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source: branches/3044_variableScaling/HeuristicLab.Problems.DataAnalysis/3.4/Implementation/Transformations/LogarithmicTransformation.cs @ 17390

Last change on this file since 17390 was 16565, checked in by gkronber, 6 years ago

#2520: merged changes from PersistenceOverhaul branch (r16451:16564) into trunk

File size: 2.1 KB
Line 
1using System;
2using System.Collections.Generic;
3using System.Linq;
4using HeuristicLab.Common;
5using HeuristicLab.Core;
6using HeuristicLab.Data;
7using HeuristicLab.Parameters;
8using HEAL.Attic;
9
10namespace HeuristicLab.Problems.DataAnalysis {
11  [StorableType("D3330C77-060A-4F75-A0C5-47AC81C5F2DF")]
12  [Item("Logarithmic Transformation", "f(x) = log(x, b) | Represents a logarithmic transformation.")]
13  public class LogarithmicTransformation : Transformation<double> {
14    protected const string BaseParameterName = "Base";
15
16    #region Parameters
17    public IValueParameter<DoubleValue> BaseParameter {
18      get { return (IValueParameter<DoubleValue>)Parameters[BaseParameterName]; }
19    }
20    #endregion
21
22    #region properties
23    public override string ShortName {
24      get { return "Log"; }
25    }
26    public double Base {
27      get { return BaseParameter.Value.Value; }
28    }
29    #endregion
30
31    [StorableConstructor]
32    protected LogarithmicTransformation(StorableConstructorFlag _) : base(_) { }
33    protected LogarithmicTransformation(LogarithmicTransformation original, Cloner cloner)
34      : base(original, cloner) {
35    }
36    public LogarithmicTransformation(IEnumerable<string> allowedColumns)
37      : base(allowedColumns) {
38      Parameters.Add(new ValueParameter<DoubleValue>(BaseParameterName, "b | Base of log-function", new DoubleValue(Math.E)));
39    }
40
41    public override IDeepCloneable Clone(Cloner cloner) {
42      return new LogarithmicTransformation(this, cloner);
43    }
44
45    public override IEnumerable<double> Apply(IEnumerable<double> data) {
46      var b = Base;
47      return data.Select(d => d > 0.0 ? Math.Log(d, b) : d);
48    }
49
50    public override bool Check(IEnumerable<double> data, out string errorMsg) {
51      errorMsg = null;
52      int errorCounter = data.Count(i => i <= 0.0);
53      if (errorCounter > 0) {
54        errorMsg = String.Format("{0} values are zero or below zero. Logarithm can not be applied onto these values", errorCounter);
55        return false;
56      }
57      return true;
58    }
59
60  }
61}
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