Package org.apache.datasketches.quantiles

Class DoublesSketchBuilder

java.lang.Object

org.apache.datasketches.quantiles.DoublesSketchBuilder

public class DoublesSketchBuilder
extends Object

For building a new quantiles DoublesSketch.

Author:

Lee Rhodes

Constructor Summary

Constructors

Constructor	Description
DoublesSketchBuilder()	Constructor for a new DoublesSketchBuilder.

Method Summary

Modifier and Type	Method	Description
UpdateDoublesSketch	build()	Returns an UpdateDoublesSketch with the current configuration of this Builder.
UpdateDoublesSketch	build(org.apache.datasketches.memory.WritableMemory dstMem)	Returns a quantiles UpdateDoublesSketch with the current configuration of this builder and the specified backing destination Memory store.
int	getK()	Gets the current configured k
DoublesSketchBuilder	setK(int k)	Sets the parameter k that determines the accuracy and size of the sketch.
String	toString()	Creates a human readable string that describes the current configuration of this builder.

Methods inherited from class java.lang.Object

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

Constructor Detail

DoublesSketchBuilder

public DoublesSketchBuilder()

Constructor for a new DoublesSketchBuilder. The default configuration is

• k: 128. This produces a normalized rank error of about 1.7%
• Memory: null

Method Detail

setK

public DoublesSketchBuilder setK(int k)

Sets the parameter k that determines the accuracy and size of the sketch.

Parameters:

k - determines the accuracy and size of the sketch. It is recommended that k be a power of 2 to enable unioning of sketches with different k. It is only possible to union from larger k to smaller k.

Returns:

this builder

getK

public int getK()

Gets the current configured k

Returns:

the current configured k

build

public UpdateDoublesSketch build()

Returns an UpdateDoublesSketch with the current configuration of this Builder.

Returns:

a UpdateDoublesSketch

build

public UpdateDoublesSketch build(org.apache.datasketches.memory.WritableMemory dstMem)

Returns a quantiles UpdateDoublesSketch with the current configuration of this builder and the specified backing destination Memory store.

Parameters:

dstMem - destination memory for use by the sketch

Returns:

an UpdateDoublesSketch

toString

public String toString()

Creates a human readable string that describes the current configuration of this builder.

Overrides:

toString in class Object