Package elki.index.preprocessed.snn

Class SharedNearestNeighborPreprocessor<O>

java.lang.Object

elki.index.preprocessed.snn.SharedNearestNeighborPreprocessor<O>

Type Parameters:

O - the type of database objects the preprocessor can be applied to

All Implemented Interfaces:

Index, SharedNearestNeighborIndex<O>

@Title("Shared Nearest Neighbor Preprocessor")
@Description("Computes the k nearest neighbors of objects of a certain database.")
public class SharedNearestNeighborPreprocessor<O>
extends java.lang.Object
implements SharedNearestNeighborIndex<O>

A preprocessor for annotation of the ids of nearest neighbors to each database object.

The k nearest neighbors are assigned based on an arbitrary distance function.

This functionality is similar but not identical to MaterializeKNNPreprocessor: While it also computes the k nearest neighbors, it does not keep the actual distances, but organizes the NN set in a TreeSet for fast set operations.

Since:

0.1

Author:

Arthur Zimek, Erich Schubert

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	SharedNearestNeighborPreprocessor.Factory<O>	Factory class

Field Summary

Fields

Modifier and Type	Field	Description
protected Distance<O>	distance	Hold the distance function to be used.
private static Logging	LOG	Get a logger for this class.
protected int	numberOfNeighbors	Holds the number of nearest neighbors to be used.
protected Relation<O>	relation	Relation to use.
protected WritableDataStore<ArrayDBIDs>	storage	The data store.

Constructor Summary

Constructors

Constructor	Description
SharedNearestNeighborPreprocessor(Relation<O> relation, int numberOfNeighbors, Distance<O> distance)	Constructor.

Method Summary

Modifier and Type	Method	Description
ArrayDBIDs	getNearestNeighborSet(DBIDRef objid)	Get the precomputed nearest neighbors
int	getNumberOfNeighbors()	Get the number of neighbors
void	initialize()	Initialize the index.

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

Field Detail

LOG

private static final Logging LOG

Get a logger for this class.

numberOfNeighbors

protected int numberOfNeighbors

Holds the number of nearest neighbors to be used.

distance

protected Distance<O> distance

Hold the distance function to be used.

storage

protected WritableDataStore<ArrayDBIDs> storage

The data store.

relation

protected Relation<O> relation

Relation to use.

Constructor Detail

SharedNearestNeighborPreprocessor

public SharedNearestNeighborPreprocessor(Relation<O> relation,
                                         int numberOfNeighbors,
                                         Distance<O> distance)

Constructor.

Parameters:

relation - Database to use

numberOfNeighbors - Number of neighbors

distance - Distance function

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

getNearestNeighborSet

public ArrayDBIDs getNearestNeighborSet(DBIDRef objid)

Description copied from interface: SharedNearestNeighborIndex

Get the precomputed nearest neighbors

Specified by:

getNearestNeighborSet in interface SharedNearestNeighborIndex<O>

Parameters:

objid - Object ID

Returns:

Neighbor DBIDs

getNumberOfNeighbors

public int getNumberOfNeighbors()

Get the number of neighbors

Specified by:

getNumberOfNeighbors in interface SharedNearestNeighborIndex<O>

Returns:

NN size