org.apache.spark.util

Class StatCounter

Object

org.apache.spark.util.StatCounter

All Implemented Interfaces:

java.io.Serializable

public class StatCounter
extends Object
implements scala.Serializable

A class for tracking the statistics of a set of numbers (count, mean and variance) in a numerically robust way. Includes support for merging two StatCounters. Based on Welford and Chan's algorithms for running variance.

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor and Description
StatCounter() Initialize the StatCounter with no values.
StatCounter(scala.collection.TraversableOnce<Object> values)

Method Summary

Methods

Modifier and Type	Method and Description
static StatCounter	apply(scala.collection.Seq<Object> values) Build a StatCounter from a list of values passed as variable-length arguments.
static StatCounter	apply(scala.collection.TraversableOnce<Object> values) Build a StatCounter from a list of values.
StatCounter	copy() Clone this StatCounter
long	count()
double	max()
double	mean()
StatCounter	merge(double value) Add a value into this StatCounter, updating the internal statistics.
StatCounter	merge(StatCounter other) Merge another StatCounter into this one, adding up the internal statistics.
StatCounter	merge(scala.collection.TraversableOnce<Object> values) Add multiple values into this StatCounter, updating the internal statistics.
double	min()
double	sampleStdev() Return the sample standard deviation of the values, which corrects for bias in estimating the variance by dividing by N-1 instead of N.
double	sampleVariance() Return the sample variance, which corrects for bias in estimating the variance by dividing by N-1 instead of N.
double	stdev() Return the standard deviation of the values.
double	sum()
String	toString()
double	variance() Return the variance of the values.

Methods inherited from class Object

equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

StatCounter

public StatCounter(scala.collection.TraversableOnce<Object> values)

StatCounter

public StatCounter()

Initialize the StatCounter with no values.

Method Detail

apply

public static StatCounter apply(scala.collection.TraversableOnce<Object> values)

Build a StatCounter from a list of values.

apply

public static StatCounter apply(scala.collection.Seq<Object> values)

Build a StatCounter from a list of values passed as variable-length arguments.

merge

public StatCounter merge(double value)

Add a value into this StatCounter, updating the internal statistics.

merge

public StatCounter merge(scala.collection.TraversableOnce<Object> values)

Add multiple values into this StatCounter, updating the internal statistics.

merge

public StatCounter merge(StatCounter other)

Merge another StatCounter into this one, adding up the internal statistics.

copy

public StatCounter copy()

Clone this StatCounter

count

public long count()

mean

public double mean()

sum

public double sum()

max

public double max()

min

public double min()

variance

public double variance()

Return the variance of the values.

sampleVariance

public double sampleVariance()

Return the sample variance, which corrects for bias in estimating the variance by dividing by N-1 instead of N.

Returns:

(undocumented)

stdev

public double stdev()

Return the standard deviation of the values.

sampleStdev

public double sampleStdev()

Return the sample standard deviation of the values, which corrects for bias in estimating the variance by dividing by N-1 instead of N.

Returns:

(undocumented)

toString

public String toString()

Overrides:

toString in class Object