source: branches/2886_SymRegGrammarEnumeration/HeuristicLab.Algorithms.DataAnalysis.SymRegGrammarEnumeration/GrammarEnumeration/GrammarEnumerationAlgorithm.cs @ 15746

Last change on this file since 15746 was 15746, checked in by lkammere, 20 months ago

#2886: Refactor grammar enumeration alg.

File size: 12.0 KB
Line 
1using System.Collections.Generic;
2using System.Linq;
3using System.Threading;
4using HeuristicLab.Algorithms.DataAnalysis.SymRegGrammarEnumeration.GrammarEnumeration;
5using HeuristicLab.Common;
6using HeuristicLab.Core;
7using HeuristicLab.Data;
8using HeuristicLab.Encodings.SymbolicExpressionTreeEncoding;
9using HeuristicLab.Optimization;
10using HeuristicLab.Parameters;
11using HeuristicLab.Persistence.Default.CompositeSerializers.Storable;
12using HeuristicLab.Problems.DataAnalysis;
13using HeuristicLab.Problems.DataAnalysis.Symbolic;
14using HeuristicLab.Problems.DataAnalysis.Symbolic.Regression;
15
16namespace HeuristicLab.Algorithms.DataAnalysis.SymRegGrammarEnumeration {
17  [Item("Grammar Enumeration Symbolic Regression", "Iterates all possible model structures for a fixed grammar.")]
18  [StorableClass]
19  [Creatable(CreatableAttribute.Categories.DataAnalysisRegression, Priority = 250)]
20  public class GrammarEnumerationAlgorithm : FixedDataAnalysisAlgorithm<IRegressionProblem> {
21    #region properties and result names
22    private readonly string BestTrainingQualityName = "Best R² (Training)";
23    private readonly string BestTrainingSolutionName = "Best solution (Training)";
24    private readonly string GeneratedSentencesName = "Generated Sentences";
25    private readonly string DistinctSentencesName = "Distinct Sentences";
26    private readonly string PhraseExpansionsName = "Phrase Expansions";
27    private readonly string AverageTreeLengthName = "Avg. Sentence Length among Distinct";
28    private readonly string GeneratedEqualSentencesName = "Generated equal sentences";
29
30
31    private readonly string SearchDataStructureParameterName = "Search Data Structure";
32    private readonly string MaxTreeSizeParameterName = "Max. Tree Nodes";
33    private readonly string GuiUpdateIntervalParameterName = "GUI Update Interval";
34   
35    public override bool SupportsPause { get { return false; } }
36
37    protected IValueParameter<IntValue> MaxTreeSizeParameter {
38      get { return (IValueParameter<IntValue>)Parameters[MaxTreeSizeParameterName]; }
39    }
40    public int MaxTreeSize {
41      get { return MaxTreeSizeParameter.Value.Value; }
42      set { MaxTreeSizeParameter.Value.Value = value; }
43    }
44
45    protected IValueParameter<IntValue> GuiUpdateIntervalParameter {
46      get { return (IValueParameter<IntValue>)Parameters[GuiUpdateIntervalParameterName]; }
47    }
48    public int GuiUpdateInterval {
49      get { return GuiUpdateIntervalParameter.Value.Value; }
50      set { GuiUpdateIntervalParameter.Value.Value = value; }
51    }
52
53    protected IValueParameter<EnumValue<StorageType>> SearchDataStructureParameter {
54      get { return (IValueParameter<EnumValue<StorageType>>)Parameters[SearchDataStructureParameterName]; }
55    }
56    public StorageType SearchDataStructure {
57      get { return SearchDataStructureParameter.Value.Value; }
58      set { SearchDataStructureParameter.Value.Value = value; }
59    }
60
61    public SymbolString BestTrainingSentence;
62
63    #endregion
64
65    public Dictionary<int, SymbolString> DistinctSentences;   // Semantically distinct sentences in a run.
66    public Dictionary<int, List<SymbolString>> AllSentences;  // All sentences ever generated in a run.
67    public Dictionary<int, SymbolString> ArchivedPhrases;     // Nodes in the search tree
68    SearchDataStore OpenPhrases;                              // Stack/Queue/etc. for fetching the next node in the search tree. 
69
70    public int EqualGeneratedSentences; // It is not guaranteed that shorter solutions are found first.
71                                        // When longer solutions are overwritten with shorter ones,
72                                        // this counter is increased.
73    public int Expansions;              // Number, how many times a nonterminal symbol is replaced with a production rule.
74    public Grammar Grammar;
75
76    #region ctors
77    public override IDeepCloneable Clone(Cloner cloner) {
78      return new GrammarEnumerationAlgorithm(this, cloner);
79    }
80
81    public GrammarEnumerationAlgorithm() {
82      var provider = new HeuristicLab.Problems.Instances.DataAnalysis.VariousInstanceProvider(seed: 1234);
83      var regProblem = provider.LoadData(provider.GetDataDescriptors().Single(x => x.Name.Contains("Poly-10")));
84
85      Problem = new RegressionProblem() {
86        ProblemData = regProblem
87      };
88
89      Parameters.Add(new ValueParameter<IntValue>(MaxTreeSizeParameterName, "The number of clusters.", new IntValue(6)));
90      Parameters.Add(new ValueParameter<IntValue>(GuiUpdateIntervalParameterName, "Number of generated sentences, until GUI is refreshed.", new IntValue(4000)));
91
92      Parameters.Add(new ValueParameter<EnumValue<StorageType>>(SearchDataStructureParameterName, new EnumValue<StorageType>(StorageType.RandomList)));
93    }
94
95    public GrammarEnumerationAlgorithm(GrammarEnumerationAlgorithm original, Cloner cloner) : base(original, cloner) { }
96    #endregion
97
98    protected override void Run(CancellationToken cancellationToken) {
99      #region init
100      InitResults();
101
102      AllSentences = new Dictionary<int, List<SymbolString>>();
103      ArchivedPhrases = new Dictionary<int, SymbolString>(); // Nodes in the search tree
104      DistinctSentences = new Dictionary<int, SymbolString>();
105      Expansions = 0;
106      EqualGeneratedSentences = 0;
107
108      Grammar = new Grammar(Problem.ProblemData.AllowedInputVariables.ToArray());
109
110      OpenPhrases = new SearchDataStore(SearchDataStructure); // Select search strategy
111      var phrase0 = new SymbolString(new[] { Grammar.StartSymbol });
112      #endregion
113
114      OpenPhrases.Store(Grammar.CalcHashCode(phrase0), phrase0);
115
116      while (OpenPhrases.Count > 0) {
117        if (cancellationToken.IsCancellationRequested) break;
118
119        StoredSymbolString fetchedPhrase = OpenPhrases.GetNext();
120        SymbolString currPhrase = fetchedPhrase.SymbolString;
121
122        ArchivedPhrases.Add(fetchedPhrase.Hash, currPhrase);
123
124        // expand next nonterminal symbols
125        int nonterminalSymbolIndex = currPhrase.FindIndex(s => s is NonterminalSymbol);
126        NonterminalSymbol expandedSymbol = currPhrase[nonterminalSymbolIndex] as NonterminalSymbol;
127
128        foreach (Production productionAlternative in expandedSymbol.Alternatives) {
129          SymbolString newPhrase = new SymbolString(currPhrase);
130          newPhrase.RemoveAt(nonterminalSymbolIndex);
131          newPhrase.InsertRange(nonterminalSymbolIndex, productionAlternative);
132
133          Expansions++;
134          if (newPhrase.Count <= MaxTreeSize) {
135            var phraseHash = Grammar.CalcHashCode(newPhrase);
136
137            if (newPhrase.IsSentence()) { // Sentence was generated.
138              SaveToAllSentences(phraseHash, newPhrase);
139
140              if (!DistinctSentences.ContainsKey(phraseHash) || DistinctSentences[phraseHash].Count > newPhrase.Count) {
141                if (DistinctSentences.ContainsKey(phraseHash)) EqualGeneratedSentences++; // for analysis only
142
143                DistinctSentences[phraseHash] = newPhrase;
144                EvaluateSentence(newPhrase);
145              }
146              UpdateView(AllSentences, DistinctSentences, Expansions);
147
148            } else if (!OpenPhrases.Contains(phraseHash) && !ArchivedPhrases.ContainsKey(phraseHash)) {
149              OpenPhrases.Store(phraseHash, newPhrase);
150            }
151          }
152        }
153      }
154
155      UpdateView(AllSentences, DistinctSentences, Expansions, force: true);
156      UpdateFinalResults();
157    }
158
159    // Store sentence to "MultiDictionary"
160    private void SaveToAllSentences(int hash, SymbolString sentence) {
161      if (AllSentences.ContainsKey(hash))
162        AllSentences[hash].Add(sentence);
163      else
164        AllSentences[hash] = new List<SymbolString> { sentence };
165    }
166
167    #region Evaluation of generated models.
168
169    // Evaluate sentence within an algorithm run.
170    private void EvaluateSentence(SymbolString symbolString) {
171      SymbolicExpressionTree tree = Grammar.ParseSymbolicExpressionTree(symbolString);
172      SymbolicRegressionModel model = new SymbolicRegressionModel(
173        Problem.ProblemData.TargetVariable,
174        tree,
175        new SymbolicDataAnalysisExpressionTreeLinearInterpreter());
176
177      var probData = Problem.ProblemData;
178      var target = probData.TargetVariableTrainingValues;
179      var estVals = model.GetEstimatedValues(probData.Dataset, probData.TrainingIndices);
180      OnlineCalculatorError error;
181      var r2 = OnlinePearsonsRSquaredCalculator.Calculate(target, estVals, out error);
182      if (error != OnlineCalculatorError.None) r2 = 0.0;
183
184      var bestR2 = ((DoubleValue)Results[BestTrainingQualityName].Value).Value;
185      if (r2 > bestR2) {
186        ((DoubleValue)Results[BestTrainingQualityName].Value).Value = r2;
187        BestTrainingSentence = symbolString;
188      }
189    }
190
191    #endregion
192
193    #region Visualization in HL
194    // Initialize entries in result set.
195    private void InitResults() {
196      BestTrainingSentence = null;
197
198      Results.Add(new Result(BestTrainingQualityName, new DoubleValue(-1.0)));
199
200      Results.Add(new Result(GeneratedSentencesName, new IntValue(0)));
201      Results.Add(new Result(DistinctSentencesName, new IntValue(0)));
202      Results.Add(new Result(PhraseExpansionsName, new IntValue(0)));
203      Results.Add(new Result(GeneratedEqualSentencesName, new IntValue(0)));
204      Results.Add(new Result(AverageTreeLengthName, new DoubleValue(1.0)));
205    }
206
207    // Update the view for intermediate results in an algorithm run.
208    private int updates;
209    private void UpdateView(Dictionary<int, List<SymbolString>> allGenerated,
210        Dictionary<int, SymbolString> distinctGenerated, int expansions, bool force = false) {
211      updates++;
212
213      if (force || updates % GuiUpdateInterval == 0) {
214        var allGeneratedEnum = allGenerated.Values.SelectMany(x => x).ToArray();
215        ((IntValue)Results[GeneratedSentencesName].Value).Value = allGeneratedEnum.Length;
216        ((IntValue)Results[DistinctSentencesName].Value).Value = distinctGenerated.Count;
217        ((IntValue)Results[PhraseExpansionsName].Value).Value = expansions;
218        ((IntValue)Results[GeneratedEqualSentencesName].Value).Value = EqualGeneratedSentences;
219        ((DoubleValue)Results[AverageTreeLengthName].Value).Value = allGeneratedEnum.Select(sentence => sentence.Count).Average();
220      }
221    }
222
223    // Generate all Results after an algorithm run.
224    private void UpdateFinalResults() {
225      SymbolicExpressionTree tree = Grammar.ParseSymbolicExpressionTree(BestTrainingSentence);
226      SymbolicRegressionModel model = new SymbolicRegressionModel(
227        Problem.ProblemData.TargetVariable,
228        tree,
229        new SymbolicDataAnalysisExpressionTreeLinearInterpreter());
230
231      IRegressionSolution bestTrainingSolution = new RegressionSolution(model, Problem.ProblemData);
232      Results.AddOrUpdateResult(BestTrainingSolutionName, bestTrainingSolution);
233
234      // Print generated sentences.
235      string[,] sentencesMatrix = new string[AllSentences.Values.SelectMany(x => x).Count(), 3];
236
237      int i = 0;
238      foreach (var sentenceSet in AllSentences) {
239        foreach (var sentence in sentenceSet.Value) {
240          sentencesMatrix[i, 0] = sentence.ToString();
241          sentencesMatrix[i, 1] = Grammar.PostfixToInfixParser(sentence).ToString();
242          sentencesMatrix[i, 2] = sentenceSet.Key.ToString();
243          i++;
244        }
245      }
246      Results.Add(new Result("All generated sentences", new StringMatrix(sentencesMatrix)));
247
248      string[,] distinctSentencesMatrix = new string[DistinctSentences.Count, 3];
249      i = 0;
250      foreach (KeyValuePair<int, SymbolString> distinctSentence in DistinctSentences) {
251        distinctSentencesMatrix[i, 0] = distinctSentence.Key.ToString();
252        distinctSentencesMatrix[i, 1] = Grammar.PostfixToInfixParser(distinctSentence.Value).ToString();
253        distinctSentencesMatrix[i, 2] = distinctSentence.Key.ToString();
254        i++;
255      }
256      Results.Add(new Result("Distinct generated sentences", new StringMatrix(distinctSentencesMatrix)));
257    }
258    #endregion
259 
260  }
261}
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