Package elki.index.lsh

Class InMemoryLSHIndex.Instance

java.lang.Object

elki.index.AbstractRefiningIndex<V>

elki.index.lsh.InMemoryLSHIndex.Instance

All Implemented Interfaces:

Index, KNNIndex<V>, RangeIndex<V>

Enclosing class:

InMemoryLSHIndex<V>

public class InMemoryLSHIndex.Instance
extends AbstractRefiningIndex<V>
implements KNNIndex<V>, RangeIndex<V>

Instance of a LSH index for a single relation.

Author:

Erich Schubert

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
protected class	InMemoryLSHIndex.Instance.LSHKNNQuery	Class for handling kNN queries against the LSH index.
protected class	InMemoryLSHIndex.Instance.LSHRangeQuery	Class for handling kNN queries against the LSH index.

Nested classes/interfaces inherited from class elki.index.AbstractRefiningIndex

AbstractRefiningIndex.AbstractRefiningQuery

Field Summary

Fields

Modifier and Type	Field	Description
(package private) java.util.ArrayList<? extends LocalitySensitiveHashFunction<? super V>>	hashfunctions	Hash functions to use.
(package private) java.util.ArrayList<it.unimi.dsi.fastutil.ints.Int2ObjectOpenHashMap<DBIDs>>	hashtables	The actual table
private int	numberOfBuckets	Number of buckets to use.

Fields inherited from class elki.index.AbstractRefiningIndex

relation

Constructor Summary

Constructors

Constructor	Description
Instance(Relation<V> relation, java.util.ArrayList<? extends LocalitySensitiveHashFunction<? super V>> hashfunctions, int numberOfBuckets)	Constructor.

Method Summary

Modifier and Type	Method	Description
protected DBIDs	getCandidates(V obj)	Get the candidates: points which have at least one hash bucket in common.
Logging	getLogger()	Get the class logger.
void	initialize()	Initialize the index.
KNNSearcher<V>	kNNByObject(DistanceQuery<V> distanceQuery, int maxk, int flags)	Get a KNN query object for the given distance query and k.
RangeSearcher<V>	rangeByObject(DistanceQuery<V> distanceQuery, double maxradius, int flags)	Get a range query object for the given distance query and k.

Methods inherited from class elki.index.AbstractRefiningIndex

countRefinements, logStatistics, refine

Methods inherited from class java.lang.Object

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

Methods inherited from interface elki.index.Index

logStatistics

Methods inherited from interface elki.index.KNNIndex

kNNByDBID

Methods inherited from interface elki.index.RangeIndex

rangeByDBID

Field Detail

hashfunctions

java.util.ArrayList<? extends LocalitySensitiveHashFunction<? super V>> hashfunctions

Hash functions to use.

hashtables

java.util.ArrayList<it.unimi.dsi.fastutil.ints.Int2ObjectOpenHashMap<DBIDs>> hashtables

The actual table

numberOfBuckets

private int numberOfBuckets

Number of buckets to use.

Constructor Detail

Instance

public Instance(Relation<V> relation,
                java.util.ArrayList<? extends LocalitySensitiveHashFunction<? super V>> hashfunctions,
                int numberOfBuckets)

Constructor.

Parameters:

relation - Relation to index.

hashfunctions - Hash functions.

Method Detail

initialize

public void initialize()

Description copied from interface: Index

Initialize the index. For static indexes, this is the moment the index is bulk loaded.

Specified by:

initialize in interface Index

getLogger

public Logging getLogger()

Description copied from class: AbstractRefiningIndex

Get the class logger.

Specified by:

getLogger in class AbstractRefiningIndex<V>

Returns:

Logger

kNNByObject

public KNNSearcher<V> kNNByObject(DistanceQuery<V> distanceQuery,
                                  int maxk,
                                  int flags)

Description copied from interface: KNNIndex

Get a KNN query object for the given distance query and k.

This function MAY return null, when the given distance is not supported!

Specified by:

kNNByObject in interface KNNIndex<V>

Parameters:

distanceQuery - Distance query

maxk - Maximum value of k

flags - Hints for the optimizer

Returns:

KNN Query object or null

rangeByObject

public RangeSearcher<V> rangeByObject(DistanceQuery<V> distanceQuery,
                                      double maxradius,
                                      int flags)

Description copied from interface: RangeIndex

Get a range query object for the given distance query and k.

This function MAY return null, when the given distance is not supported!

Specified by:

rangeByObject in interface RangeIndex<V>

Parameters:

distanceQuery - Distance query

maxradius - Maximum range

flags - Hints for the optimizer

Returns:

KNN Query object or null

getCandidates

protected DBIDs getCandidates(V obj)

Get the candidates: points which have at least one hash bucket in common.

Parameters:

obj - Query object

Returns:

Candidates