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

Class WeightedRunningAverageAndStdDev

java.lang.Object

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

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

All Implemented Interfaces:

Serializable, RunningAverage, RunningAverageAndStdDev

public final class WeightedRunningAverageAndStdDev
extends WeightedRunningAverage
implements RunningAverageAndStdDev

This subclass also provides for a weighted estimate of the sample standard deviation. See estimate formulae here.

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor and Description
WeightedRunningAverageAndStdDev()

Method Summary

Modifier and Type	Method and Description
void	addDatum(double datum, double weight)
void	changeDatum(double delta, double weight)
double	getStandardDeviation()
RunningAverageAndStdDev	inverse()
void	removeDatum(double datum, double weight)
String	toString()

Methods inherited from class org.apache.mahout.cf.taste.impl.common.WeightedRunningAverage

addDatum, changeDatum, getAverage, getCount, getTotalWeight, removeDatum

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.apache.mahout.cf.taste.impl.common.RunningAverage

addDatum, changeDatum, getAverage, getCount, removeDatum

Constructor Detail

WeightedRunningAverageAndStdDev

public WeightedRunningAverageAndStdDev()

Method Detail

addDatum

public void addDatum(double datum,
                     double weight)

Overrides:

addDatum in class WeightedRunningAverage

removeDatum

public void removeDatum(double datum,
                        double weight)

Overrides:

removeDatum in class WeightedRunningAverage

changeDatum

public void changeDatum(double delta,
                        double weight)

Overrides:

changeDatum in class WeightedRunningAverage

Throws:

UnsupportedOperationException

getStandardDeviation

public double getStandardDeviation()

Specified by:

getStandardDeviation in interface RunningAverageAndStdDev

Returns:

standard deviation of data

inverse

public RunningAverageAndStdDev inverse()

Specified by:

inverse in interface RunningAverage

Specified by:

inverse in interface RunningAverageAndStdDev

Overrides:

inverse in class WeightedRunningAverage

Returns:

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

toString

public String toString()

Overrides:

toString in class WeightedRunningAverage