Package org.apache.cassandra.utils

Class ExpMovingAverage

java.lang.Object

org.apache.cassandra.utils.ExpMovingAverage

All Implemented Interfaces:

MovingAverage

public class ExpMovingAverage
extends Object
implements MovingAverage

Sample-based exponential moving average. On every update a fraction of the current average is replaced by the new sample. New values have greater representation in the average, and older samples' effect exponentially decays with new data.

Method Summary

Modifier and Type	Method	Description
static ExpMovingAverage	decayBy10()	Create a ExpMovingAverage where older values have less than 1% effect after 10 samples.
static ExpMovingAverage	decayBy100()	Create a ExpMovingAverage where older values have less than 1% effect after 100 samples.
static MovingAverage	decayBy1000()	Create a ExpMovingAverage where older values have less than 1% effect after 1000 samples.
double	get()
String	toString()
MovingAverage	update(double val)
static ExpMovingAverage	withDecay(double ratio, int samples)	Create a ExpMovingAverage where older values have less effect than the given ratio after the given number of samples.

Methods inherited from class java.lang.Object

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

Method Details

decayBy1000

public static MovingAverage decayBy1000()

Create a ExpMovingAverage where older values have less than 1% effect after 1000 samples.

decayBy100

public static ExpMovingAverage decayBy100()

Create a ExpMovingAverage where older values have less than 1% effect after 100 samples.

decayBy10

public static ExpMovingAverage decayBy10()

Create a ExpMovingAverage where older values have less than 1% effect after 10 samples.

withDecay

public static ExpMovingAverage withDecay(double ratio,
 int samples)

Create a ExpMovingAverage where older values have less effect than the given ratio after the given number of samples.

update

public MovingAverage update(double val)

Specified by:

update in interface MovingAverage

get

public double get()

Specified by:

get in interface MovingAverage

toString

public String toString()

Overrides:

toString in class Object