com.googlecode.javaewah

Class FastAggregation

java.lang.Object

com.googlecode.javaewah.FastAggregation

public final class FastAggregation
extends Object

Fast algorithms to aggregate many bitmaps. These algorithms are just given as reference. They may not be faster than the corresponding methods in the EWAHCompressedBitmap class.

Author:

Daniel Lemire

Method Summary

Modifier and Type	Method and Description
static EWAHCompressedBitmap	bufferedand(int bufSize, EWAHCompressedBitmap... bitmaps) Compute the and aggregate using a temporary uncompressed bitmap.
static void	bufferedandWithContainer(BitmapStorage container, int bufSize, EWAHCompressedBitmap... bitmaps) Compute the and aggregate using a temporary uncompressed bitmap.
static EWAHCompressedBitmap	bufferedor(int bufSize, EWAHCompressedBitmap... bitmaps) Compute the or aggregate using a temporary uncompressed bitmap.
static void	bufferedorWithContainer(BitmapStorage container, int bufSize, EWAHCompressedBitmap... bitmaps) Compute the or aggregate using a temporary uncompressed bitmap.
static EWAHCompressedBitmap	bufferedxor(int bufSize, EWAHCompressedBitmap... bitmaps) Compute the xor aggregate using a temporary uncompressed bitmap.
static void	bufferedxorWithContainer(BitmapStorage container, int bufSize, EWAHCompressedBitmap... bitmaps) Compute the xor aggregate using a temporary uncompressed bitmap.
static void	legacy_orWithContainer(BitmapStorage container, EWAHCompressedBitmap... bitmaps) Deprecated. use EWAHCompressedBitmap.or instead
static EWAHCompressedBitmap	or(EWAHCompressedBitmap... bitmaps) Simple algorithm that computes the OR aggregate.
static EWAHCompressedBitmap	or(Iterator<EWAHCompressedBitmap> bitmaps) Simple algorithm that computes the OR aggregate.
static <T extends LogicalElement> T	or(T... bitmaps) Uses a priority queue to compute the or aggregate.
static void	orToContainer(BitmapStorage container, EWAHCompressedBitmap... bitmaps) Uses a priority queue to compute the or aggregate.
static EWAHCompressedBitmap	xor(EWAHCompressedBitmap... bitmaps) Simple algorithm that computes the XOR aggregate.
static EWAHCompressedBitmap	xor(Iterator<EWAHCompressedBitmap> bitmaps) Simple algorithm that computes the XOR aggregate.
static <T extends LogicalElement> T	xor(T... bitmaps) Uses a priority queue to compute the xor aggregate.
static void	xorToContainer(BitmapStorage container, EWAHCompressedBitmap... bitmaps) Uses a priority queue to compute the xor aggregate.

Methods inherited from class java.lang.Object

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

Method Detail

bufferedand

public static EWAHCompressedBitmap bufferedand(int bufSize,
                                               EWAHCompressedBitmap... bitmaps)

Compute the and aggregate using a temporary uncompressed bitmap.

Parameters:

bitmaps - the source bitmaps

bufSize - buffer size used during the computation in 64-bit words (per input bitmap)

Returns:

the or aggregate.

bufferedandWithContainer

public static void bufferedandWithContainer(BitmapStorage container,
                                            int bufSize,
                                            EWAHCompressedBitmap... bitmaps)

Compute the and aggregate using a temporary uncompressed bitmap.

Parameters:

container - where the aggregate is written

bufSize - buffer size used during the computation in 64-bit words (per input bitmap)

bitmaps - the source bitmaps

bufferedor

public static EWAHCompressedBitmap bufferedor(int bufSize,
                                              EWAHCompressedBitmap... bitmaps)

Compute the or aggregate using a temporary uncompressed bitmap.

Parameters:

bitmaps - the source bitmaps

bufSize - buffer size used during the computation in 64-bit words

Returns:

the or aggregate.

bufferedorWithContainer

public static void bufferedorWithContainer(BitmapStorage container,
                                           int bufSize,
                                           EWAHCompressedBitmap... bitmaps)

Compute the or aggregate using a temporary uncompressed bitmap.

Parameters:

container - where the aggregate is written

bufSize - buffer size used during the computation in 64-bit words

bitmaps - the source bitmaps

bufferedxor

public static EWAHCompressedBitmap bufferedxor(int bufSize,
                                               EWAHCompressedBitmap... bitmaps)

Compute the xor aggregate using a temporary uncompressed bitmap.

Parameters:

bitmaps - the source bitmaps

bufSize - buffer size used during the computation in 64-bit words

Returns:

the xor aggregate.

bufferedxorWithContainer

public static void bufferedxorWithContainer(BitmapStorage container,
                                            int bufSize,
                                            EWAHCompressedBitmap... bitmaps)

Compute the xor aggregate using a temporary uncompressed bitmap.

Parameters:

container - where the aggregate is written

bufSize - buffer size used during the computation in 64-bit words

bitmaps - the source bitmaps

or

public static <T extends LogicalElement> T or(T... bitmaps)

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

Type Parameters:

T - a class extending LogicalElement (like a compressed bitmap)

Parameters:

bitmaps - bitmaps to be aggregated

Returns:

the or aggregate

orToContainer

public static void orToContainer(BitmapStorage container,
                                 EWAHCompressedBitmap... bitmaps)

Uses a priority queue to compute the or aggregate. The content of the container is overwritten. This algorithm runs in linearithmic time (O(n log n)) with respect to the number of bitmaps.

Parameters:

container - where we write the result

bitmaps - to be aggregated

or

public static EWAHCompressedBitmap or(EWAHCompressedBitmap... bitmaps)

Simple algorithm that computes the OR aggregate.

Parameters:

bitmaps - input bitmaps

Returns:

new bitmap containing the aggregate

xor

public static EWAHCompressedBitmap xor(EWAHCompressedBitmap... bitmaps)

Simple algorithm that computes the XOR aggregate.

Parameters:

bitmaps - input bitmaps

Returns:

new bitmap containing the aggregate

or

public static EWAHCompressedBitmap or(Iterator<EWAHCompressedBitmap> bitmaps)

Simple algorithm that computes the OR aggregate.

Parameters:

bitmaps - input bitmaps

Returns:

new bitmap containing the aggregate

xor

public static EWAHCompressedBitmap xor(Iterator<EWAHCompressedBitmap> bitmaps)

Simple algorithm that computes the XOR aggregate.

Parameters:

bitmaps - input bitmaps

Returns:

new bitmap containing the aggregate

xor

public static <T extends LogicalElement> T xor(T... bitmaps)

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

Type Parameters:

T - a class extending LogicalElement (like a compressed bitmap)

Parameters:

bitmaps - bitmaps to be aggregated

Returns:

the xor aggregate

xorToContainer

public static void xorToContainer(BitmapStorage container,
                                  EWAHCompressedBitmap... bitmaps)

Uses a priority queue to compute the xor aggregate. The content of the container is overwritten. This algorithm runs in linearithmic time (O(n log n)) with respect to the number of bitmaps.

Parameters:

container - where we write the result

bitmaps - to be aggregated

legacy_orWithContainer

@Deprecated
public static void legacy_orWithContainer(BitmapStorage container,
                                                      EWAHCompressedBitmap... bitmaps)

Deprecated. use EWAHCompressedBitmap.or instead

For internal use. Computes the bitwise or of the provided bitmaps and stores the result in the container. (This used to be the default.)

Parameters:

container - where store the result

bitmaps - to be aggregated

Since:

0.4.0