Package org.roaringbitmap

Class FastAggregation

java.lang.Object

org.roaringbitmap.FastAggregation

public final class FastAggregation
extends java.lang.Object

Fast algorithms to aggregate many bitmaps.

Method Summary

Modifier and Type	Method	Description
static RoaringBitmap	and(long[] aggregationBuffer, RoaringBitmap... bitmaps)	Compute the AND aggregate.
static RoaringBitmap	and(java.util.Iterator<? extends RoaringBitmap> bitmaps)	Compute the AND aggregate.
static RoaringBitmap	and(RoaringBitmap... bitmaps)	Compute the AND aggregate.
static RoaringBitmap	horizontal_or(java.util.Iterator<? extends RoaringBitmap> bitmaps)	Deprecated.
static RoaringBitmap	horizontal_or(java.util.List<? extends RoaringBitmap> bitmaps)	Minimizes memory usage while computing the or aggregate on a moderate number of bitmaps.
static RoaringBitmap	horizontal_or(RoaringBitmap... bitmaps)	Minimizes memory usage while computing the or aggregate on a moderate number of bitmaps.
static RoaringBitmap	horizontal_xor(RoaringBitmap... bitmaps)	Minimizes memory usage while computing the xor aggregate on a moderate number of bitmaps.
static RoaringBitmap	naive_and(java.util.Iterator<? extends RoaringBitmap> bitmaps)	Compute overall AND between bitmaps two-by-two.
static RoaringBitmap	naive_and(RoaringBitmap... bitmaps)	Compute overall AND between bitmaps two-by-two.
static RoaringBitmap	naive_or(java.util.Iterator<? extends RoaringBitmap> bitmaps)	Compute overall OR between bitmaps two-by-two.
static RoaringBitmap	naive_or(RoaringBitmap... bitmaps)	Compute overall OR between bitmaps two-by-two.
static RoaringBitmap	naive_xor(java.util.Iterator<? extends RoaringBitmap> bitmaps)	Compute overall XOR between bitmaps two-by-two.
static RoaringBitmap	naive_xor(RoaringBitmap... bitmaps)	Compute overall XOR between bitmaps two-by-two.
static RoaringBitmap	or(java.util.Iterator<? extends RoaringBitmap> bitmaps)	Compute overall OR between bitmaps.
static RoaringBitmap	or(RoaringBitmap... bitmaps)	Compute overall OR between bitmaps.
static RoaringBitmap	priorityqueue_or(java.util.Iterator<? extends RoaringBitmap> bitmaps)	Uses a priority queue to compute the or aggregate.
static RoaringBitmap	priorityqueue_or(RoaringBitmap... bitmaps)	Uses a priority queue to compute the or aggregate.
static RoaringBitmap	priorityqueue_xor(RoaringBitmap... bitmaps)	Uses a priority queue to compute the xor aggregate.
static RoaringBitmap	workAndMemoryShyAnd(long[] buffer, RoaringBitmap... bitmaps)	Computes the intersection by first intersecting the keys, avoids materialising containers, limits memory usage.
static RoaringBitmap	workShyAnd(long[] buffer, RoaringBitmap... bitmaps)	Computes the intersection by first intersecting the keys, avoids materialising containers.
static RoaringBitmap	xor(java.util.Iterator<? extends RoaringBitmap> bitmaps)	Compute overall XOR between bitmaps.
static RoaringBitmap	xor(RoaringBitmap... bitmaps)	Compute overall XOR between bitmaps.

Methods inherited from class java.lang.Object

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

Method Detail

and

public static RoaringBitmap and(java.util.Iterator<? extends RoaringBitmap> bitmaps)

Compute the AND aggregate. In practice, calls {#link naive_and}

Parameters:

bitmaps - input bitmaps

Returns:

aggregated bitmap

and

public static RoaringBitmap and(RoaringBitmap... bitmaps)

Compute the AND aggregate.

Parameters:

bitmaps - input bitmaps

Returns:

aggregated bitmap

and

public static RoaringBitmap and(long[] aggregationBuffer,
                                RoaringBitmap... bitmaps)

Compute the AND aggregate.

Parameters:

aggregationBuffer - a buffer for aggregation

bitmaps - input bitmaps

Returns:

aggregated bitmap

horizontal_or

@Deprecated
public static RoaringBitmap horizontal_or(java.util.Iterator<? extends RoaringBitmap> bitmaps)

Deprecated.

Calls naive_or.

Parameters:

bitmaps - input bitmaps

Returns:

aggregated bitmap

horizontal_or

public static RoaringBitmap horizontal_or(java.util.List<? extends RoaringBitmap> bitmaps)

Minimizes memory usage while computing the or aggregate on a moderate number of bitmaps. This function runs in linearithmic (O(n log n)) time with respect to the number of bitmaps.

Parameters:

bitmaps - input bitmaps

Returns:

aggregated bitmap

See Also:

or(RoaringBitmap...)

horizontal_or

public static RoaringBitmap horizontal_or(RoaringBitmap... bitmaps)

Minimizes memory usage while computing the or aggregate on a moderate number of bitmaps. This function runs in linearithmic (O(n log n)) time with respect to the number of bitmaps.

Parameters:

bitmaps - input bitmaps

Returns:

aggregated bitmap

See Also:

or(RoaringBitmap...)

horizontal_xor

public static RoaringBitmap horizontal_xor(RoaringBitmap... bitmaps)

Minimizes memory usage while computing the xor aggregate on a moderate number of bitmaps. This function runs in linearithmic (O(n log n)) time with respect to the number of bitmaps.

Parameters:

bitmaps - input bitmaps

Returns:

aggregated bitmap

See Also:

xor(RoaringBitmap...)

naive_and

public static RoaringBitmap naive_and(java.util.Iterator<? extends RoaringBitmap> bitmaps)

Compute overall AND between bitmaps two-by-two. This function runs in linear time with respect to the number of bitmaps.

Parameters:

bitmaps - input bitmaps

Returns:

aggregated bitmap

naive_and

public static RoaringBitmap naive_and(RoaringBitmap... bitmaps)

Compute overall AND between bitmaps two-by-two. This function runs in linear time with respect to the number of bitmaps.

Parameters:

bitmaps - input bitmaps

Returns:

aggregated bitmap

workShyAnd

public static RoaringBitmap workShyAnd(long[] buffer,
                                       RoaringBitmap... bitmaps)

Computes the intersection by first intersecting the keys, avoids materialising containers.

Parameters:

buffer - an 8KB buffer

bitmaps - the inputs

Returns:

the intersection of the bitmaps

workAndMemoryShyAnd

public static RoaringBitmap workAndMemoryShyAnd(long[] buffer,
                                                RoaringBitmap... bitmaps)

Computes the intersection by first intersecting the keys, avoids materialising containers, limits memory usage. You must provide a long[] array of length at least 1024, initialized with zeroes. We do not check whether the array is initialized with zeros: it is the caller's responsability. You should expect this function to be slower than workShyAnd and the reduction in memory usage might be small.

Parameters:

buffer - should be a 1024-long array

bitmaps - the inputs

Returns:

the intersection of the bitmaps

naive_or

public static RoaringBitmap naive_or(java.util.Iterator<? extends RoaringBitmap> bitmaps)

Compute overall OR between bitmaps two-by-two. This function runs in linear time with respect to the number of bitmaps.

Parameters:

bitmaps - input bitmaps

Returns:

aggregated bitmap

naive_or

public static RoaringBitmap naive_or(RoaringBitmap... bitmaps)

Compute overall OR between bitmaps two-by-two. This function runs in linear time with respect to the number of bitmaps.

Parameters:

bitmaps - input bitmaps

Returns:

aggregated bitmap

naive_xor

public static RoaringBitmap naive_xor(java.util.Iterator<? extends RoaringBitmap> bitmaps)

Compute overall XOR between bitmaps two-by-two. This function runs in linear time with respect to the number of bitmaps.

Parameters:

bitmaps - input bitmaps

Returns:

aggregated bitmap

naive_xor

public static RoaringBitmap naive_xor(RoaringBitmap... bitmaps)

Compute overall XOR between bitmaps two-by-two. This function runs in linear time with respect to the number of bitmaps.

Parameters:

bitmaps - input bitmaps

Returns:

aggregated bitmap

or

public static RoaringBitmap or(java.util.Iterator<? extends RoaringBitmap> bitmaps)

Compute overall OR between bitmaps.

Parameters:

bitmaps - input bitmaps

Returns:

aggregated bitmap

or

public static RoaringBitmap or(RoaringBitmap... bitmaps)

Compute overall OR between bitmaps.

Parameters:

bitmaps - input bitmaps

Returns:

aggregated bitmap

priorityqueue_or

public static RoaringBitmap priorityqueue_or(java.util.Iterator<? extends RoaringBitmap> bitmaps)

Uses a priority queue to compute the or aggregate. This function runs in linearithmic (O(n log n)) time with respect to the number of bitmaps.

Parameters:

bitmaps - input bitmaps

Returns:

aggregated bitmap

See Also:

horizontal_or(RoaringBitmap...)

priorityqueue_or

public static RoaringBitmap priorityqueue_or(RoaringBitmap... bitmaps)

Uses a priority queue to compute the or aggregate. This function runs in linearithmic (O(n log n)) time with respect to the number of bitmaps.

Parameters:

bitmaps - input bitmaps

Returns:

aggregated bitmap

See Also:

horizontal_or(RoaringBitmap...)

priorityqueue_xor

public static RoaringBitmap priorityqueue_xor(RoaringBitmap... bitmaps)

Uses a priority queue to compute the xor aggregate. This function runs in linearithmic (O(n log n)) time with respect to the number of bitmaps.

Parameters:

bitmaps - input bitmaps

Returns:

aggregated bitmap

See Also:

horizontal_xor(RoaringBitmap...)

xor

public static RoaringBitmap xor(java.util.Iterator<? extends RoaringBitmap> bitmaps)

Compute overall XOR between bitmaps.

Parameters:

bitmaps - input bitmaps

Returns:

aggregated bitmap

xor

public static RoaringBitmap xor(RoaringBitmap... bitmaps)

Compute overall XOR between bitmaps.

Parameters:

bitmaps - input bitmaps

Returns:

aggregated bitmap