de.lmu.ifi.dbs.elki.index.preprocessed.snn

Class SharedNearestNeighborPreprocessor<O>

java.lang.Object

de.lmu.ifi.dbs.elki.index.preprocessed.AbstractPreprocessorIndex<O,ArrayDBIDs>

de.lmu.ifi.dbs.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>, Result

@Title(value="Shared Nearest Neighbor Preprocessor")
 @Description(value="Computes the k nearest neighbors of objects of a certain database.")
public class SharedNearestNeighborPreprocessor<O>
extends AbstractPreprocessorIndex<O,ArrayDBIDs>
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 and Description
static class	SharedNearestNeighborPreprocessor.Factory<O> Factory class

Field Summary

Fields

Modifier and Type	Field and Description
protected DistanceFunction<O>	distanceFunction 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.

Fields inherited from class de.lmu.ifi.dbs.elki.index.preprocessed.AbstractPreprocessorIndex

relation, storage

Constructor Summary

Constructors

Constructor and Description
SharedNearestNeighborPreprocessor(Relation<O> relation, int numberOfNeighbors, DistanceFunction<O> distanceFunction) Constructor.

Method Summary

Modifier and Type	Method and Description
protected Logging	getLogger() Get the classes static logger.
java.lang.String	getLongName() A "pretty" name for the result, for use in titles, captions and menus.
ArrayDBIDs	getNearestNeighborSet(DBIDRef objid) Get the precomputed nearest neighbors
int	getNumberOfNeighbors() Get the number of neighbors
java.lang.String	getShortName() A short name for the result, useful for file names.
void	initialize() Initialize the index.
void	logStatistics() Send statistics to the logger, if enabled.

Methods inherited from class java.lang.Object

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

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.

distanceFunction

protected DistanceFunction<O> distanceFunction

Hold the distance function to be used.

Constructor Detail

SharedNearestNeighborPreprocessor

public SharedNearestNeighborPreprocessor(Relation<O> relation,
                                         int numberOfNeighbors,
                                         DistanceFunction<O> distanceFunction)

Constructor.

Parameters:

relation - Database to use

numberOfNeighbors - Number of neighbors

distanceFunction - 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

getLogger

protected Logging getLogger()

Description copied from class: AbstractPreprocessorIndex

Get the classes static logger.

Specified by:

getLogger in class AbstractPreprocessorIndex<O,ArrayDBIDs>

Returns:

Logger

getLongName

public java.lang.String getLongName()

Description copied from interface: Result

A "pretty" name for the result, for use in titles, captions and menus.

Specified by:

getLongName in interface Result

Returns:

result name

getShortName

public java.lang.String getShortName()

Description copied from interface: Result

A short name for the result, useful for file names.

Specified by:

getShortName in interface Result

Returns:

result name

logStatistics

public void logStatistics()

Description copied from interface: Index

Send statistics to the logger, if enabled. Note: you must have set the logging level appropriately before initializing the index! Otherwise, the index might not have collected the desired statistics.

Specified by:

logStatistics in interface Index

getNumberOfNeighbors

public int getNumberOfNeighbors()

Get the number of neighbors

Specified by:

getNumberOfNeighbors in interface SharedNearestNeighborIndex<O>

Returns:

NN size