Package org.apache.datasketches.tuple

Class Union<S extends Summary>

java.lang.Object

org.apache.datasketches.tuple.Union<S>

Type Parameters:

S - Type of Summary

public class Union<S extends Summary>
extends Object

Compute the union of two or more generic tuple sketches or generic tuple sketches combined with theta sketches. A new instance represents an empty set.

Constructor Summary

Constructors

Constructor	Description
Union(int nomEntries, SummarySetOperations<S> summarySetOps)	Creates new Union instance.
Union(SummarySetOperations<S> summarySetOps)	Creates new Union instance with instructions on how to process two summaries that overlap.

Method Summary

Modifier and Type	Method	Description
CompactSketch<S>	getResult()	Gets the result of a sequence of stateful union operations as an unordered CompactSketch
CompactSketch<S>	getResult(boolean reset)	Gets the result of a sequence of stateful union operations as an unordered CompactSketch.
void	reset()	Resets the internal set to the initial state, which represents an empty set.
void	union(Sketch thetaSketch, S summary)	Performs a stateful union of the internal set with the given thetaSketch by combining entries using the hashes from the theta sketch and summary values from the given summary.
void	union(Sketch<S> tupleSketch)	Performs a stateful union of the internal set with the given tupleSketch.
CompactSketch<S>	union(Sketch<S> tupleSketch, Sketch thetaSketch, S summary)	Perform a stateless, pair-wise union operation between a tupleSketch and a thetaSketch.
CompactSketch<S>	union(Sketch<S> tupleSketchA, Sketch<S> tupleSketchB)	Perform a stateless, pair-wise union operation between two tuple sketches.

Methods inherited from class java.lang.Object

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

Constructor Detail

Union

public Union(SummarySetOperations<S> summarySetOps)

Creates new Union instance with instructions on how to process two summaries that overlap. This will have the default nominal entries (K).

Parameters:

summarySetOps - instance of SummarySetOperations

Union

public Union(int nomEntries,
             SummarySetOperations<S> summarySetOps)

Creates new Union instance.

Parameters:

nomEntries - nominal entries (K). Forced to the nearest power of 2 greater than given value.

summarySetOps - instance of SummarySetOperations

Method Detail

union

public CompactSketch<S> union(Sketch<S> tupleSketchA,
                              Sketch<S> tupleSketchB)

Perform a stateless, pair-wise union operation between two tuple sketches. The returned sketch will be cut back to the smaller of the two k values if required.

Nulls and empty sketches are ignored.

Parameters:

tupleSketchA - The first argument

tupleSketchB - The second argument

Returns:

the result ordered CompactSketch on the heap.

union

public CompactSketch<S> union(Sketch<S> tupleSketch,
                              Sketch thetaSketch,
                              S summary)

Perform a stateless, pair-wise union operation between a tupleSketch and a thetaSketch. The returned sketch will be cut back to the smaller of the two k values if required.

Nulls and empty sketches are ignored.

Parameters:

tupleSketch - The first argument

thetaSketch - The second argument

summary - the given proxy summary for the theta sketch, which doesn't have one. This may not be null.

Returns:

the result ordered CompactSketch on the heap.

union

public void union(Sketch<S> tupleSketch)

Performs a stateful union of the internal set with the given tupleSketch.

Parameters:

tupleSketch - input tuple sketch to merge with the internal set.

Nulls and empty sketches are ignored.

union

public void union(Sketch thetaSketch,
                  S summary)

Performs a stateful union of the internal set with the given thetaSketch by combining entries using the hashes from the theta sketch and summary values from the given summary.

Parameters:

thetaSketch - the given theta sketch input. If null or empty, it is ignored.

summary - the given proxy summary for the theta sketch, which doesn't have one. This may not be null.

getResult

public CompactSketch<S> getResult()

Gets the result of a sequence of stateful union operations as an unordered CompactSketch

Returns:

result of the stateful unions so far. The state of this operation is not reset after the result is returned.

getResult

public CompactSketch<S> getResult(boolean reset)

Gets the result of a sequence of stateful union operations as an unordered CompactSketch.

Parameters:

reset - If true, clears this operator to the empty state after this result is returned. Set this to false if you wish to obtain an intermediate result.

Returns:

result of the stateful union

reset

public void reset()

Resets the internal set to the initial state, which represents an empty set. This is only useful after sequences of stateful union operations.