java.lang.Object

ch.idsia.utils.statistics.Stats

public class Stats
extends java.lang.Object

This class implements some simple statistical functions on arrays of numbers, namely, the mean, variance, standard deviation, covariance, min and max.

Constructor Summary

Constructors

Constructor Description

Stats()

Method Summary

Modifier and Type	Method	Description
`static void`	`analyse(double[] v)`	Prints the means and standard deviation of the data to the standard output.
`static void`	`analyse(double[] v, java.io.PrintStream s)`	Prints the means and standard deviation of the data to the specified PrintStream
`static java.lang.String`	`analysisString(double[] v)`
`static double`	`correlation(double[] v1, double[] v2)`
`static double`	`correlation2(double[] v1, double[] v2)`
`static double`	`covar(double[] v1, double[] v2)`	Returns the covariance of the paired arrays of double.
`static void`	`main(java.lang.String[] args)`	Runs through some utils using the functions defined in this class.
`static double`	`max(double[] v)`	Returns the maximum value in the array.
`static double`	`mean(double[] v)`	Returns the average of an array of double.
`static double`	`mean(int[] v)`
`static double`	`min(double[] v)`	Returns the minimum value in the array.
`static java.lang.String`	`rmsString(double[] v)`	Returns a string that compares the root mean square of the data with the standard deviation of the data.
`static double`	`sdev(double[] v)`	Returns the sample standard deviation of an array of double.
`static double`	`sqr(double x)`	Calculates the square of a double.
`static double`	`stderr(double[] v)`	Returns the standard error of an array of double, where this is defined as the standard deviation of the sample divided by the square root of the sample size.
`static double[]`	`v2a(java.util.Vector<java.lang.Number> v)`	Converts a vector of Numbers into an array of double.
`static double`	`variance(double[] v)`	Returns the variance of the array of double.
`static double`	`variance2(double[] v)`	this alternative version was used to check correctness

Methods inherited from class java.lang.Object

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

Constructor Details
- Stats
  
  public Stats()
Method Details
- v2a
  
  public static double[] v2a(java.util.Vector<java.lang.Number> v)
  
  Converts a vector of Numbers into an array of double. This function does not necessarily belong here, but is commonly required in order to apply the statistical functions conveniently, since they only deal with arrays of double. (Note that a Number of the common superclass of all the Object versions of the primitives, such as Integer, Double etc.).
- sqr
  
  public static double sqr(double x)
  
  Calculates the square of a double.
  
  Returns:
  
  Returns x*x
- mean
  
  public static double mean(double[] v)
  
  Returns the average of an array of double.
- mean
  
  public static double mean(int[] v)
  
  Parameters:
  
  v - - sample
  
  Returns:
  
  the average of an array of int.
- sdev
  
  public static double sdev(double[] v)
  
  Returns the sample standard deviation of an array of double.
- stderr
  
  public static double stderr(double[] v)
  
  Returns the standard error of an array of double, where this is defined as the standard deviation of the sample divided by the square root of the sample size.
- variance
  
  public static double variance(double[] v)
  
  Returns the variance of the array of double.
- variance2
  
  public static double variance2(double[] v)
  
  this alternative version was used to check correctness
- covar
  
  public static double covar(double[] v1, double[] v2)
  
  Returns the covariance of the paired arrays of double.
- correlation
  
  public static double correlation(double[] v1, double[] v2)
- correlation2
  
  public static double correlation2(double[] v1, double[] v2)
- max
  
  public static double max(double[] v)
  
  Returns the maximum value in the array.
- min
  
  public static double min(double[] v)
  
  Returns the minimum value in the array.
- analyse
  
  public static void analyse(double[] v)
  
  Prints the means and standard deviation of the data to the standard output.
- analyse
  
  public static void analyse(double[] v, java.io.PrintStream s)
  
  Prints the means and standard deviation of the data to the specified PrintStream
  
  Parameters:
  
  v - contains the data
  
  s - is the corresponding PrintStream
- analysisString
  
  public static java.lang.String analysisString(double[] v)
  
  Parameters:
  
  v - contains the data
  
  Returns:
  
  A String summary of the with the mean and standard deviation of the data.
- rmsString
  
  public static java.lang.String rmsString(double[] v)
  
  Returns a string that compares the root mean square of the data with the standard deviation of the data. This is probably too specialised to be of much general use.
  
  Parameters:
  
  v - contains the data
  
  Returns:
  
  root mean square = <...> standard deviation = <...>
- main
  
  public static void main(java.lang.String[] args) throws java.io.IOException
  
  Runs through some utils using the functions defined in this class.
  
  Throws:
  
  java.io.IOException

Class Stats

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Constructor Details

Method Details