#region License Information /* HeuristicLab * Copyright (C) 2002-2016 Heuristic and Evolutionary Algorithms Laboratory (HEAL) * * This file is part of HeuristicLab. * * HeuristicLab is free software: you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation, either version 3 of the License, or * (at your option) any later version. * * HeuristicLab is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with HeuristicLab. If not, see . */ #endregion using System; using System.Collections.Generic; using System.Linq; using System.Threading; using HeuristicLab.Common; using HeuristicLab.Core; using HeuristicLab.Data; using HeuristicLab.Encodings.SymbolicExpressionTreeEncoding; using HeuristicLab.Optimization; using HeuristicLab.Persistence.Default.CompositeSerializers.Storable; using HeuristicLab.Problems.DataAnalysis; using HeuristicLab.Problems.DataAnalysis.Symbolic; using HeuristicLab.Problems.DataAnalysis.Symbolic.Regression; namespace HeuristicLab.Algorithms.DataAnalysis { /// /// Linear regression data analysis algorithm. /// [Item("Linear Regression (LR)", "Linear regression data analysis algorithm (wrapper for ALGLIB).")] [Creatable(CreatableAttribute.Categories.DataAnalysisRegression, Priority = 100)] [StorableClass] public sealed class LinearRegression : FixedDataAnalysisAlgorithm { private const string LinearRegressionModelResultName = "Linear regression solution"; [StorableConstructor] private LinearRegression(bool deserializing) : base(deserializing) { } private LinearRegression(LinearRegression original, Cloner cloner) : base(original, cloner) { } public LinearRegression() : base() { Problem = new RegressionProblem(); } [StorableHook(HookType.AfterDeserialization)] private void AfterDeserialization() { } public override IDeepCloneable Clone(Cloner cloner) { return new LinearRegression(this, cloner); } #region linear regression protected override void Run(CancellationToken cancellationToken) { double rmsError, cvRmsError; var solution = CreateLinearRegressionSolution(Problem.ProblemData, out rmsError, out cvRmsError); Results.Add(new Result(LinearRegressionModelResultName, "The linear regression solution.", solution)); Results.Add(new Result("Root mean square error", "The root of the mean of squared errors of the linear regression solution on the training set.", new DoubleValue(rmsError))); Results.Add(new Result("Estimated root mean square error (cross-validation)", "The estimated root of the mean of squared errors of the linear regression solution via cross validation.", new DoubleValue(cvRmsError))); } public static ISymbolicRegressionSolution CreateLinearRegressionSolution(IRegressionProblemData problemData, out double rmsError, out double cvRmsError) { var dataset = problemData.Dataset; string targetVariable = problemData.TargetVariable; IEnumerable allowedInputVariables = problemData.AllowedInputVariables; IEnumerable rows = problemData.TrainingIndices; double[,] inputMatrix = AlglibUtil.PrepareInputMatrix(dataset, allowedInputVariables.Concat(new string[] { targetVariable }), rows); if (inputMatrix.Cast().Any(x => double.IsNaN(x) || double.IsInfinity(x))) throw new NotSupportedException("Linear regression does not support NaN or infinity values in the input dataset."); alglib.linearmodel lm = new alglib.linearmodel(); alglib.lrreport ar = new alglib.lrreport(); int nRows = inputMatrix.GetLength(0); int nFeatures = inputMatrix.GetLength(1) - 1; double[] coefficients = new double[nFeatures + 1]; // last coefficient is for the constant int retVal = 1; alglib.lrbuild(inputMatrix, nRows, nFeatures, out retVal, out lm, out ar); if (retVal != 1) throw new ArgumentException("Error in calculation of linear regression solution"); rmsError = ar.rmserror; cvRmsError = ar.cvrmserror; alglib.lrunpack(lm, out coefficients, out nFeatures); ISymbolicExpressionTree tree = new SymbolicExpressionTree(new ProgramRootSymbol().CreateTreeNode()); ISymbolicExpressionTreeNode startNode = new StartSymbol().CreateTreeNode(); tree.Root.AddSubtree(startNode); ISymbolicExpressionTreeNode addition = new Addition().CreateTreeNode(); startNode.AddSubtree(addition); int col = 0; foreach (string column in allowedInputVariables) { VariableTreeNode vNode = (VariableTreeNode)new HeuristicLab.Problems.DataAnalysis.Symbolic.Variable().CreateTreeNode(); vNode.VariableName = column; vNode.Weight = coefficients[col]; addition.AddSubtree(vNode); col++; } ConstantTreeNode cNode = (ConstantTreeNode)new Constant().CreateTreeNode(); cNode.Value = coefficients[coefficients.Length - 1]; addition.AddSubtree(cNode); SymbolicRegressionSolution solution = new SymbolicRegressionSolution(new SymbolicRegressionModel(problemData.TargetVariable, tree, new SymbolicDataAnalysisExpressionTreeLinearInterpreter()), (IRegressionProblemData)problemData.Clone()); solution.Model.Name = "Linear Regression Model"; solution.Name = "Linear Regression Solution"; return solution; } #endregion } }