[15830] | 1 | #region License Information
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| 2 | /* HeuristicLab
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| 3 | * Copyright (C) 2002-2017 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 |
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| 27 | namespace HeuristicLab.Algorithms.DataAnalysis {
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| 28 | /// <summary>
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| 29 | /// Helper class for incremental split calculation.
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[16847] | 30 | /// Used while moving a potential splitter along the ordered training instances
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[15830] | 31 | /// </summary>
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[16847] | 32 | internal class CorreleationImpurityCalculator {
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[15830] | 33 | #region state
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| 34 | //Data
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| 35 | private readonly List<double> attributeValues;
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| 36 | private readonly List<double> targetValues;
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| 37 | private readonly double order;
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| 38 | private readonly UnivariateOnlineLR left;
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| 39 | private readonly UnivariateOnlineLR right;
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| 40 | #endregion
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| 41 |
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| 42 | #region Properties
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| 43 | public double Impurity { get; private set; }
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| 44 | public double SplitValue {
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| 45 | get {
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| 46 | if (left.Size <= 0) return double.NegativeInfinity;
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| 47 | if (left.Size >= attributeValues.Count) return double.PositiveInfinity;
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| 48 | return (attributeValues[left.Size - 1] + attributeValues[left.Size]) / 2;
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| 49 | }
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| 50 | }
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| 51 | public bool ValidPosition {
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| 52 | get { return !attributeValues[left.Size - 1].IsAlmost(attributeValues[left.Size]); }
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| 53 | }
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| 54 | public int LeftSize {
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| 55 | get { return left.Size; }
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| 56 | }
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| 57 | #endregion
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| 58 |
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| 59 | #region Constructors
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[16847] | 60 | public CorreleationImpurityCalculator(int partition, IEnumerable<double> atts, IEnumerable<double> targets, double order) {
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[15830] | 61 | if (order <= 0) throw new ArgumentException("Splitter order must be larger than 0");
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| 62 | this.order = order;
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| 63 | attributeValues = atts.ToList();
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| 64 | targetValues = targets.ToList();
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| 65 | left = new UnivariateOnlineLR(attributeValues.Take(partition).ToList(), targetValues.Take(partition).ToList());
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| 66 | right = new UnivariateOnlineLR(attributeValues.Skip(partition).ToList(), targetValues.Skip(partition).ToList());
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| 67 | UpdateImpurity();
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| 68 | }
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| 69 | #endregion
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| 70 |
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| 71 | #region IImpurityCalculator
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| 72 | public void Increment() {
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| 73 | var target = targetValues[left.Size];
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| 74 | var att = attributeValues[left.Size];
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| 75 | left.Add(att, target);
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| 76 | right.Remove(att, target);
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| 77 | UpdateImpurity();
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| 78 | }
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| 79 | #endregion
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| 80 |
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| 81 | private void UpdateImpurity() {
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| 82 | var yl = Math.Pow(left.Ssr, 1.0 / order);
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| 83 | var yr = Math.Pow(right.Ssr, 1.0 / order);
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| 84 | if (left.Size > 1 && right.Size > 1) Impurity = -yl - yr;
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| 85 | else Impurity = double.MinValue;
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| 86 | }
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| 87 | }
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| 88 | } |
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