source: branches/2521_ProblemRefactoring/HeuristicLab.Optimization/3.3/BasicProblems/Operators/SingleObjectiveImprover.cs @ 17366

Last change on this file since 17366 was 17366, checked in by mkommend, 3 years ago

#2521: Fixed bugs in solution context and adapted programmable problem template to include a cancellation token in the evaluate function.

File size: 6.1 KB
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1#region License Information
2/* HeuristicLab
3 * Copyright (C) Heuristic and Evolutionary Algorithms Laboratory (HEAL)
4 *
5 * This file is part of HeuristicLab.
6 *
7 * HeuristicLab is free software: you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation, either version 3 of the License, or
10 * (at your option) any later version.
11 *
12 * HeuristicLab is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15 * GNU General Public License for more details.
16 *
17 * You should have received a copy of the GNU General Public License
18 * along with HeuristicLab. If not, see <http://www.gnu.org/licenses/>.
19 */
20#endregion
21
22using System;
23using System.Collections.Generic;
24using System.Linq;
25using System.Threading;
26using HEAL.Attic;
27using HeuristicLab.Common;
28using HeuristicLab.Core;
29using HeuristicLab.Data;
30using HeuristicLab.Operators;
31using HeuristicLab.Parameters;
32
33namespace HeuristicLab.Optimization {
34  [Item("Single-objective Improver", "Improves a solution by calling GetNeighbors and Evaluate of the corresponding problem definition.")]
35  [StorableType("7A917E09-920C-4B47-9599-67371101B35F")]
36  internal sealed class SingleObjectiveImprover<TEncodedSolution> : SingleSuccessorOperator, INeighborBasedOperator<TEncodedSolution>, IImprovementOperator, ISingleObjectiveEvaluationOperator<TEncodedSolution>, IStochasticOperator
37    where TEncodedSolution : class, IEncodedSolution {
38    public ILookupParameter<IRandom> RandomParameter {
39      get { return (ILookupParameter<IRandom>)Parameters["Random"]; }
40    }
41
42    public ILookupParameter<IEncoding<TEncodedSolution>> EncodingParameter {
43      get { return (ILookupParameter<IEncoding<TEncodedSolution>>)Parameters["Encoding"]; }
44    }
45
46    public ILookupParameter<DoubleValue> QualityParameter {
47      get { return (ILookupParameter<DoubleValue>)Parameters["Quality"]; }
48    }
49
50    public ILookupParameter<BoolValue> MaximizationParameter {
51      get { return (ILookupParameter<BoolValue>)Parameters["Maximization"]; }
52    }
53
54    public IValueLookupParameter<IntValue> ImprovementAttemptsParameter {
55      get { return (IValueLookupParameter<IntValue>)Parameters["ImprovementAttempts"]; }
56    }
57
58    public IValueLookupParameter<IntValue> SampleSizeParameter {
59      get { return (IValueLookupParameter<IntValue>)Parameters["SampleSize"]; }
60    }
61
62    public ILookupParameter<IntValue> LocalEvaluatedSolutionsParameter {
63      get { return (ILookupParameter<IntValue>)Parameters["LocalEvaluatedSolutions"]; }
64    }
65
66    public Action<ISingleObjectiveSolutionContext<TEncodedSolution>, IRandom, CancellationToken> Evaluate { get; set; }
67    public Func<ISingleObjectiveSolutionContext<TEncodedSolution>, IRandom, IEnumerable<ISingleObjectiveSolutionContext<TEncodedSolution>>> GetNeighbors { get; set; }
68
69    [StorableConstructor]
70    private SingleObjectiveImprover(StorableConstructorFlag _) : base(_) { }
71    private SingleObjectiveImprover(SingleObjectiveImprover<TEncodedSolution> original, Cloner cloner) : base(original, cloner) { }
72    public SingleObjectiveImprover() {
73      Parameters.Add(new LookupParameter<IRandom>("Random", "The random number generator to use."));
74      Parameters.Add(new LookupParameter<IEncoding<TEncodedSolution>>("Encoding", "An item that holds the problem's encoding."));
75      Parameters.Add(new LookupParameter<DoubleValue>("Quality", "The quality of the parameter vector."));
76      Parameters.Add(new LookupParameter<BoolValue>("Maximization", "Whether the problem should be minimized or maximized."));
77      Parameters.Add(new ValueLookupParameter<IntValue>("ImprovementAttempts", "The number of improvement attempts the operator should perform.", new IntValue(100)));
78      Parameters.Add(new ValueLookupParameter<IntValue>("SampleSize", "The number of samples to draw from the neighborhood function at maximum.", new IntValue(300)));
79      Parameters.Add(new LookupParameter<IntValue>("LocalEvaluatedSolutions", "The number of solution evaluations that have been performed."));
80    }
81
82    public override IDeepCloneable Clone(Cloner cloner) {
83      return new SingleObjectiveImprover<TEncodedSolution>(this, cloner);
84    }
85
86    public override IOperation Apply() {
87      var random = RandomParameter.ActualValue;
88      var encoding = EncodingParameter.ActualValue;
89      var maximize = MaximizationParameter.ActualValue.Value;
90      var maxAttempts = ImprovementAttemptsParameter.ActualValue.Value;
91      var sampleSize = SampleSizeParameter.ActualValue.Value;
92      var solution = ScopeUtil.GetEncodedSolution(ExecutionContext.Scope, encoding);
93      var solutionContext = new SingleObjectiveSolutionContextScope<TEncodedSolution>(ExecutionContext.Scope, solution);
94
95      double quality;
96      if (QualityParameter.ActualValue == null) {
97        if (!solutionContext.IsEvaluated) Evaluate(solutionContext, random, CancellationToken.None);
98
99        quality = solutionContext.EvaluationResult.Quality;
100      } else quality = QualityParameter.ActualValue.Value;
101
102      var count = 0;
103      for (var i = 0; i < maxAttempts; i++) {
104        TEncodedSolution best = default(TEncodedSolution);
105        var bestQuality = quality;
106        foreach (var neighbor in GetNeighbors(solutionContext, random).Take(sampleSize)) {
107          Evaluate(neighbor, random, CancellationToken);
108          var q = neighbor.EvaluationResult.Quality;
109          count++;
110          if (maximize && bestQuality > q || !maximize && bestQuality < q) continue;
111          best = neighbor.EncodedSolution;
112          bestQuality = q;
113        }
114        if (best == null) break;
115        solution = best;
116        quality = bestQuality;
117      }
118
119      LocalEvaluatedSolutionsParameter.ActualValue = new IntValue(count);
120      QualityParameter.ActualValue = new DoubleValue(quality);
121
122      ScopeUtil.CopyEncodedSolutionToScope(ExecutionContext.Scope, encoding, solution);
123      return base.Apply();
124    }
125  }
126}
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