source: trunk/sources/HeuristicLab.Problems.DataAnalysis.Symbolic/3.4/SymbolicDataAnalysisExpressionPruningOperator.cs @ 12361

Last change on this file since 12361 was 12361, checked in by bburlacu, 6 years ago

#2359: The changes in r12358 look fine to me. Added total number of pruned nodes in the analyzer's data table. Removed unused parameter names in the SymbolicDataAnalysisSingleObjectivePruningAnalyzer.

File size: 10.1 KB
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1#region License Information
2
3/* HeuristicLab
4 * Copyright (C) 2002-2015 Heuristic and Evolutionary Algorithms Laboratory (HEAL)
5 *
6 * This file is part of HeuristicLab.
7 *
8 * HeuristicLab is free software: you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License as published by
10 * the Free Software Foundation, either version 3 of the License, or
11 * (at your option) any later version.
12 *
13 * HeuristicLab is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
16 * GNU General Public License for more details.
17 *
18 * You should have received a copy of the GNU General Public License
19 * along with HeuristicLab. If not, see <http://www.gnu.org/licenses/>.
20 */
21
22#endregion
23
24using System.Linq;
25using HeuristicLab.Common;
26using HeuristicLab.Core;
27using HeuristicLab.Data;
28using HeuristicLab.Encodings.SymbolicExpressionTreeEncoding;
29using HeuristicLab.Operators;
30using HeuristicLab.Parameters;
31using HeuristicLab.Persistence.Default.CompositeSerializers.Storable;
32
33namespace HeuristicLab.Problems.DataAnalysis.Symbolic {
34  [StorableClass]
35  [Item("SymbolicExpressionTreePruningOperator", "An operator that replaces introns with constant values in a symbolic expression tree.")]
36  public abstract class SymbolicDataAnalysisExpressionPruningOperator : SingleSuccessorOperator, ISymbolicExpressionTreeOperator {
37    #region parameter names
38    private const string ProblemDataParameterName = "ProblemData";
39    private const string SymbolicDataAnalysisModelParameterName = "SymbolicDataAnalysisModel";
40    private const string ImpactValuesCalculatorParameterName = "ImpactValuesCalculator";
41    private const string PrunedSubtreesParameterName = "PrunedSubtrees";
42    private const string PrunedTreesParameterName = "PrunedTrees";
43    private const string PrunedNodesParameterName = "PrunedNodes";
44    private const string FitnessCalculationPartitionParameterName = "FitnessCalculationPartition";
45    private const string NodeImpactThresholdParameterName = "ImpactThreshold";
46    private const string PruneOnlyZeroImpactNodesParameterName = "PruneOnlyZeroImpactNodes";
47    private const string SymbolicExpressionTreeParameterName = "SymbolicExpressionTree"; // the tree to be pruned
48    private const string QualityParameterName = "Quality"; // the quality
49    private const string EstimationLimitsParameterName = "EstimationLimits";
50    private const string InterpreterParameterName = "SymbolicExpressionTreeInterpreter";
51    #endregion
52
53    #region parameter properties
54    public ILookupParameter<ISymbolicExpressionTree> SymbolicExpressionTreeParameter {
55      get { return (ILookupParameter<ISymbolicExpressionTree>)Parameters[SymbolicExpressionTreeParameterName]; }
56    }
57    public ILookupParameter<DoubleValue> QualityParameter {
58      get { return (ILookupParameter<DoubleValue>)Parameters[QualityParameterName]; }
59    }
60    public ILookupParameter<IDataAnalysisProblemData> ProblemDataParameter {
61      get { return (ILookupParameter<IDataAnalysisProblemData>)Parameters[ProblemDataParameterName]; }
62    }
63    public IValueParameter<ISymbolicDataAnalysisSolutionImpactValuesCalculator> ImpactValuesCalculatorParameter {
64      get { return (IValueParameter<ISymbolicDataAnalysisSolutionImpactValuesCalculator>)Parameters[ImpactValuesCalculatorParameterName]; }
65    }
66    public ILookupParameter<IntRange> FitnessCalculationPartitionParameter {
67      get { return (ILookupParameter<IntRange>)Parameters[FitnessCalculationPartitionParameterName]; }
68    }
69    public ILookupParameter<IntValue> PrunedSubtreesParameter {
70      get { return (ILookupParameter<IntValue>)Parameters[PrunedSubtreesParameterName]; }
71    }
72    public ILookupParameter<IntValue> PrunedTreesParameter {
73      get { return (ILookupParameter<IntValue>)Parameters[PrunedTreesParameterName]; }
74    }
75    public ILookupParameter<IntValue> PrunedNodesParameter {
76      get { return (ILookupParameter<IntValue>)Parameters[PrunedNodesParameterName]; }
77    }
78    public IFixedValueParameter<DoubleValue> NodeImpactThresholdParameter {
79      get { return (IFixedValueParameter<DoubleValue>)Parameters[NodeImpactThresholdParameterName]; }
80    }
81    public IFixedValueParameter<BoolValue> PruneOnlyZeroImpactNodesParameter {
82      get { return (IFixedValueParameter<BoolValue>)Parameters[PruneOnlyZeroImpactNodesParameterName]; }
83    }
84    public ILookupParameter<DoubleLimit> EstimationLimitsParameter {
85      get { return (ILookupParameter<DoubleLimit>)Parameters[EstimationLimitsParameterName]; }
86    }
87    public ILookupParameter<ISymbolicDataAnalysisExpressionTreeInterpreter> InterpreterParameter {
88      get { return (ILookupParameter<ISymbolicDataAnalysisExpressionTreeInterpreter>)Parameters[InterpreterParameterName]; }
89    }
90    #endregion
91
92    #region properties
93    public ISymbolicDataAnalysisSolutionImpactValuesCalculator ImpactValuesCalculator {
94      get { return ImpactValuesCalculatorParameter.Value; }
95      set { ImpactValuesCalculatorParameter.Value = value; }
96    }
97    public bool PruneOnlyZeroImpactNodes {
98      get { return PruneOnlyZeroImpactNodesParameter.Value.Value; }
99      set { PruneOnlyZeroImpactNodesParameter.Value.Value = value; }
100    }
101    public double NodeImpactThreshold {
102      get { return NodeImpactThresholdParameter.Value.Value; }
103      set { NodeImpactThresholdParameter.Value.Value = value; }
104    }
105    #endregion
106
107    [StorableConstructor]
108    protected SymbolicDataAnalysisExpressionPruningOperator(bool deserializing) : base(deserializing) { }
109    protected SymbolicDataAnalysisExpressionPruningOperator(SymbolicDataAnalysisExpressionPruningOperator original, Cloner cloner)
110      : base(original, cloner) { }
111
112    protected SymbolicDataAnalysisExpressionPruningOperator(ISymbolicDataAnalysisSolutionImpactValuesCalculator impactValuesCalculator) {
113      #region add parameters
114      Parameters.Add(new LookupParameter<IDataAnalysisProblemData>(ProblemDataParameterName));
115      Parameters.Add(new LookupParameter<ISymbolicDataAnalysisModel>(SymbolicDataAnalysisModelParameterName));
116      Parameters.Add(new LookupParameter<IntRange>(FitnessCalculationPartitionParameterName));
117      Parameters.Add(new LookupParameter<IntValue>(PrunedNodesParameterName, "A counter of how many nodes were pruned."));
118      Parameters.Add(new LookupParameter<IntValue>(PrunedSubtreesParameterName, "A counter of how many subtrees were replaced."));
119      Parameters.Add(new LookupParameter<IntValue>(PrunedTreesParameterName, "A counter of how many trees were pruned."));
120      Parameters.Add(new FixedValueParameter<BoolValue>(PruneOnlyZeroImpactNodesParameterName, "Specify whether or not only zero impact nodes should be pruned."));
121      Parameters.Add(new FixedValueParameter<DoubleValue>(NodeImpactThresholdParameterName, "Specifies an impact value threshold below which nodes should be pruned."));
122      Parameters.Add(new LookupParameter<DoubleLimit>(EstimationLimitsParameterName));
123      Parameters.Add(new LookupParameter<ISymbolicDataAnalysisExpressionTreeInterpreter>(InterpreterParameterName));
124      Parameters.Add(new LookupParameter<ISymbolicExpressionTree>(SymbolicExpressionTreeParameterName));
125      Parameters.Add(new LookupParameter<DoubleValue>(QualityParameterName));
126      Parameters.Add(new ValueParameter<ISymbolicDataAnalysisSolutionImpactValuesCalculator>(ImpactValuesCalculatorParameterName, impactValuesCalculator));
127      #endregion
128    }
129
130    protected abstract ISymbolicDataAnalysisModel CreateModel(ISymbolicExpressionTree tree, ISymbolicDataAnalysisExpressionTreeInterpreter interpreter, IDataAnalysisProblemData problemData, DoubleLimit estimationLimits);
131
132    protected abstract double Evaluate(IDataAnalysisModel model);
133
134    public override IOperation Apply() {
135      var tree = SymbolicExpressionTreeParameter.ActualValue;
136      var problemData = ProblemDataParameter.ActualValue;
137      var fitnessCalculationPartition = FitnessCalculationPartitionParameter.ActualValue;
138      var estimationLimits = EstimationLimitsParameter.ActualValue;
139      var interpreter = InterpreterParameter.ActualValue;
140
141      var model = CreateModel(tree, interpreter, problemData, estimationLimits);
142      var nodes = tree.Root.GetSubtree(0).GetSubtree(0).IterateNodesPrefix().ToList();
143      var rows = Enumerable.Range(fitnessCalculationPartition.Start, fitnessCalculationPartition.Size);
144      var prunedSubtrees = 0;
145      var prunedTrees = 0;
146      var prunedNodes = 0;
147
148      double quality = Evaluate(model);
149
150      for (int i = 0; i < nodes.Count; ++i) {
151        var node = nodes[i];
152        if (node is ConstantTreeNode) continue;
153
154        double impactValue, replacementValue;
155        ImpactValuesCalculator.CalculateImpactAndReplacementValues(model, node, problemData, rows, out impactValue, out replacementValue, quality);
156
157        if (PruneOnlyZeroImpactNodes && !impactValue.IsAlmost(0.0)) continue;
158        if (!PruneOnlyZeroImpactNodes && impactValue > NodeImpactThreshold) continue;
159
160        var constantNode = (ConstantTreeNode)node.Grammar.GetSymbol("Constant").CreateTreeNode();
161        constantNode.Value = replacementValue;
162
163        var length = node.GetLength();
164        ReplaceWithConstant(node, constantNode);
165        i += length - 1; // skip subtrees under the node that was folded
166
167        quality -= impactValue;
168        prunedSubtrees++;
169        prunedNodes += length;
170      }
171
172      if (prunedSubtrees > 0) prunedTrees = 1;
173      PrunedSubtreesParameter.ActualValue = new IntValue(prunedSubtrees);
174      PrunedTreesParameter.ActualValue = new IntValue(prunedTrees);
175      PrunedNodesParameter.ActualValue = new IntValue(prunedNodes);
176      QualityParameter.ActualValue.Value = quality;
177
178      return base.Apply();
179    }
180
181    protected static void ReplaceWithConstant(ISymbolicExpressionTreeNode original, ISymbolicExpressionTreeNode replacement) {
182      var parent = original.Parent;
183      var i = parent.IndexOfSubtree(original);
184      parent.RemoveSubtree(i);
185      parent.InsertSubtree(i, replacement);
186    }
187  }
188}
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