Package org.apache.pekko.remote.artery.compress

Class CountMinSketch

java.lang.Object

org.apache.pekko.remote.artery.compress.CountMinSketch

public class CountMinSketch
extends Object

INTERNAL API: Count-Min Sketch datastructure.

Not thread-safe.

An Improved Data Stream Summary: The Count-Min Sketch and its Applications https://web.archive.org/web/20060907232042/http://www.eecs.harvard.edu/~michaelm/CS222/countmin.pdf This implementation is mostly taken and adjusted from the Apache V2 licensed project `stream-lib`, located here: https://github.com/clearspring/stream-lib/blob/master/src/main/java/com/clearspring/analytics/stream/frequency/CountMinSketch.java

Constructor Summary

Constructors

Constructor	Description
CountMinSketch(int depth, int width, int seed)

Method Summary

Modifier and Type	Method	Description
long	addObjectAndEstimateCount(Object item, long count)	Similar to add, however we reuse the fact that the hask buckets have to be calculated for add already, and a separate estimateCount operation would have to calculate them again, so we do it all in one go.
double	confidence()
long	estimateCount(Object item)	The estimate is correct within 'epsilon' * (total item count), with probability confidence.
double	relativeError()	Referred to as epsilon in the whitepaper
long	size()
String	toString()

Methods inherited from class java.lang.Object

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

Constructor Details

CountMinSketch

public CountMinSketch(int depth,
 int width,
 int seed)

Method Details

relativeError

public double relativeError()

Referred to as epsilon in the whitepaper

confidence

public double confidence()

addObjectAndEstimateCount

public long addObjectAndEstimateCount(Object item,
 long count)

Similar to add, however we reuse the fact that the hask buckets have to be calculated for add already, and a separate estimateCount operation would have to calculate them again, so we do it all in one go.

size

public long size()

estimateCount

public long estimateCount(Object item)

The estimate is correct within 'epsilon' * (total item count), with probability confidence.

toString

public String toString()

Overrides:

toString in class Object