| 1 | #region License Information
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| 2 | /* HeuristicLab
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| 3 | * Copyright (C) 2002-2010 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.Linq;
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| 23 | using HeuristicLab.Common;
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| 24 | using HeuristicLab.Core;
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| 25 | using HeuristicLab.Data;
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| 26 | using HeuristicLab.Operators;
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| 27 | using HeuristicLab.Optimization;
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| 28 | using HeuristicLab.Parameters;
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| 29 | using HeuristicLab.Persistence.Default.CompositeSerializers.Storable;
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| 30 | using HeuristicLab.Encodings.SymbolicExpressionTreeEncoding;
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| 31 | using HeuristicLab.Problems.DataAnalysis.Evaluators;
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| 32 | using HeuristicLab.Problems.DataAnalysis.Symbolic;
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| 33 | using System.Collections.Generic;
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| 34 | using HeuristicLab.Analysis;
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| 35 |
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| 36 | using HeuristicLab.Problems.DataAnalysis.Symbolic.Symbols;
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| 37 |
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| 38 | namespace HeuristicLab.Problems.DataAnalysis.Regression.Symbolic {
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| 39 | /// <summary>
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| 40 | /// An operator for visualizing the best symbolic regression solution based on the validation set.
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| 41 | /// </summary>
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| 42 | [Item("BestSymbolicExpressionTreeVisualizer", "An operator for visualizing the best symbolic regression solution based on the validation set.")]
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| 43 | [StorableClass]
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| 44 | public sealed class BestValidationSymbolicRegressionSolutionVisualizer : SingleSuccessorOperator, ISingleObjectiveSolutionsVisualizer, ISolutionsVisualizer {
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| 45 | private const string SymbolicExpressionTreeInterpreterParameterName = "SymbolicExpressionTreeInterpreter";
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| 46 | private const string UpperEstimationLimitParameterName = "UpperEstimationLimit";
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| 47 | private const string LowerEstimationLimitParameterName = "LowerEstimationLimit";
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| 48 | private const string AlphaParameterName = "Alpha";
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| 49 | private const string BetaParameterName = "Beta";
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| 50 | private const string SymbolicRegressionModelParameterName = "SymbolicRegressionModel";
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| 51 | private const string DataAnalysisProblemDataParameterName = "DataAnalysisProblemData";
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| 52 | private const string BestValidationSolutionParameterName = "BestValidationSolution";
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| 53 | private const string ValidationSamplesStartParameterName = "ValidationSamplesStart";
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| 54 | private const string ValidationSamplesEndParameterName = "ValidationSamplesEnd";
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| 55 | private const string QualityParameterName = "Quality";
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| 56 | private const string ResultsParameterName = "Results";
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| 57 | private const string VariableFrequenciesParameterName = "VariableFrequencies";
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| 58 |
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| 59 | #region parameter properties
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| 60 | public ILookupParameter<ISymbolicExpressionTreeInterpreter> SymbolicExpressionTreeInterpreterParameter {
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| 61 | get { return (ILookupParameter<ISymbolicExpressionTreeInterpreter>)Parameters[SymbolicExpressionTreeInterpreterParameterName]; }
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| 62 | }
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| 63 | public IValueLookupParameter<DoubleValue> UpperEstimationLimitParameter {
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| 64 | get { return (IValueLookupParameter<DoubleValue>)Parameters[UpperEstimationLimitParameterName]; }
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| 65 | }
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| 66 | public IValueLookupParameter<DoubleValue> LowerEstimationLimitParameter {
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| 67 | get { return (IValueLookupParameter<DoubleValue>)Parameters[LowerEstimationLimitParameterName]; }
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| 68 | }
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| 69 | public IValueLookupParameter<IntValue> ValidationSamplesStartParameter {
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| 70 | get { return (IValueLookupParameter<IntValue>)Parameters[ValidationSamplesStartParameterName]; }
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| 71 | }
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| 72 | public IValueLookupParameter<IntValue> ValidationSamplesEndParameter {
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| 73 | get { return (IValueLookupParameter<IntValue>)Parameters[ValidationSamplesEndParameterName]; }
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| 74 | }
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| 75 |
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| 76 | public ILookupParameter<ItemArray<SymbolicExpressionTree>> SymbolicExpressionTreeParameter {
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| 77 | get { return (ILookupParameter<ItemArray<SymbolicExpressionTree>>)Parameters[SymbolicRegressionModelParameterName]; }
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| 78 | }
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| 79 | public ILookupParameter<ItemArray<DoubleValue>> AlphaParameter {
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| 80 | get { return (ILookupParameter<ItemArray<DoubleValue>>)Parameters[AlphaParameterName]; }
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| 81 | }
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| 82 | public ILookupParameter<ItemArray<DoubleValue>> BetaParameter {
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| 83 | get { return (ILookupParameter<ItemArray<DoubleValue>>)Parameters[BetaParameterName]; }
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| 84 | }
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| 85 | public ILookupParameter<DataAnalysisProblemData> DataAnalysisProblemDataParameter {
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| 86 | get { return (ILookupParameter<DataAnalysisProblemData>)Parameters[DataAnalysisProblemDataParameterName]; }
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| 87 | }
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| 88 | public ILookupParameter<SymbolicRegressionSolution> BestValidationSolutionParameter {
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| 89 | get { return (ILookupParameter<SymbolicRegressionSolution>)Parameters[BestValidationSolutionParameterName]; }
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| 90 | }
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| 91 | ILookupParameter ISolutionsVisualizer.VisualizationParameter {
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| 92 | get { return BestValidationSolutionParameter; }
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| 93 | }
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| 94 |
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| 95 | public ILookupParameter<ItemArray<DoubleValue>> QualityParameter {
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| 96 | get { return (ILookupParameter<ItemArray<DoubleValue>>)Parameters[QualityParameterName]; }
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| 97 | }
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| 98 |
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| 99 | public ILookupParameter<ResultCollection> ResultParameter {
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| 100 | get { return (ILookupParameter<ResultCollection>)Parameters[ResultsParameterName]; }
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| 101 | }
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| 102 | public ILookupParameter<DataTable> VariableFrequenciesParameter {
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| 103 | get { return (ILookupParameter<DataTable>)Parameters[VariableFrequenciesParameterName]; }
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| 104 | }
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| 105 |
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| 106 | #endregion
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| 107 |
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| 108 | #region properties
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| 109 | public ISymbolicExpressionTreeInterpreter SymbolicExpressionTreeInterpreter {
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| 110 | get { return SymbolicExpressionTreeInterpreterParameter.ActualValue; }
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| 111 | }
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| 112 | public DoubleValue UpperEstimationLimit {
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| 113 | get { return UpperEstimationLimitParameter.ActualValue; }
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| 114 | }
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| 115 | public DoubleValue LowerEstimationLimit {
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| 116 | get { return LowerEstimationLimitParameter.ActualValue; }
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| 117 | }
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| 118 | public IntValue ValidationSamplesStart {
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| 119 | get { return ValidationSamplesStartParameter.ActualValue; }
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| 120 | }
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| 121 | public IntValue ValidationSamplesEnd {
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| 122 | get { return ValidationSamplesEndParameter.ActualValue; }
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| 123 | }
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| 124 | public DataTable VariableFrequencies {
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| 125 | get { return VariableFrequenciesParameter.ActualValue; }
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| 126 | set { VariableFrequenciesParameter.ActualValue = value; }
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| 127 | }
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| 128 | #endregion
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| 129 |
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| 130 | public BestValidationSymbolicRegressionSolutionVisualizer()
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| 131 | : base() {
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| 132 | Parameters.Add(new SubScopesLookupParameter<SymbolicExpressionTree>(SymbolicRegressionModelParameterName, "The symbolic regression solutions from which the best solution should be visualized."));
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| 133 | Parameters.Add(new SubScopesLookupParameter<DoubleValue>(QualityParameterName, "The quality of the symbolic regression solutions."));
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| 134 | Parameters.Add(new LookupParameter<DataAnalysisProblemData>(DataAnalysisProblemDataParameterName, "The symbolic regression problme data on which the best solution should be evaluated."));
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| 135 | Parameters.Add(new LookupParameter<ISymbolicExpressionTreeInterpreter>(SymbolicExpressionTreeInterpreterParameterName, "The interpreter that should be used to calculate the output values of symbolic expression trees."));
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| 136 | Parameters.Add(new SubScopesLookupParameter<DoubleValue>(AlphaParameterName, "Alpha parameter for linear scaling of the estimated values."));
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| 137 | Parameters.Add(new SubScopesLookupParameter<DoubleValue>(BetaParameterName, "Beta parameter for linear scaling ot the estimated values."));
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| 138 | Parameters.Add(new ValueLookupParameter<DoubleValue>(UpperEstimationLimitParameterName, "The upper limit that should be used as cut off value for the output values of symbolic expression trees."));
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| 139 | Parameters.Add(new ValueLookupParameter<DoubleValue>(LowerEstimationLimitParameterName, "The lower limit that should be used as cut off value for the output values of symbolic expression trees."));
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| 140 | Parameters.Add(new ValueLookupParameter<IntValue>(ValidationSamplesStartParameterName, "The start index of the validation partition (part of the training partition)."));
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| 141 | Parameters.Add(new ValueLookupParameter<IntValue>(ValidationSamplesEndParameterName, "The end index of the validation partition (part of the training partition)."));
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| 142 | Parameters.Add(new LookupParameter<SymbolicRegressionSolution>(BestValidationSolutionParameterName, "The best symbolic expression tree based on the validation data for the symbolic regression problem."));
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| 143 | Parameters.Add(new LookupParameter<DataTable>(VariableFrequenciesParameterName, "The relative variable reference frequencies aggregated over the whole population."));
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| 144 | Parameters.Add(new LookupParameter<ResultCollection>(ResultsParameterName, "The result collection of the algorithm."));
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| 145 | }
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| 146 |
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| 147 | public override IOperation Apply() {
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| 148 | ItemArray<SymbolicExpressionTree> expressions = SymbolicExpressionTreeParameter.ActualValue;
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| 149 | ItemArray<DoubleValue> alphas = AlphaParameter.ActualValue;
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| 150 | ItemArray<DoubleValue> betas = BetaParameter.ActualValue;
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| 151 | var scaledExpressions = from i in Enumerable.Range(0, expressions.Count())
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| 152 | let expr = expressions[i]
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| 153 | let alpha = alphas[i] == null ? 0.0 : alphas[i].Value
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| 154 | let beta = betas[i] == null ? 1.0 : betas[i].Value
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| 155 | select new { Expression = expr, Alpha = alpha, Beta = beta };
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| 156 | DataAnalysisProblemData problemData = DataAnalysisProblemDataParameter.ActualValue;
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| 157 | #region update variable frequencies
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| 158 | var inputVariables = problemData.InputVariables.Select(x => x.Value);
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| 159 | if (VariableFrequencies == null) {
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| 160 | VariableFrequencies = new DataTable("Variable Frequencies", "Relative frequency of variable references aggregated over the whole population.");
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| 161 | AddResult("VariableFrequencies", VariableFrequencies);
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| 162 | // add a data row for each input variable
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| 163 | foreach (var inputVariable in inputVariables)
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| 164 | VariableFrequencies.Rows.Add(new DataRow(inputVariable));
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| 165 | }
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| 166 | foreach (var pair in VariableFrequencyAnalyser.CalculateVariableFrequencies(expressions, inputVariables)) {
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| 167 | VariableFrequencies.Rows[pair.Key].Values.Add(pair.Value);
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| 168 | }
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| 169 | #endregion
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| 170 |
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| 171 | #region determination of validation-best solution
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| 172 | int validationSamplesStart = ValidationSamplesStart.Value;
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| 173 | int validationSamplesEnd = ValidationSamplesEnd.Value;
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| 174 | var validationValues = problemData.Dataset.GetVariableValues(problemData.TargetVariable.Value, validationSamplesStart, validationSamplesEnd);
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| 175 | double upperEstimationLimit = UpperEstimationLimit.Value;
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| 176 | double lowerEstimationLimit = LowerEstimationLimit.Value;
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| 177 | var currentBestExpression = (from expression in scaledExpressions
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| 178 | let validationQuality =
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| 179 | SymbolicRegressionScaledMeanSquaredErrorEvaluator.CalculateWithScaling(
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| 180 | SymbolicExpressionTreeInterpreter, expression.Expression,
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| 181 | lowerEstimationLimit, upperEstimationLimit,
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| 182 | problemData.Dataset, problemData.TargetVariable.Value,
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| 183 | validationSamplesStart, validationSamplesEnd,
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| 184 | expression.Beta, expression.Alpha)
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| 185 | select new { Expression = expression, ValidationQuality = validationQuality })
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| 186 | .OrderBy(x => x.ValidationQuality)
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| 187 | .First();
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| 188 |
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| 189 | SymbolicRegressionSolution bestOfRunSolution = BestValidationSolutionParameter.ActualValue;
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| 190 | #endregion
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| 191 | #region update of validation-best solution
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| 192 | if (bestOfRunSolution == null) {
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| 193 | // no best of run solution yet -> make a solution from the currentBestExpression
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| 194 | UpdateBestOfRunSolution(problemData, currentBestExpression.Expression.Expression, SymbolicExpressionTreeInterpreter, lowerEstimationLimit, upperEstimationLimit, currentBestExpression.Expression.Alpha, currentBestExpression.Expression.Beta);
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| 195 | } else {
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| 196 | // compare quality of current best with best of run solution
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| 197 | var estimatedValidationValues = bestOfRunSolution.EstimatedValues.Skip(validationSamplesStart).Take(validationSamplesEnd - validationSamplesStart);
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| 198 | var bestOfRunValidationQuality = SimpleMSEEvaluator.Calculate(validationValues, estimatedValidationValues);
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| 199 | if (bestOfRunValidationQuality > currentBestExpression.ValidationQuality) {
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| 200 | UpdateBestOfRunSolution(problemData, currentBestExpression.Expression.Expression, SymbolicExpressionTreeInterpreter, lowerEstimationLimit, upperEstimationLimit, currentBestExpression.Expression.Alpha, currentBestExpression.Expression.Beta);
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| 201 | }
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| 202 | }
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| 203 | #endregion
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| 204 | return base.Apply();
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| 205 | }
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| 206 |
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| 207 | private void UpdateBestOfRunSolution(DataAnalysisProblemData problemData, SymbolicExpressionTree tree, ISymbolicExpressionTreeInterpreter interpreter,
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| 208 | double lowerEstimationLimit, double upperEstimationLimit,
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| 209 | double alpha, double beta) {
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| 210 | var newBestSolution = CreateDataAnalysisSolution(problemData, tree, interpreter, lowerEstimationLimit, upperEstimationLimit, alpha, beta);
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| 211 | if (BestValidationSolutionParameter.ActualValue == null)
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| 212 | BestValidationSolutionParameter.ActualValue = newBestSolution;
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| 213 | else
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| 214 | // only update model
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| 215 | BestValidationSolutionParameter.ActualValue.Model = newBestSolution.Model;
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| 216 |
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| 217 | AddResult("NumberOfInputVariables", new IntValue(CountInputVariables(tree)));
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| 218 |
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| 219 | var trainingValues = problemData.Dataset.GetVariableValues(problemData.TargetVariable.Value, problemData.TrainingSamplesStart.Value, problemData.TrainingSamplesEnd.Value);
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| 220 | var testValues = problemData.Dataset.GetVariableValues(problemData.TargetVariable.Value, problemData.TestSamplesStart.Value, problemData.TestSamplesEnd.Value);
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| 221 |
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| 222 | AddResult("MeanSquaredError (Training)", new DoubleValue(SimpleMSEEvaluator.Calculate(trainingValues, newBestSolution.EstimatedTrainingValues)));
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| 223 | AddResult("MeanRelativeError (Training)", new PercentValue(SimpleMeanAbsolutePercentageErrorEvaluator.Calculate(trainingValues, newBestSolution.EstimatedTrainingValues)));
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| 224 | AddResult("RSquared (Training)", new DoubleValue(SimpleRSquaredEvaluator.Calculate(trainingValues, newBestSolution.EstimatedTrainingValues)));
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| 225 |
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| 226 | AddResult("MeanSquaredError (Test)", new DoubleValue(SimpleMSEEvaluator.Calculate(testValues, newBestSolution.EstimatedTestValues)));
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| 227 | AddResult("MeanRelativeError (Test)", new PercentValue(SimpleMeanAbsolutePercentageErrorEvaluator.Calculate(testValues, newBestSolution.EstimatedTestValues)));
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| 228 | AddResult("RSquared (Test)", new DoubleValue(SimpleRSquaredEvaluator.Calculate(testValues, newBestSolution.EstimatedTestValues)));
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| 229 | }
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| 230 |
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| 231 | private int CountInputVariables(SymbolicExpressionTree tree) {
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| 232 | return (from node in tree.IterateNodesPrefix().OfType<VariableTreeNode>()
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| 233 | select node.VariableName)
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| 234 | .Distinct()
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| 235 | .Count();
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| 236 | }
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| 237 |
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| 238 | private void AddResult(string resultName, IItem value) {
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| 239 | var resultCollection = ResultParameter.ActualValue;
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| 240 | if (resultCollection.ContainsKey(resultName)) {
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| 241 | resultCollection[resultName].Value = value;
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| 242 | } else {
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| 243 | resultCollection.Add(new Result(resultName, value));
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| 244 | }
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| 245 | }
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| 246 |
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| 247 | private SymbolicRegressionSolution CreateDataAnalysisSolution(DataAnalysisProblemData problemData, SymbolicExpressionTree tree, ISymbolicExpressionTreeInterpreter interpreter,
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| 248 | double lowerEstimationLimit, double upperEstimationLimit,
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| 249 | double alpha, double beta) {
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| 250 | var mainBranch = tree.Root.SubTrees[0].SubTrees[0];
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| 251 | var scaledMainBranch = MakeSum(MakeProduct(beta, mainBranch), alpha);
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| 252 |
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| 253 | // remove the main branch before cloning to prevent cloning of sub-trees
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| 254 | tree.Root.SubTrees[0].RemoveSubTree(0);
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| 255 | var scaledTree = (SymbolicExpressionTree)tree.Clone();
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| 256 | // insert main branch into the original tree again
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| 257 | tree.Root.SubTrees[0].InsertSubTree(0, mainBranch);
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| 258 | // insert the scaled main branch into the cloned tree
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| 259 | scaledTree.Root.SubTrees[0].InsertSubTree(0, scaledMainBranch);
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| 260 | // create a new solution using the scaled tree
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| 261 | var model = new SymbolicRegressionModel(interpreter, scaledTree, problemData.InputVariables.Select(s => s.Value));
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| 262 | return new SymbolicRegressionSolution(problemData, model, lowerEstimationLimit, upperEstimationLimit);
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| 263 | }
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| 264 |
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| 265 | private SymbolicExpressionTreeNode MakeSum(SymbolicExpressionTreeNode treeNode, double alpha) {
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| 266 | var node = (new Addition()).CreateTreeNode();
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| 267 | var alphaConst = MakeConstant(alpha);
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| 268 | node.AddSubTree(treeNode);
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| 269 | node.AddSubTree(alphaConst);
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| 270 | return node;
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| 271 | }
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| 272 |
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| 273 | private SymbolicExpressionTreeNode MakeProduct(double beta, SymbolicExpressionTreeNode treeNode) {
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| 274 | var node = (new Multiplication()).CreateTreeNode();
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| 275 | var betaConst = MakeConstant(beta);
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| 276 | node.AddSubTree(treeNode);
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| 277 | node.AddSubTree(betaConst);
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| 278 | return node;
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| 279 | }
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| 280 |
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| 281 | private SymbolicExpressionTreeNode MakeConstant(double c) {
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| 282 | var node = (ConstantTreeNode)(new Constant()).CreateTreeNode();
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| 283 | node.Value = c;
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| 284 | return node;
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| 285 | }
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| 286 | }
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| 287 | }
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