com.sun.faban.driver.util
Class PairwiseAggregator<T extends PairwiseAggregator.Aggregable<T>>

java.lang.Object
  com.sun.faban.driver.util.PairwiseAggregator<T>

public class PairwiseAggregator<T extends PairwiseAggregator.Aggregable<T>>
extends Object

The PairwiseAggregator implements the pairwise algorithm discussed by Chan's paper at Updating Formulae and a Pairwise Algorithm for Computing Sample Variances

Author:

akara

Nested Class Summary

static interface	PairwiseAggregator.Aggregable<T> Interface to an aggregable object.
static interface	PairwiseAggregator.Provider<T extends PairwiseAggregator.Aggregable<T>> Provider interface to provide objects to aggregate.

Constructor Summary

PairwiseAggregator(int nodeCount, PairwiseAggregator.Provider<T> provider)
Creates a PairwiseAggregator.

Method Summary

T	collectStats() Uses the pairwise algorithm to aggregate all the metrices together.

Methods inherited from class java.lang.Object

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

Constructor Detail

PairwiseAggregator

public PairwiseAggregator(int nodeCount,
                          PairwiseAggregator.Provider<T> provider)

Creates a PairwiseAggregator.

Parameters:

nodeCount - The number of objects to aggregate

provider - The object provider for aggregation

Method Detail

collectStats

public T collectStats()

Uses the pairwise algorithm to aggregate all the metrices together. This is to minimize floating point error and get mathematically stable results. It also minimizes memory use for a pairwise algorithm.

Returns:

The aggregated metric