Package org.apache.beam.sdk.extensions.sketching

Class SketchFrequencies.PerKeySketch<K,V>

java.lang.Object

org.apache.beam.sdk.transforms.PTransform<PCollection<KV<K,V>>,PCollection<KV<K,SketchFrequencies.Sketch<V>>>>

org.apache.beam.sdk.extensions.sketching.SketchFrequencies.PerKeySketch<K,V>

Type Parameters:

K - type of the keys mapping the elements

V - type of the values being combined per key

All Implemented Interfaces:

Serializable, HasDisplayData

Enclosing class:

SketchFrequencies

public abstract static class SketchFrequencies.PerKeySketch<K,V>
extends PTransform<PCollection<KV<K,V>>,PCollection<KV<K,SketchFrequencies.Sketch<V>>>>

Implementation of SketchFrequencies.perKey().

See Also:

• Serialized Form

Field Summary

Fields inherited from class org.apache.beam.sdk.transforms.PTransform

annotations, displayData, name, resourceHints

Constructor Summary

Constructors

Constructor	Description
PerKeySketch()

Method Summary

Modifier and Type	Method	Description
PCollection<KV<K,SketchFrequencies.Sketch<V>>>	expand(PCollection<KV<K,V>> input)	Override this method to specify how this PTransform should be expanded on the given InputT.
SketchFrequencies.PerKeySketch<K,V>	withConfidence(double conf)	Sets the confidence value, i.e.
SketchFrequencies.PerKeySketch<K,V>	withRelativeError(double eps)	Sets the relative error epsilon.

Methods inherited from class org.apache.beam.sdk.transforms.PTransform

addAnnotation, compose, compose, getAdditionalInputs, getAnnotations, getDefaultOutputCoder, getDefaultOutputCoder, getDefaultOutputCoder, getKindString, getName, getResourceHints, populateDisplayData, setDisplayData, setResourceHints, toString, validate, validate

Methods inherited from class java.lang.Object

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

Constructor Details

PerKeySketch

public PerKeySketch()

Method Details

withRelativeError

public SketchFrequencies.PerKeySketch<K,V> withRelativeError(double eps)

Sets the relative error epsilon.

Keep in mind that the lower the epsilon value, the greater the width.

Parameters:

eps - the error relative to the total number of distinct elements

withConfidence

public SketchFrequencies.PerKeySketch<K,V> withConfidence(double conf)

Sets the confidence value, i.e. the probability that the relative error is lower or equal to epsilon.

Keep in mind that the greater the confidence, the greater the depth.

Parameters:

conf - the confidence in the result to not exceed the relative error

expand

public PCollection<KV<K,SketchFrequencies.Sketch<V>>> expand(PCollection<KV<K,V>> input)

Description copied from class: PTransform

Override this method to specify how this PTransform should be expanded on the given InputT.

NOTE: This method should not be called directly. Instead apply the PTransform should be applied to the InputT using the apply method.

Composite transforms, which are defined in terms of other transforms, should return the output of one of the composed transforms. Non-composite transforms, which do not apply any transforms internally, should return a new unbound output and register evaluators (via backend-specific registration methods).

Specified by:

expand in class PTransform<PCollection<KV<K,V>>,PCollection<KV<K,SketchFrequencies.Sketch<V>>>>