com.googlecode.javaewah.symmetric
Class ThresholdFuncBitmap

java.lang.Object
  com.googlecode.javaewah.symmetric.UpdateableBitmapFunction
      com.googlecode.javaewah.symmetric.ThresholdFuncBitmap

public final class ThresholdFuncBitmap
extends UpdateableBitmapFunction

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:

0.8.0

Author:

Daniel Lemire

See Also:

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

Constructor Summary

ThresholdFuncBitmap(int min)
Construction a threshold function with a given threshold

Method Summary

void	dispatch(BitmapStorage out, int runbegin, int runend) Writes out the answer.

Methods inherited from class com.googlecode.javaewah.symmetric.UpdateableBitmapFunction

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

Constructor Detail

ThresholdFuncBitmap

public ThresholdFuncBitmap(int min)

Construction a threshold function with a given threshold

Parameters:

min - threshold

Method Detail

dispatch

public void dispatch(BitmapStorage out,
                     int runbegin,
                     int runend)

Description copied from class: UpdateableBitmapFunction

Writes out the answer.

Specified by:

dispatch in class UpdateableBitmapFunction

Parameters:

out - output buffer

runbegin - beginning of the run

runend - end of the run