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.Collections.Generic;
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24 | using System.Linq;
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25 | using System.Threading;
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26 | using System.Threading.Tasks;
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27 | using HeuristicLab.Common;
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28 | using HeuristicLab.Core;
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29 | using HeuristicLab.Data;
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30 | using HeuristicLab.Parameters;
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31 | using HeuristicLab.Persistence.Default.CompositeSerializers.Storable;
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32 |
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33 | namespace HeuristicLab.Optimization.Algorithms.SingleObjective {
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34 | public abstract class HeuristicAlgorithm<TContext, TProblem, TEncoding, TSolution> : Algorithm
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35 | where TContext : HeuristicAlgorithmContext<TProblem, TEncoding, TSolution>,
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36 | IStochasticContext, IEvaluatedSolutionsContext, IBestQualityContext,
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37 | IBestSolutionContext<TSolution>, new()
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38 | where TProblem : class, ISingleObjectiveProblem<TEncoding, TSolution>, ISingleObjectiveProblemDefinition<TEncoding, TSolution>
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39 | where TEncoding : class, IEncoding<TSolution>
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40 | where TSolution : class, ISolution {
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41 | private Type problemType;
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42 |
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43 | public override Type ProblemType {
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44 | get { return typeof(SingleObjectiveProblem<TEncoding, TSolution>); }
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45 | }
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46 |
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47 | public new TProblem Problem {
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48 | get { return (TProblem)base.Problem; }
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49 | set { base.Problem = value; }
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50 | }
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51 |
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52 | private CancellationTokenSource cancellationTokenSource;
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53 | protected CancellationTokenSource CancellationTokenSource {
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54 | get { return cancellationTokenSource; }
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55 | private set { cancellationTokenSource = value; }
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56 | }
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57 |
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58 |
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59 | public int? MaximumEvaluations {
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60 | get {
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61 | var val = ((OptionalValueParameter<IntValue>)Parameters["MaximumEvaluations"]).Value;
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62 | return val != null ? val.Value : (int?)null;
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63 | }
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64 | set {
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65 | var param = (OptionalValueParameter<IntValue>)Parameters["MaximumEvaluations"];
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66 | param.Value = value.HasValue ? new IntValue(value.Value) : null;
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67 | }
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68 | }
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69 |
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70 | public TimeSpan? MaximumExecutionTime {
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71 | get {
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72 | var val = ((OptionalValueParameter<TimeSpanValue>)Parameters["MaximumExecutionTime"]).Value;
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73 | return val != null ? val.Value : (TimeSpan?)null;
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74 | }
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75 | set {
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76 | var param = (OptionalValueParameter<TimeSpanValue>)Parameters["MaximumExecutionTime"];
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77 | param.Value = value.HasValue ? new TimeSpanValue(value.Value) : null;
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78 | }
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79 | }
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80 |
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81 | public double? TargetQuality {
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82 | get {
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83 | var val = ((OptionalValueParameter<DoubleValue>)Parameters["TargetQuality"]).Value;
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84 | return val != null ? val.Value : (double?)null;
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85 | }
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86 | set {
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87 | var param = (OptionalValueParameter<DoubleValue>)Parameters["TargetQuality"];
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88 | param.Value = value.HasValue ? new DoubleValue(value.Value) : null;
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89 | }
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90 | }
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91 |
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92 | public bool SetSeedRandomly {
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93 | get { return ((FixedValueParameter<BoolValue>)Parameters["SetSeedRandomly"]).Value.Value; }
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94 | set { ((FixedValueParameter<BoolValue>)Parameters["SetSeedRandomly"]).Value.Value = value; }
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95 | }
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96 |
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97 | public int Seed {
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98 | get { return ((FixedValueParameter<IntValue>)Parameters["Seed"]).Value.Value; }
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99 | set { ((FixedValueParameter<IntValue>)Parameters["Seed"]).Value.Value = value; }
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100 | }
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101 |
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102 | public IMultiAnalyzer AlgorithmAnalyzer {
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103 | get { return ((ValueParameter<IMultiAnalyzer>)Parameters["Analyzer.Algorithm"]).Value; }
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104 | set { ((ValueParameter<IMultiAnalyzer>)Parameters["Analyzer.Algorithm"]).Value = value; }
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105 | }
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106 |
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107 | public IMultiAnalyzer ProblemAnalyzer {
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108 | get { return ((ValueParameter<IMultiAnalyzer>)Parameters["Analyzer.Problem"]).Value; }
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109 | set { ((ValueParameter<IMultiAnalyzer>)Parameters["Analyzer.Problem"]).Value = value; }
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110 | }
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111 |
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112 | [Storable]
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113 | private ResultCollection results;
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114 | public override ResultCollection Results {
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115 | get { return results; }
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116 | }
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117 |
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118 | [Storable]
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119 | private TContext context;
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120 | public TContext Context {
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121 | get { return context; }
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122 | protected set {
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123 | if (context == value) return;
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124 | context = value;
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125 | }
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126 | }
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127 |
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128 | [StorableConstructor]
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129 | protected HeuristicAlgorithm(bool deserializing) : base(deserializing) { }
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130 | protected HeuristicAlgorithm(HeuristicAlgorithm<TContext, TProblem, TEncoding, TSolution> original, Cloner cloner)
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131 | : base(original, cloner) { }
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132 | protected HeuristicAlgorithm() {
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133 | results = new ResultCollection();
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134 |
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135 | Parameters.Add(new ValueParameter<IMultiAnalyzer>("Analyzer.Algorithm", "The algorithm's analyzers to apply to the solution(s) (independent of the problem)."));
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136 | Parameters.Add(new ValueParameter<IMultiAnalyzer>("Analyzer.Problem", "The problem's analyzer to apply to the solution(s)."));
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137 | Parameters.Add(new OptionalValueParameter<IntValue>("MaximumEvaluations", "The maximum number of solution evaluations."));
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138 | Parameters.Add(new OptionalValueParameter<TimeSpanValue>("MaximumExecutionTime", "The maximum runtime.", new TimeSpanValue(TimeSpan.FromMinutes(1))));
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139 | Parameters.Add(new OptionalValueParameter<DoubleValue>("TargetQuality", "The target quality at which the algorithm terminates."));
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140 | Parameters.Add(new FixedValueParameter<BoolValue>("SetSeedRandomly", "Whether each run of the algorithm should be conducted with a new random seed.", new BoolValue(true)));
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141 | Parameters.Add(new FixedValueParameter<IntValue>("Seed", "The random number seed that is used in case SetSeedRandomly is false.", new IntValue(0)));
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142 |
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143 | }
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144 |
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145 | protected override void OnProblemChanged() {
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146 | base.OnProblemChanged();
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147 | if (ProblemAnalyzer != null) {
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148 | ProblemAnalyzer.Operators.Clear();
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149 | if (Problem != null) {
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150 | foreach (var analyzer in Problem.Operators.OfType<IAnalyzer>()) {
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151 | foreach (var param in analyzer.Parameters.OfType<IScopeTreeLookupParameter>())
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152 | param.Depth = 1;
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153 | ProblemAnalyzer.Operators.Add(analyzer, analyzer.EnabledByDefault);
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154 | }
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155 | }
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156 | }
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157 | }
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158 |
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159 | public override void Prepare() {
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160 | if (Problem == null) return;
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161 | base.Prepare();
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162 | results.Clear();
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163 | Context = null;
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164 | stopRequested = false;
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165 | OnPrepared();
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166 | }
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167 |
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168 | private bool stopRequested = false;
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169 | public override void Start() {
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170 | base.Start();
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171 | CancellationTokenSource = new CancellationTokenSource();
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172 |
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173 | OnStarted();
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174 | var task = Task.Run((Action)Run, cancellationTokenSource.Token);
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175 | var continuation = new Task[3];
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176 | continuation[0] = task.ContinueWith(t => {
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177 | if (t.Exception != null) {
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178 | OnExceptionOccurred(t.Exception.InnerExceptions.Count == 1 ? t.Exception.InnerExceptions[0] : t.Exception);
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179 | }
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180 | OnPaused();
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181 | }, TaskContinuationOptions.OnlyOnFaulted);
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182 | continuation[1] = task.ContinueWith(t => {
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183 | OnStopped();
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184 | }, TaskContinuationOptions.OnlyOnRanToCompletion);
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185 | continuation[2] = task.ContinueWith(t => {
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186 | if (stopRequested) OnStopped();
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187 | else OnPaused();
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188 | }, TaskContinuationOptions.OnlyOnCanceled);
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189 | Task.WhenAny(continuation).ContinueWith(_ => {
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190 | CancellationTokenSource.Dispose();
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191 | CancellationTokenSource = null;
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192 | });
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193 | }
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194 |
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195 | public override void Pause() {
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196 | base.Pause();
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197 | CancellationTokenSource.Cancel();
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198 | }
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199 |
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200 | public override void Stop() {
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201 | // CancellationToken.ThrowIfCancellationRequested() must be called from within the Run method, otherwise stop does nothing
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202 | // alternatively check the IsCancellationRequested property of the cancellation token
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203 | base.Stop();
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204 | stopRequested = true;
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205 | if (CancellationTokenSource != null) {
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206 | try {
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207 | CancellationTokenSource.Cancel();
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208 | } catch {
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209 | OnStopped();
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210 | }
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211 | } else OnStopped();
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212 | }
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213 |
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214 | private DateTime lastUpdateTime;
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215 | private void Run() {
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216 | var token = CancellationTokenSource.Token;
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217 | lastUpdateTime = DateTime.UtcNow;
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218 | System.Timers.Timer timer = new System.Timers.Timer(250);
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219 | timer.AutoReset = true;
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220 | timer.Elapsed += timer_Elapsed;
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221 | timer.Start();
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222 | try {
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223 | if (context == null) {
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224 | context = CreateContext();
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225 |
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226 | IExecutionContext ctxt = null;
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227 | foreach (var item in Problem.ExecutionContextItems)
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228 | ctxt = new Core.ExecutionContext(ctxt, item, Context.Scope);
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229 | ctxt = new Core.ExecutionContext(ctxt, this, Context.Scope);
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230 |
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231 | context.Parent = ctxt;
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232 |
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233 | if (SetSeedRandomly) Seed = new System.Random().Next();
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234 | Context.Random.Reset(Seed);
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235 | Context.Scope.Variables.Add(new Variable("Results", Results));
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236 | } else context.CancellationToken = token;
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237 |
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238 | if (!Context.Initialized) {
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239 | try {
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240 | PerformInitialize(token);
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241 | } catch {
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242 | context = null;
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243 | return;
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244 | }
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245 | Context.Initialized = true;
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246 | }
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247 |
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248 | while (!CheckTerminate(token)) {
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249 | PerformIterate(token);
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250 | PerformAnalyze(token);
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251 | token.ThrowIfCancellationRequested();
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252 | }
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253 | } finally {
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254 | timer.Elapsed -= timer_Elapsed;
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255 | timer.Stop();
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256 | ExecutionTime += DateTime.UtcNow - lastUpdateTime;
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257 | }
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258 | }
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259 |
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260 | protected virtual TContext CreateContext() {
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261 | return new TContext() { Problem = Problem, CancellationToken = CancellationTokenSource.Token };
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262 | }
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263 |
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264 | protected virtual ISingleObjectiveSolutionScope<TSolution> CreateEmptySolutionScope() {
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265 | return new SingleObjectiveSolutionScope<TSolution>(null, Problem.Encoding.Name, double.NaN, Problem.Evaluator.QualityParameter.ActualName);
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266 | }
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267 |
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268 | protected static bool IsBetter(bool maximization, double a, double b) {
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269 | return !double.IsNaN(a) && double.IsNaN(b) || maximization && a > b || !maximization && a < b;
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270 | }
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271 |
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272 | protected virtual void Evaluate(ISingleObjectiveSolutionScope<TSolution> scope, CancellationToken token) {
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273 | scope.Fitness = Problem.Evaluate(scope.Solution, Context.Random);
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274 | }
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275 |
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276 | protected abstract void PerformInitialize(CancellationToken token);
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277 | protected abstract void PerformIterate(CancellationToken token);
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278 | protected virtual void PerformAnalyze(CancellationToken token) {
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279 | IResult res;
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280 | if (!Results.TryGetValue("EvaluatedSolutions", out res)) {
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281 | res = new Result("EvaluatedSolutions", new IntValue(Context.EvaluatedSolutions));
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282 | Results.Add(res);
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283 | } else ((IntValue)res.Value).Value = Context.EvaluatedSolutions;
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284 | if (!Results.TryGetValue("BestQuality", out res)) {
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285 | res = new Result("BestQuality", new DoubleValue(Context.BestQuality));
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286 | Results.Add(res);
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287 | } else ((DoubleValue)res.Value).Value = Context.BestQuality;
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288 |
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289 | RunOperator(ProblemAnalyzer, Context.Scope, token);
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290 | RunOperator(AlgorithmAnalyzer, Context.Scope, token);
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291 | }
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292 |
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293 | protected virtual bool CheckTerminate(CancellationToken token) {
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294 | return MaximumEvaluations.HasValue && Context.EvaluatedSolutions >= MaximumEvaluations.Value
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295 | || MaximumExecutionTime.HasValue && ExecutionTime >= MaximumExecutionTime.Value
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296 | || TargetQuality.HasValue && (Problem.Maximization && Context.BestQuality >= TargetQuality.Value
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297 | || !Problem.Maximization && Context.BestQuality <= TargetQuality.Value);
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298 | }
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299 |
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300 | #region Engine Helper
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301 | protected void RunOperator(IOperator op, IScope scope, CancellationToken cancellationToken) {
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302 | var stack = new Stack<IOperation>();
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303 | stack.Push(Context.CreateChildOperation(op, scope));
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304 |
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305 | while (stack.Count > 0) {
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306 | cancellationToken.ThrowIfCancellationRequested();
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307 |
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308 | var next = stack.Pop();
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309 | if (next is OperationCollection) {
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310 | var coll = (OperationCollection)next;
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311 | for (int i = coll.Count - 1; i >= 0; i--)
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312 | if (coll[i] != null) stack.Push(coll[i]);
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313 | } else if (next is IAtomicOperation) {
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314 | var operation = (IAtomicOperation)next;
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315 | try {
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316 | next = operation.Operator.Execute((IExecutionContext)operation, cancellationToken);
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317 | } catch (Exception ex) {
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318 | stack.Push(operation);
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319 | if (ex is OperationCanceledException) throw ex;
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320 | else throw new OperatorExecutionException(operation.Operator, ex);
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321 | }
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322 | if (next != null) stack.Push(next);
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323 | }
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324 | }
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325 | }
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326 | #endregion
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327 |
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328 | #region Events
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329 | private void timer_Elapsed(object sender, System.Timers.ElapsedEventArgs e) {
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330 | System.Timers.Timer timer = (System.Timers.Timer)sender;
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331 | timer.Enabled = false;
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332 | DateTime now = DateTime.UtcNow;
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333 | ExecutionTime += now - lastUpdateTime;
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334 | lastUpdateTime = now;
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335 | timer.Enabled = true;
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336 | }
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337 | #endregion
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338 | }
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339 | }
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