Package org.aksw.palmetto.evaluate.correlation

Class PearsonsSampleCorrelationCoefficient

java.lang.Object

org.aksw.palmetto.evaluate.correlation.PearsonsSampleCorrelationCoefficient

All Implemented Interfaces:

RankCorrelationCalculator

public class PearsonsSampleCorrelationCoefficient
extends Object
implements RankCorrelationCalculator

Class implementing Pearsons sample correlation coefficient for two given, paired samples.

Author:

Michael Röder (michael.roeder@uni-paderborn.de)

Constructor Summary

Constructors

Constructor	Description
PearsonsSampleCorrelationCoefficient()

Method Summary

Modifier and Type	Method	Description
protected double[]	calculateCoVariances(double[] x, double avgX, double[] y, double avgY)	Calculates the variance and covariance for all valid (x,y) pairs.
protected double[]	calculatePairedAverage(double[] x, double[] y)	Calculates the average values of the given (x,y) pairs for all pairs that have x != NaN and y != NaN.
double	calculateRankCorrelation(double[] x, double[] y)	Calculates the Pearson sample correlation coefficient for the two given, paired samples.
protected int	countValidPairs(double[] x, double[] y)	Counts the number of valid pairs (x,y) , i.e., pairs where x != NaN and y != NaN.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

PearsonsSampleCorrelationCoefficient

public PearsonsSampleCorrelationCoefficient()

Method Detail

calculateRankCorrelation

public double calculateRankCorrelation(double[] x,
                                       double[] y)

Calculates the Pearson sample correlation coefficient for the two given, paired samples.

Specified by:

calculateRankCorrelation in interface RankCorrelationCalculator

Parameters:

x - the x samples

y - the y samples

Returns:

Parsons sample correlation coefficient

Throws:

IllegalArgumentException - if x and y have not the same size or have less than 2 elements.

countValidPairs

protected int countValidPairs(double[] x,
                              double[] y)

Counts the number of valid pairs (x,y) , i.e., pairs where x != NaN and y != NaN.

Parameters:

x - the x samples

y - the y samples

Returns:

the number of valid pairs

calculatePairedAverage

protected double[] calculatePairedAverage(double[] x,
                                          double[] y)

Calculates the average values of the given (x,y) pairs for all pairs that have x != NaN and y != NaN. The returned array contains the average x as first and the average y as second element.

Parameters:

x - the x samples

y - the y samples

Returns:

the averages of x and y.

calculateCoVariances

protected double[] calculateCoVariances(double[] x,
                                        double avgX,
                                        double[] y,
                                        double avgY)

Calculates the variance and covariance for all valid (x,y) pairs. The returned array contains the variance of x as first, the variance of y as second and their covariance as third element.

Parameters:

x - the x samples

y - the y samples

Returns:

the variances and covariance of x and y.