weka.experiment

Class Stats

java.lang.Object

weka.experiment.Stats

All Implemented Interfaces:

Serializable, RevisionHandler

public class Stats
extends Object
implements Serializable, RevisionHandler

A class to store simple statistics

Version:

$Revision: 8034 $

Author:

Len Trigg (trigg@cs.waikato.ac.nz)

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field and Description
double	count The number of values seen
double	max The maximum value seen, or Double.NaN if no values seen
double	mean The mean of values at the last calculateDerived() call
double	min The minimum value seen, or Double.NaN if no values seen
double	stdDev The std deviation of values at the last calculateDerived() call
double	sum The sum of values seen
double	sumSq The sum of values squared seen

Constructor Summary

Constructors

Constructor and Description
Stats()

Method Summary

Methods

Modifier and Type	Method and Description
void	add(double value) Adds a value to the observed values
void	add(double value, double n) Adds a value that has been seen n times to the observed values
void	calculateDerived() Tells the object to calculate any statistics that don't have their values automatically updated during add.
String	getRevision() Returns the revision string.
static void	main(String[] args) Tests the paired stats object from the command line.
void	subtract(double value) Removes a value to the observed values (no checking is done that the value being removed was actually added).
void	subtract(double value, double n) Subtracts a value that has been seen n times from the observed values
String	toString() Returns a string summarising the stats so far.

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

count

public double count

The number of values seen

sum

public double sum

The sum of values seen

sumSq

public double sumSq

The sum of values squared seen

stdDev

public double stdDev

The std deviation of values at the last calculateDerived() call

mean

public double mean

The mean of values at the last calculateDerived() call

min

public double min

The minimum value seen, or Double.NaN if no values seen

max

public double max

The maximum value seen, or Double.NaN if no values seen

Constructor Detail

Stats

public Stats()

Method Detail

add

public void add(double value)

Adds a value to the observed values

Parameters:

value - the observed value

add

public void add(double value,
       double n)

Adds a value that has been seen n times to the observed values

Parameters:

value - the observed value

n - the number of times to add value

subtract

public void subtract(double value)

Removes a value to the observed values (no checking is done that the value being removed was actually added).

Parameters:

value - the observed value

subtract

public void subtract(double value,
            double n)

Subtracts a value that has been seen n times from the observed values

Parameters:

value - the observed value

n - the number of times to subtract value

calculateDerived

public void calculateDerived()

Tells the object to calculate any statistics that don't have their values automatically updated during add. Currently updates the mean and standard deviation.

toString

public String toString()

Returns a string summarising the stats so far.

Overrides:

toString in class Object

Returns:

the summary string

getRevision

public String getRevision()

Returns the revision string.

Specified by:

getRevision in interface RevisionHandler

Returns:

the revision

main

public static void main(String[] args)

Tests the paired stats object from the command line. reads line from stdin, expecting two values per line.

Parameters:

args - ignored.