Wikimedia\PSquare Class Reference

Represents a running, online estimate of a p-quantile for a series of observations using the P-squared algorithm. More...

Public Member Functions
	__construct ( $p=0.5)
	__serialize ()
	Export state, e.g.
	__unserialize (array $data)
	getCount ()
	Get the total number of accumulated observations.
	addObservation ( $x)
	Add an observation.
	getValue ()
	Get the estimated p-quantile value.

Detailed Description

Represents a running, online estimate of a p-quantile for a series of observations using the P-squared algorithm.

The algorithm is from "The P-Square Algorithm for Dynamic Calculation of Percentiles and Histograms without Storing Observations," Communications of the ACM, October 1985 by R. Jain and I. Chlamtac.

Constructor & Destructor Documentation

__construct()

Wikimedia\PSquare::__construct

(

$p = 0.5

)

Parameters

float

$p

the percentile (defaults to 0.5, or median).

Member Function Documentation

__serialize()

Wikimedia\PSquare::__serialize

(

)

Export state, e.g.

for serializing and caching.

Returns

array

__unserialize()

Wikimedia\PSquare::__unserialize

(

array

$data

)

Parameters

array

$data

addObservation()

Wikimedia\PSquare::addObservation

(

$x

)

Add an observation.

Parameters

int | float

$x

Value to add

getCount()

Wikimedia\PSquare::getCount

(

)

Get the total number of accumulated observations.

Returns

int

getValue()

Wikimedia\PSquare::getValue

(

)

Get the estimated p-quantile value.

Returns

float

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The documentation for this class was generated from the following file:

• src/PSquare.php