org.apache.mahout.cf.taste.impl.common

Class FullRunningAverage

java.lang.Object

org.apache.mahout.cf.taste.impl.common.FullRunningAverage

All Implemented Interfaces:

Serializable, RunningAverage

Direct Known Subclasses:

FullRunningAverageAndStdDev

public class FullRunningAverage
extends Object
implements RunningAverage, Serializable

A simple class that can keep track of a running average of a series of numbers. One can add to or remove from the series, as well as update a datum in the series. The class does not actually keep track of the series of values, just its running average, so it doesn't even matter if you remove/change a value that wasn't added.

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor and Description
FullRunningAverage()
FullRunningAverage(int count, double average)

Method Summary

Modifier and Type	Method and Description
void	addDatum(double datum)
void	changeDatum(double delta)
double	getAverage()
int	getCount()
RunningAverage	inverse()
void	removeDatum(double datum)
String	toString()

Methods inherited from class java.lang.Object

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

Constructor Detail

FullRunningAverage

public FullRunningAverage()

FullRunningAverage

public FullRunningAverage(int count,
                          double average)

Method Detail

addDatum

public void addDatum(double datum)

Specified by:

addDatum in interface RunningAverage

Parameters:

datum - new item to add to the running average

removeDatum

public void removeDatum(double datum)

Specified by:

removeDatum in interface RunningAverage

Parameters:

datum - item to remove to the running average

Throws:

IllegalStateException - if count is 0

changeDatum

public void changeDatum(double delta)

Specified by:

changeDatum in interface RunningAverage

Parameters:

delta - amount by which to change a datum in the running average

Throws:

IllegalStateException - if count is 0

getCount

public int getCount()

Specified by:

getCount in interface RunningAverage

getAverage

public double getAverage()

Specified by:

getAverage in interface RunningAverage

inverse

public RunningAverage inverse()

Specified by:

inverse in interface RunningAverage

Returns:

a (possibly immutable) object whose average is the negative of this object's

toString

public String toString()

Overrides:

toString in class Object