[7154] | 1 | #region License Information
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| 2 | /* HeuristicLab
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[16453] | 3 | * Copyright (C) 2002-2019 Heuristic and Evolutionary Algorithms Laboratory (HEAL)
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[7154] | 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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[14843] | 22 | using System;
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[7154] | 23 | using System.Collections.Generic;
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[14843] | 24 | using System.Linq;
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[7154] | 25 |
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| 26 | namespace HeuristicLab.Problems.DataAnalysis {
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| 27 | public static class DatasetExtensions {
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[14843] | 28 | public static double[,] ToArray(this IDataset dataset, IEnumerable<string> variables, IEnumerable<int> rows) {
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| 29 | return ToArray(dataset,
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| 30 | variables,
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| 31 | transformations: variables.Select(_ => (ITransformation<double>)null), // no transform
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| 32 | rows: rows);
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| 33 | }
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| 34 | public static double[,] ToArray(this IDataset dataset, IEnumerable<string> variables,
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| 35 | IEnumerable<ITransformation<double>> transformations, IEnumerable<int> rows) {
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| 36 | string[] variablesArr = variables.ToArray();
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| 37 | int[] rowsArr = rows.ToArray();
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| 38 | ITransformation<double>[] transformArr = transformations.ToArray();
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| 39 | if (transformArr.Length != variablesArr.Length)
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| 40 | throw new ArgumentException("Number of variables and number of transformations must match.");
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| 41 |
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| 42 | double[,] matrix = new double[rowsArr.Length, variablesArr.Length];
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| 43 |
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| 44 | for (int i = 0; i < variablesArr.Length; i++) {
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| 45 | var origValues = dataset.GetDoubleValues(variablesArr[i], rowsArr);
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| 46 | var values = transformArr[i] != null ? transformArr[i].Apply(origValues) : origValues;
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| 47 | int row = 0;
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| 48 | foreach (var value in values) {
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| 49 | matrix[row, i] = value;
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| 50 | row++;
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| 51 | }
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[7154] | 52 | }
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[14843] | 53 |
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| 54 | return matrix;
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[7154] | 55 | }
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[14843] | 56 |
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| 57 | /// <summary>
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| 58 | /// Prepares a binary data matrix from a number of factors and specified factor values
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| 59 | /// </summary>
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| 60 | /// <param name="dataset">A dataset that contains the variable values</param>
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| 61 | /// <param name="factorVariables">An enumerable of categorical variables (factors). For each variable an enumerable of values must be specified.</param>
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| 62 | /// <param name="rows">An enumerable of row indices for the dataset</param>
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| 63 | /// <returns></returns>
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| 64 | /// <remarks>Factor variables (categorical variables) are split up into multiple binary variables one for each specified value.</remarks>
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| 65 | public static double[,] ToArray(
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| 66 | this IDataset dataset,
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| 67 | IEnumerable<KeyValuePair<string, IEnumerable<string>>> factorVariables,
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| 68 | IEnumerable<int> rows) {
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| 69 | // check input variables. Only string variables are allowed.
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| 70 | var invalidInputs =
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| 71 | factorVariables.Select(kvp => kvp.Key).Where(name => !dataset.VariableHasType<string>(name));
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| 72 | if (invalidInputs.Any())
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| 73 | throw new NotSupportedException("Unsupported inputs: " + string.Join(", ", invalidInputs));
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| 74 |
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| 75 | int numBinaryColumns = factorVariables.Sum(kvp => kvp.Value.Count());
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| 76 |
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| 77 | List<int> rowsList = rows.ToList();
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| 78 | double[,] matrix = new double[rowsList.Count, numBinaryColumns];
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| 79 |
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| 80 | int col = 0;
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| 81 | foreach (var kvp in factorVariables) {
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| 82 | var varName = kvp.Key;
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| 83 | var cats = kvp.Value;
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| 84 | if (!cats.Any()) continue;
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| 85 | foreach (var cat in cats) {
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| 86 | var values = dataset.GetStringValues(varName, rows);
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| 87 | int row = 0;
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| 88 | foreach (var value in values) {
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| 89 | matrix[row, col] = value == cat ? 1 : 0;
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| 90 | row++;
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| 91 | }
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| 92 | col++;
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| 93 | }
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| 94 | }
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| 95 | return matrix;
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| 96 | }
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| 97 |
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| 98 | public static IEnumerable<KeyValuePair<string, IEnumerable<string>>> GetFactorVariableValues(
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| 99 | this IDataset ds, IEnumerable<string> factorVariables, IEnumerable<int> rows) {
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| 100 | return from factor in factorVariables
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| 101 | let distinctValues = ds.GetStringValues(factor, rows).Distinct().ToArray()
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| 102 | // 1 distinct value => skip (constant)
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| 103 | // 2 distinct values => only take one of the two values
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| 104 | // >=3 distinct values => create a binary value for each value
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| 105 | let reducedValues = distinctValues.Length <= 2
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| 106 | ? distinctValues.Take(distinctValues.Length - 1)
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| 107 | : distinctValues
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| 108 | select new KeyValuePair<string, IEnumerable<string>>(factor, reducedValues);
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| 109 | }
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[7154] | 110 | }
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| 111 | }
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