de.jungblut.sketching

Class CountMinSketch<T>

java.lang.Object

de.jungblut.sketching.CountMinSketch<T>

public class CountMinSketch<T>
extends Object

Constructor Summary

Constructors

Constructor and Description
CountMinSketch(int tableWidth, int tableHeight, com.google.common.hash.Funnel<T> funnel) Creates a new CountMinSketch.

Method Summary

Modifier and Type	Method and Description
void	add(T obj) Adds this object to the min sketch.
int	approximateCount(T obj) Gives an approximate count of how often this element was seen through add(Object).

Methods inherited from class java.lang.Object

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

Constructor Detail

CountMinSketch

public CountMinSketch(int tableWidth,
                      int tableHeight,
                      com.google.common.hash.Funnel<T> funnel)

Creates a new CountMinSketch. This will allocate a 2D array of (tableHeight * tableWidth) integers, which is the whole memory constraint of the counting sketch. The height of the table tells how many hash functions to use.

Parameters:

tableWidth - the width of the counter table.

tableHeight - the height of the counter table (as in how many hashing functions to use).

funnel - the funnel to hash an object.

Method Detail

add

public void add(T obj)

Adds this object to the min sketch.

approximateCount

public int approximateCount(T obj)

Gives an approximate count of how often this element was seen through add(Object).

Returns:

0 if it was never seen, an approximate count otherwise.