com.espertech.esper.epl.approx

Class CountMinSketchStateHashes

java.lang.Object

com.espertech.esper.epl.approx.CountMinSketchStateHashes

public class CountMinSketchStateHashes
extends Object

Count-min sketch (or CM sketch) is a probabilistic sub-linear space streaming algorithm (source: Wikipedia, see http://en.wikipedia.org/wiki/Count%E2%80%93min_sketch)

Count-min sketch computes an approximate frequency and thereby top-k or heavy-hitters.

Paper: Graham Cormode and S. Muthukrishnan. An improved data stream summary: The Count-Min sketch and its applications. 2004. 10.1016/j.jalgor.2003.12.001 http://dl.acm.org/citation.cfm?id=1073718

Constructor Summary

Constructors

Constructor and Description
CountMinSketchStateHashes(int depth, int width, long[][] table, long[] hash, long total)

Method Summary

Modifier and Type	Method and Description
void	add(byte[] item, long count)
long	estimateCount(byte[] item)
int	getDepth()
long[]	getHash()
long[][]	getTable()
long	getTotal()
int	getWidth()
void	incTotal(long count)
static CountMinSketchStateHashes	makeState(CountMinSketchSpecHashes spec)

Methods inherited from class java.lang.Object

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

Constructor Detail

CountMinSketchStateHashes

public CountMinSketchStateHashes(int depth,
                                 int width,
                                 long[][] table,
                                 long[] hash,
                                 long total)

Method Detail

makeState

public static CountMinSketchStateHashes makeState(CountMinSketchSpecHashes spec)

getTable

public long[][] getTable()

getHash

public long[] getHash()

getDepth

public int getDepth()

getWidth

public int getWidth()

incTotal

public void incTotal(long count)

getTotal

public long getTotal()

estimateCount

public long estimateCount(byte[] item)

add

public void add(byte[] item,
                long count)