Package org.elasticsearch.search.aggregations.metrics

Class AbstractHyperLogLog

java.lang.Object

org.elasticsearch.search.aggregations.metrics.AbstractHyperLogLog

public abstract class AbstractHyperLogLog
extends Object

Hyperloglog counter, implemented based on pseudo code from http://static.googleusercontent.com/media/research.google.com/fr//pubs/archive/40671.pdf and its appendix https://docs.google.com/document/d/1gyjfMHy43U9OWBXxfaeG-3MjGzejW1dlpyMwEYAAWEI/view?fullscreen Trying to understand what this class does without having read the paper is considered adventurous.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static interface	AbstractHyperLogLog.RunLenIterator	Iterator over a HyperLogLog register

Field Summary

Fields

Modifier and Type	Field	Description
protected int	m
static int	MAX_PRECISION
static int	MIN_PRECISION
protected int	p

Constructor Summary

Constructors

Constructor	Description
AbstractHyperLogLog(int precision)

Method Summary

Modifier and Type	Method	Description
protected abstract void	addRunLen(long bucketOrd, int register, int runLen)	Add a new runLen to the register.
long	cardinality(long bucketOrd)	Returns the current computed cardinality
void	collect(long bucketOrd, long hash)
void	collectEncoded(long bucketOrd, int encoded)
protected abstract AbstractHyperLogLog.RunLenIterator	getRunLens(long bucketOrd)	Returns an iterator over all values of the register.
int	precision()	Precision of the algorithm

Methods inherited from class java.lang.Object

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

Field Details

m

protected final int m

MIN_PRECISION

public static final int MIN_PRECISION

See Also:

Constant Field Values

MAX_PRECISION

public static final int MAX_PRECISION

See Also:

Constant Field Values

p

protected final int p

Constructor Details

AbstractHyperLogLog

public AbstractHyperLogLog(int precision)

Method Details

addRunLen

protected abstract void addRunLen(long bucketOrd,
 int register,
 int runLen)

Add a new runLen to the register. Implementor should only keep the value if it is bigger that the current value of the register provided.

getRunLens

protected abstract AbstractHyperLogLog.RunLenIterator getRunLens(long bucketOrd)

Returns an iterator over all values of the register.

collect

public void collect(long bucketOrd,
 long hash)

cardinality

public long cardinality(long bucketOrd)

Returns the current computed cardinality

collectEncoded

public void collectEncoded(long bucketOrd,
 int encoded)

precision

public int precision()

Precision of the algorithm