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source: trunk/sources/HeuristicLab.Algorithms.DataAnalysis/3.4/TSNE/Distances/CosineDistance.cs @ 15234

Last change on this file since 15234 was 15234, checked in by abeham, 5 years ago

#2700: fixed some typos

File size: 2.7 KB
Line 
1#region License Information
2/* HeuristicLab
3 * Copyright (C) 2002-2016 Heuristic and Evolutionary Algorithms Laboratory (HEAL)
4 *
5 * This file is part of HeuristicLab.
6 *
7 * HeuristicLab is free software: you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation, either version 3 of the License, or
10 * (at your option) any later version.
11 *
12 * HeuristicLab is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15 * GNU General Public License for more details.
16 *
17 * You should have received a copy of the GNU General Public License
18 * along with HeuristicLab. If not, see <http://www.gnu.org/licenses/>.
19 */
20#endregion
21
22using System;
23using System.Collections.Generic;
24using System.Linq;
25using HeuristicLab.Common;
26using HeuristicLab.Core;
27using HeuristicLab.Persistence.Default.CompositeSerializers.Storable;
28
29namespace HeuristicLab.Algorithms.DataAnalysis {
30
31  /// <summary>
32  /// The angular distance as defined as a normalized distance measure dependent on the angle between two vectors.
33  /// </summary>
34  [StorableClass]
35  [Item("CosineDistance", "The angular distance as defined as a normalized distance measure dependent on the angle between two vectors.")]
36  public class CosineDistance : DistanceBase<IEnumerable<double>> {
37
38    #region HLConstructors & Cloning
39    [StorableConstructor]
40    protected CosineDistance(bool deserializing) : base(deserializing) { }
41    protected CosineDistance(CosineDistance original, Cloner cloner)
42      : base(original, cloner) { }
43    public CosineDistance() { }
44    public override IDeepCloneable Clone(Cloner cloner) {
45      return new CosineDistance(this, cloner);
46    }
47    #endregion
48
49    #region statics
50    public static double GetDistance(IReadOnlyList<double> point1, IReadOnlyList<double> point2) {
51      if (point1.Count != point2.Count) throw new ArgumentException("Cosine distance not defined on vectors of different length");
52      var innerprod = 0.0;
53      var length1 = 0.0;
54      var length2 = 0.0;
55
56      for (var i = 0; i < point1.Count; i++) {
57        double d1 = point1[i], d2 = point2[i];
58        innerprod += d1 * d2;
59        length1 += d1 * d1;
60        length2 += d2 * d2;
61      }
62      var l = Math.Sqrt(length1 * length2);
63      if (l.IsAlmost(0)) throw new ArgumentException("Cosine distance is not defined on vectors of length 0");
64      return 1 - innerprod / l;
65    }
66    #endregion
67    public override double Get(IEnumerable<double> a, IEnumerable<double> b) {
68      return GetDistance(a.ToArray(), b.ToArray());
69    }
70  }
71}
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