Package com.googlecode.javaewah32.symmetric

Class ThresholdFuncBitmap32

java.lang.Object

com.googlecode.javaewah32.symmetric.UpdateableBitmapFunction32

com.googlecode.javaewah32.symmetric.ThresholdFuncBitmap32

public final class ThresholdFuncBitmap32
extends UpdateableBitmapFunction32

A threshold Boolean function returns true if the number of true values exceed a threshold. It is a symmetric Boolean function. This class implements an algorithm described in the following paper: Owen Kaser and Daniel Lemire, Compressed bitmap indexes: beyond unions and intersections http://arxiv.org/abs/1402.4466 It is not thread safe: you should use one object per thread.

Since:

0.8.2

See Also:

• http://en.wikipedia.org/wiki/Symmetric_Boolean_function

Field Summary

Fields

Modifier and Type	Field	Description
private final int[]	bufcounters
private int[]	buffers
private int	bufferUsed
private final int	min
private static final int[]	zeroes64

Fields inherited from class com.googlecode.javaewah32.symmetric.UpdateableBitmapFunction32

b, hammingWeight, litWeight, litwlist, rw

Constructor Summary

Constructors

Constructor	Description
ThresholdFuncBitmap32(int min)	Construction a threshold function with a given threshold

Method Summary

Modifier and Type	Method	Description
private void	andLiterals(BitmapStorage32 out, int runBegin, int runLength)
void	dispatch(BitmapStorage32 out, int runBegin, int runend)	Writes out the answer.
private void	generalLiterals(int deficit, BitmapStorage32 out, int runBegin, int runLength)
private void	orLiterals(BitmapStorage32 out, int runBegin, int runLength)
private int	threshold2buf(int t, int[] buf, int bufUsed)
private static int	threshold3(int t, int[] buffers, int bufUsed)
private int	threshold4(int t, int[] buf, int bufUsed)

Methods inherited from class com.googlecode.javaewah32.symmetric.UpdateableBitmapFunction32

clearLiteral, fillWithLiterals, getLiterals, getNumberOfLiterals, resize, setLiteral, setOne, setZero

Methods inherited from class java.lang.Object

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

Field Details

min

private final int min

buffers

private int[] buffers

bufferUsed

private int bufferUsed

bufcounters

private final int[] bufcounters

zeroes64

private static final int[] zeroes64

Constructor Details

ThresholdFuncBitmap32

public ThresholdFuncBitmap32(int min)

Construction a threshold function with a given threshold

Parameters:

min - threshold

Method Details

dispatch

public void dispatch(BitmapStorage32 out,
 int runBegin,
 int runend)

Description copied from class: UpdateableBitmapFunction32

Writes out the answer.

Specified by:

dispatch in class UpdateableBitmapFunction32

Parameters:

out - output buffer

runBegin - beginning of the run

runend - end of the run

threshold2buf

private int threshold2buf(int t,
 int[] buf,
 int bufUsed)

threshold3

private static int threshold3(int t,
 int[] buffers,
 int bufUsed)

threshold4

private int threshold4(int t,
 int[] buf,
 int bufUsed)

orLiterals

private void orLiterals(BitmapStorage32 out,
 int runBegin,
 int runLength)

andLiterals

private void andLiterals(BitmapStorage32 out,
 int runBegin,
 int runLength)

generalLiterals

private void generalLiterals(int deficit,
 BitmapStorage32 out,
 int runBegin,
 int runLength)