1 | #region License Information
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2 | /* HeuristicLab
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3 | * Copyright (C) 2002-2008 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.Collections.Generic;
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24 | using System.Text;
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25 | using HeuristicLab.Core;
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26 | using HeuristicLab.Data;
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27 |
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28 | namespace HeuristicLab.Operators {
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29 | /// <summary>
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30 | /// Branch of operators that have different probabilities to get executed.
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31 | /// </summary>
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32 | public class StochasticMultiBranch : OperatorBase {
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33 | ///<inheritdoc select="summary"/>
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34 | public override string Description {
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35 | get { return @"TODO\r\nOperator description still missing ..."; }
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36 | }
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37 |
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38 | /// <summary>
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39 | /// Initializes a new instance of <see cref="StochasticMultiBranch"/> with two variable infos
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40 | /// (<c>Probabilities</c> and <c>Random</c>).
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41 | /// </summary>
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42 | public StochasticMultiBranch()
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43 | : base() {
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44 | AddVariableInfo(new VariableInfo("Probabilities", "The probabilities, that define how likely each suboperator/graph is executed. This array must sum to 1", typeof(DoubleArrayData), VariableKind.In));
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45 | AddVariableInfo(new VariableInfo("Random", "The pseudo random-generator, used for any random-decision.", typeof(IRandom), VariableKind.In));
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46 | }
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47 |
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48 | /// <summary>
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49 | /// Applies an operator of the branches to the specified <paramref name="scope"/> with a
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50 | /// specific probability.
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51 | /// </summary>
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52 | /// <exception cref="InvalidOperationException">Thrown when the list of probabilites does not
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53 | /// match the number of operators or if there was another problem with the list of probabilities.</exception>
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54 | /// <param name="scope">The scope to apply the operators on.</param>
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55 | /// <returns>A new <see cref="AtomicOperation"/> with a specific operator, depending
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56 | /// on its probability, applied on the given <paramref name="scope"/>.</returns>
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57 | public override IOperation Apply(IScope scope) {
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58 | IRandom random = GetVariableValue<IRandom>("Random", scope, true);
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59 | DoubleArrayData probabilities = GetVariableValue<DoubleArrayData>("Probabilities", scope, true);
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60 | if(probabilities.Data.Length != SubOperators.Count) {
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61 | throw new InvalidOperationException("StochasticMultiBranch: The list of probabilities has to match the number of operators");
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62 | }
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63 | double sum = 0;
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64 | foreach(double prob in probabilities.Data) {
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65 | sum+=prob;
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66 | }
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67 | double r = random.NextDouble()*sum;
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68 | sum = 0;
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69 | IOperator successor = null;
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70 | for(int i = 0; i < SubOperators.Count; i++) {
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71 | sum += probabilities.Data[i];
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72 | if(sum > r) {
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73 | successor = SubOperators[i];
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74 | break;
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75 | }
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76 | }
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77 | if(successor == null) {
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78 | throw new InvalidOperationException("StochasticMultiBranch: There was a problem with the list of probabilities");
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79 | }
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80 | return new AtomicOperation(successor, scope);
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81 | }
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82 | }
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83 | }
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