diff --git a/src/Numerics/Statistics/Correlation.cs b/src/Numerics/Statistics/Correlation.cs
index 11566965..1faf845f 100644
--- a/src/Numerics/Statistics/Correlation.cs
+++ b/src/Numerics/Statistics/Correlation.cs
@@ -4,7 +4,7 @@
// http://github.com/mathnet/mathnet-numerics
// http://mathnetnumerics.codeplex.com
//
-// Copyright (c) 2009-2010 Math.NET
+// Copyright (c) 2009-2013 Math.NET
//
// Permission is hereby granted, free of charge, to any person
// obtaining a copy of this software and associated documentation
@@ -28,19 +28,21 @@
// OTHER DEALINGS IN THE SOFTWARE.
//
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using MathNet.Numerics.LinearAlgebra;
+using MathNet.Numerics.Properties;
+
namespace MathNet.Numerics.Statistics
{
- using System;
- using System.Collections.Generic;
- using System.Linq;
-
///
/// A class with correlation measures between two datasets.
///
public static class Correlation
{
///
- /// Computes the Pearson product-moment correlation coefficient.
+ /// Computes the Pearson Product-Moment Correlation coefficient.
///
/// Sample data A.
/// Sample data B.
@@ -62,7 +64,7 @@ namespace MathNet.Numerics.Statistics
{
if (!ieB.MoveNext())
{
- throw new ArgumentOutOfRangeException("dataB", "Datasets dataA and dataB need to have the same length. dataB is shorter.");
+ throw new ArgumentOutOfRangeException("dataB", Resources.ArgumentArraysSameLength);
}
double currentA = ieA.Current;
double currentB = ieB.Current;
@@ -82,7 +84,7 @@ namespace MathNet.Numerics.Statistics
}
if (ieB.MoveNext())
{
- throw new ArgumentOutOfRangeException("dataA", "Datasets dataA and dataB need to have the same length. dataA is shorter.");
+ throw new ArgumentOutOfRangeException("dataA", Resources.ArgumentArraysSameLength);
}
}
@@ -90,24 +92,78 @@ namespace MathNet.Numerics.Statistics
}
///
- /// Computes the Spearman Ranked Correlation Coefficient.
+ /// Computes the Pearson Product-Moment Correlation matrix.
+ ///
+ /// Array of sample data vectors.
+ /// The Pearson product-moment correlation matrix.
+ public static Matrix PearsonMatrix(params double[][] vectors)
+ {
+ var m = Matrix.Build.DenseIdentity(vectors.Length);
+ for (int i = 0; i < vectors.Length; i++)
+ for (int j = i + 1; j < vectors.Length; j++)
+ {
+ var c = Pearson(vectors[i], vectors[j]);
+ m.At(i, j, c);
+ m.At(j, i, c);
+ }
+ return m;
+ }
+
+ ///
+ /// Computes the Pearson Product-Moment Correlation matrix.
+ ///
+ /// Enumerable of sample data vectors.
+ /// The Pearson product-moment correlation matrix.
+ public static Matrix PearsonMatrix(IEnumerable vectors)
+ {
+ return PearsonMatrix(vectors as double[][] ?? vectors.ToArray());
+ }
+
+ ///
+ /// Computes the Spearman Ranked Correlation coefficient.
///
/// Sample data series A.
/// Sample data series B.
- /// The Spearman Ranked Correlation Coefficient.
+ /// The Spearman ranked correlation coefficient.
public static double Spearman(IEnumerable dataA, IEnumerable dataB)
{
- return Pearson(RankedSeries(dataA.ToList()), RankedSeries(dataB.ToList()));
+ return Pearson(Rank(dataA), Rank(dataB));
+ }
+
+ ///
+ /// Computes the Spearman Ranked Correlation matrix.
+ ///
+ /// Array of sample data vectors.
+ /// The Spearman ranked correlation matrix.
+ public static Matrix SpearmanMatrix(params double[][] vectors)
+ {
+ return PearsonMatrix(vectors.Select(Rank).ToArray());
}
- private static IEnumerable RankedSeries(ICollection series)
+ ///
+ /// Computes the Spearman Ranked Correlation matrix.
+ ///
+ /// Enumerable of sample data vectors.
+ /// The Spearman ranked correlation matrix.
+ public static Matrix SpearmanMatrix(IEnumerable vectors)
{
- if (series == null || series.Count == 0)
- return Enumerable.Empty();
+ return PearsonMatrix(vectors.Select(Rank).ToArray());
+ }
- var rankedSamples = series.Select((sample, index) => new { Sample = sample, RankIndex = index }).OrderBy(s => s.Sample).ToList();
+ private static double[] Rank(IEnumerable series)
+ {
+ if (series == null)
+ {
+ return new double[0];
+ }
- var rankedArray = new double[series.Count];
+ var rankedSamples = series.Select((sample, index) => new {Sample = sample, RankIndex = index}).OrderBy(s => s.Sample).ToArray();
+ if (rankedSamples.Length == 0)
+ {
+ return new double[0];
+ }
+
+ var rankedArray = new double[rankedSamples.Length];
var previousSample = rankedSamples.Select((sampleIndex, index) => new { SampleIndex = sampleIndex, LoopIndex = index }).First();
foreach (var rankedSampleIndex in rankedSamples.Select((sampleIndex, index) => new { SampleIndex = sampleIndex, LoopIndex = index }))
@@ -115,18 +171,24 @@ namespace MathNet.Numerics.Statistics
var currentSample = rankedSampleIndex;
if (Math.Abs(currentSample.SampleIndex.Sample - previousSample.SampleIndex.Sample) <= 0)
+ {
continue;
+ }
var rankedValue = (currentSample.LoopIndex + previousSample.LoopIndex - 1) / 2d + 1;
foreach (var index in Enumerable.Range(previousSample.LoopIndex, currentSample.LoopIndex - previousSample.LoopIndex))
+ {
rankedArray[rankedSamples[index].RankIndex] = rankedValue;
+ }
previousSample = currentSample;
}
- var finalValue = (rankedSamples.Count + previousSample.LoopIndex - 1) / 2d + 1;
- foreach (var index in Enumerable.Range(previousSample.LoopIndex, rankedSamples.Count - previousSample.LoopIndex))
+ var finalValue = (rankedSamples.Length + previousSample.LoopIndex - 1) / 2d + 1;
+ foreach (var index in Enumerable.Range(previousSample.LoopIndex, rankedSamples.Length - previousSample.LoopIndex))
+ {
rankedArray[rankedSamples[index].RankIndex] = finalValue;
+ }
return rankedArray;
}