move lastSuccessMove = null;
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36 | int steps = 0, evaluations = 0;
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37 | while (true) {
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38 | foreach (var swap in ExhaustiveSwap2MoveGenerator.Generate(current)) {
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39 | if (lastSuccessMove != null && swap.Index1 == lastSuccessMove.Index1 && swap.Index2 == lastSuccessMove.Index2) {
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40 | // been there, done that
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41 | lastSuccessMove = null;
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42 | break;
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43 | }
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44 | if (noTouch != null && (noTouch[swap.Index1, 0] || noTouch[swap.Index2, 0]))
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45 | continue;
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46 |
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47 | var h = current[swap.Index1];
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48 | current[swap.Index1] = current[swap.Index2];
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49 | current[swap.Index2] = h;
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50 | var q = eval(current);
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51 | evaluations++;
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52 | if (FitnessComparer.IsBetter(maximization, q, quality)) {
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53 | steps++;
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54 | quality = q;
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55 | lastSuccessMove = swap;
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56 | } else {
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57 | current[swap.Index2] = current[swap.Index1];
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58 | current[swap.Index1] = h;
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59 | }
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60 |
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61 | if (token.IsCancellationRequested) {
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62 | lastSuccessMove = null;
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63 | break;
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64 | }
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65 | }
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66 | if (lastSuccessMove == null) break;
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67 | }
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68 | return Tuple.Create(steps, evaluations);
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69 | }
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70 | }
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71 | }
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