com.clearspring.analytics.stream.cardinality

Class LinearCounting.Builder

java.lang.Object

com.clearspring.analytics.stream.cardinality.LinearCounting.Builder

All Implemented Interfaces:

IBuilder<ICardinality>, Serializable

Enclosing class:

LinearCounting

public static class LinearCounting.Builder
extends Object
implements IBuilder<ICardinality>, Serializable

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field and Description
protected static int[]	onePercentErrorLength Taken from Table II of Whang et al.
protected int	size

Constructor Summary

Constructors

Constructor and Description
Builder()
Builder(int size)

Method Summary

Modifier and Type	Method and Description
LinearCounting	build()
protected static int	lerp(int x0, int y0, int x1, int y1, int x)
static LinearCounting.Builder	onePercentError(int maxCardinality) Returns a LinearCounting.Builder that generates an LC estimator which keeps estimates below 1% error on average and has a low likelihood of saturation (0.7%) for any stream with cardinality less than maxCardinality
int	sizeof()
static LinearCounting.Builder	withError(double eps, int maxCardinality) Builds Linear Counter with arbitrary standard error and maximum expected cardinality.

Methods inherited from class java.lang.Object

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

Field Detail

onePercentErrorLength

protected static final int[] onePercentErrorLength

Taken from Table II of Whang et al.

size

protected final int size

Constructor Detail

Builder

public Builder()

Builder

public Builder(int size)

Method Detail

build

public LinearCounting build()

Specified by:

build in interface IBuilder<ICardinality>

sizeof

public int sizeof()

Specified by:

sizeof in interface IBuilder<ICardinality>

onePercentError

public static LinearCounting.Builder onePercentError(int maxCardinality)

Returns a LinearCounting.Builder that generates an LC estimator which keeps estimates below 1% error on average and has a low likelihood of saturation (0.7%) for any stream with cardinality less than maxCardinality

Parameters:

maxCardinality -

Returns:

Throws:

IllegalArgumentException - if maxCardinality is not a positive integer

withError

public static LinearCounting.Builder withError(double eps,
                                               int maxCardinality)

Builds Linear Counter with arbitrary standard error and maximum expected cardinality.

This method is more compute intensive than onePercentError(int) as it is perform solving precision inequality in runtime. Therefore, onePercentError(int) should be used whenever possible.

Parameters:

eps - standard error as a fraction (e.g. 0.01 for 1%)

maxCardinality - maximum expected cardinality

lerp

protected static int lerp(int x0,
                          int y0,
                          int x1,
                          int y1,
                          int x)

Parameters:

x0 -

y0 -

x1 -

y1 -

x -

Returns:

linear interpolation