org.apache.commons.math.stat.univariate.moment
Class SecondMoment

java.lang.Object
  extended byorg.apache.commons.math.stat.univariate.AbstractUnivariateStatistic
      extended byorg.apache.commons.math.stat.univariate.AbstractStorelessUnivariateStatistic
          extended byorg.apache.commons.math.stat.univariate.moment.FirstMoment
              extended byorg.apache.commons.math.stat.univariate.moment.SecondMoment
All Implemented Interfaces:
Serializable, StorelessUnivariateStatistic, UnivariateStatistic
Direct Known Subclasses:
ThirdMoment

public class SecondMoment
extends FirstMoment
implements Serializable

The SecondMoment is calculated using the following recursive strategy . Both incremental and evaluation strategies currently use this approach.

Version:
$Revision: 1.12 $ $Date: 2003/11/19 03:28:24 $
See Also:
Serialized Form

Field Summary
protected  double m2
          second moment of values that have been added
protected  double n1
          temporary internal state made availabel for higher order moments
 
Fields inherited from class org.apache.commons.math.stat.univariate.moment.FirstMoment
dev, m1, n, n0, v
 
Constructor Summary
SecondMoment()
           
 
Method Summary
 void clear()
          Clears all the internal state of the Statistic
 double getResult()
          Returns the current state of the statistic after the last increment.
 void increment(double d)
          Increments the internal state of the Storagless Implementation.
 
Methods inherited from class org.apache.commons.math.stat.univariate.moment.FirstMoment
getN
 
Methods inherited from class org.apache.commons.math.stat.univariate.AbstractStorelessUnivariateStatistic
evaluate
 
Methods inherited from class org.apache.commons.math.stat.univariate.AbstractUnivariateStatistic
evaluate, test
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 
Methods inherited from interface org.apache.commons.math.stat.univariate.UnivariateStatistic
evaluate
 

Field Detail

m2

protected double m2
second moment of values that have been added


n1

protected double n1
temporary internal state made availabel for higher order moments

Constructor Detail

SecondMoment

public SecondMoment()
Method Detail

increment

public void increment(double d)
Description copied from interface: StorelessUnivariateStatistic
Increments the internal state of the Storagless Implementation.

Specified by:
increment in interface StorelessUnivariateStatistic
Overrides:
increment in class FirstMoment
See Also:
StorelessUnivariateStatistic.increment(double)

clear

public void clear()
Description copied from interface: StorelessUnivariateStatistic
Clears all the internal state of the Statistic

Specified by:
clear in interface StorelessUnivariateStatistic
Overrides:
clear in class FirstMoment
See Also:
StorelessUnivariateStatistic.clear()

getResult

public double getResult()
Description copied from interface: StorelessUnivariateStatistic
Returns the current state of the statistic after the last increment.

Specified by:
getResult in interface StorelessUnivariateStatistic
Overrides:
getResult in class FirstMoment
See Also:
StorelessUnivariateStatistic.getResult()


Copyright © 2003-2004 Apache Software Foundation. All Rights Reserved.