[6567] | 1 | #region License Information
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| 2 | /* HeuristicLab
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| 3 | * Copyright (C) 2002-2011 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 HeuristicLab.Common;
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| 26 | using HeuristicLab.Core;
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| 27 | using HeuristicLab.Data;
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| 28 | using HeuristicLab.Encodings.SymbolicExpressionTreeEncoding;
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| 29 | using HeuristicLab.Optimization;
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| 30 | using HeuristicLab.Persistence.Default.CompositeSerializers.Storable;
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| 31 | using HeuristicLab.Problems.DataAnalysis;
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| 32 | using HeuristicLab.Problems.DataAnalysis.Symbolic;
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| 33 | using HeuristicLab.Problems.DataAnalysis.Symbolic.Regression;
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| 34 |
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| 35 | namespace HeuristicLab.Algorithms.DataAnalysis {
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| 36 | /// <summary>
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| 37 | /// Multinomial logit regression data analysis algorithm.
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| 38 | /// </summary>
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| 39 | [Item("Multinomial logit classification", "Multinomial logit classification data analysis algorithm (wrapper for ALGLIB).")]
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| 40 | [Creatable("Data Analysis")]
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| 41 | [StorableClass]
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| 42 | public sealed class MultiNomialLogitClassification : FixedDataAnalysisAlgorithm<IClassificationProblem> {
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| 43 | private const string LogitClassificationModelResultName = "Logit classification solution";
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| 44 |
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| 45 | [StorableConstructor]
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| 46 | private MultiNomialLogitClassification(bool deserializing) : base(deserializing) { }
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| 47 | private MultiNomialLogitClassification(MultiNomialLogitClassification original, Cloner cloner)
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| 48 | : base(original, cloner) {
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| 49 | }
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| 50 | public MultiNomialLogitClassification()
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| 51 | : base() {
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| 52 | Problem = new ClassificationProblem();
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| 53 | }
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| 54 | [StorableHook(HookType.AfterDeserialization)]
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| 55 | private void AfterDeserialization() { }
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| 56 |
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| 57 | public override IDeepCloneable Clone(Cloner cloner) {
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| 58 | return new MultiNomialLogitClassification(this, cloner);
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| 59 | }
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| 60 |
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| 61 | #region logit regression
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| 62 | protected override void Run() {
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| 63 | double rmsError, relClassError;
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| 64 | var solution = CreateLogitClassificationSolution(Problem.ProblemData, out rmsError, out relClassError);
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| 65 | Results.Add(new Result(LogitClassificationModelResultName, "The linear regression solution.", solution));
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| 66 | Results.Add(new Result("Root mean square error", "The root of the mean of squared errors of the logit regression solution on the training set.", new DoubleValue(rmsError)));
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| 67 | Results.Add(new Result("Relative classification error", "Relative classification error on the training set (percentage of misclassified cases).", new PercentValue(relClassError)));
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| 68 | }
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| 69 |
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| 70 | public static IClassificationSolution CreateLogitClassificationSolution(IClassificationProblemData problemData, out double rmsError, out double relClassError) {
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| 71 | Dataset dataset = problemData.Dataset;
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| 72 | string targetVariable = problemData.TargetVariable;
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| 73 | IEnumerable<string> allowedInputVariables = problemData.AllowedInputVariables;
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| 74 | IEnumerable<int> rows = problemData.TrainingIndizes;
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| 75 | double[,] inputMatrix = AlglibUtil.PrepareInputMatrix(dataset, allowedInputVariables.Concat(new string[] { targetVariable }), rows);
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| 76 | if (inputMatrix.Cast<double>().Any(x => double.IsNaN(x) || double.IsInfinity(x)))
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| 77 | throw new NotSupportedException("Multinomial logit classification does not support NaN or infinity values in the input dataset.");
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| 78 |
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| 79 | alglib.logitmodel lm = new alglib.logitmodel();
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| 80 | alglib.mnlreport rep = new alglib.mnlreport();
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| 81 | int nRows = inputMatrix.GetLength(0);
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| 82 | int nFeatures = inputMatrix.GetLength(1) - 1;
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| 83 | double[] classValues = dataset.GetVariableValues(targetVariable).Distinct().OrderBy(x => x).ToArray();
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| 84 | int nClasses = classValues.Count();
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| 85 | // map original class values to values [0..nClasses-1]
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| 86 | Dictionary<double, double> classIndizes = new Dictionary<double, double>();
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| 87 | for (int i = 0; i < nClasses; i++) {
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| 88 | classIndizes[classValues[i]] = i;
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| 89 | }
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| 90 | for (int row = 0; row < nRows; row++) {
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| 91 | inputMatrix[row, nFeatures] = classIndizes[inputMatrix[row, nFeatures]];
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| 92 | }
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| 93 | int info;
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| 94 | alglib.mnltrainh(inputMatrix, nRows, nFeatures, nClasses, out info, out lm, out rep);
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| 95 | if (info != 1) throw new ArgumentException("Error in calculation of logit classification solution");
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| 96 |
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| 97 | rmsError = alglib.mnlrmserror(lm, inputMatrix, nRows);
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| 98 | relClassError = alglib.mnlrelclserror(lm, inputMatrix, nRows);
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| 99 |
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| 100 | LogitClassificationSolution solution = new LogitClassificationSolution(problemData, new LogitModel(lm, targetVariable, allowedInputVariables, classValues));
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| 101 | return solution;
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| 102 | }
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| 103 | #endregion
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| 104 | }
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| 105 | }
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