Package elki.index.vafile

Class PartialVAFile.PartialVAFileKNNQuery

java.lang.Object

elki.index.AbstractRefiningIndex.AbstractRefiningQuery

elki.index.vafile.PartialVAFile.PartialVAFileKNNQuery

All Implemented Interfaces:

KNNSearcher<V>

Enclosing class:

PartialVAFile<V extends NumberVector>

public class PartialVAFile.PartialVAFileKNNQuery
extends AbstractRefiningIndex.AbstractRefiningQuery
implements KNNSearcher<V>

KNN query for this index.

Author:

Erich Schubert, Thomas Bernecker

Field Summary

Fields

Modifier and Type	Field	Description
private double	p	Lp-Norm p.
private long[]	subspace	Subspace.

Fields inherited from class elki.index.AbstractRefiningIndex.AbstractRefiningQuery

distanceQuery

Constructor Summary

Constructors

Constructor	Description
PartialVAFileKNNQuery(DistanceQuery<V> ddq, double p, long[] subspace)	Constructor.

Method Summary

Modifier and Type	Method	Description
private java.util.LinkedList<PartialVAFile.PartialVACandidate>	filter1(int k, int reducedDims, java.util.List<DAFile> daFiles, VectorApproximation queryApprox, int subspaceDims, VALPNormDistance dist)
private int	getIOCosts(int size, int subspaceDims)	Computes IO costs (in bytes) needed for refining the candidates.
private int	getIOCosts(DAFile sample, int numberOfDAFiles)	Computes IO costs (in bytes) needed for reading several DA-files.
KNNList	getKNN(V query, int k)	Get the k nearest neighbors for a particular object.
java.util.List<DAFile>	getWorstCaseDistOrder(VALPNormDistance dist, long[] subspace)	Order subspaces by their worst case distance.
protected KNNList	retrieveAccurateDistances(java.util.List<PartialVAFile.PartialVACandidate> sortedCandidates, int k, long[] subspace, V query)

Methods inherited from class elki.index.AbstractRefiningIndex.AbstractRefiningQuery

incRefinements, refine

Methods inherited from class java.lang.Object

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

Field Detail

p

private double p

Lp-Norm p.

subspace

private long[] subspace

Subspace.

Constructor Detail

PartialVAFileKNNQuery

public PartialVAFileKNNQuery(DistanceQuery<V> ddq,
                             double p,
                             long[] subspace)

Constructor.

Parameters:

ddq - Distance query

p - LP-norm p

subspace - Subspace to query

Method Detail

getKNN

public KNNList getKNN(V query,
                      int k)

Description copied from interface: KNNSearcher

Get the k nearest neighbors for a particular object.

Specified by:

getKNN in interface KNNSearcher<V extends NumberVector>

Parameters:

query - query object

k - Number of neighbors requested

Returns:

neighbors

filter1

private java.util.LinkedList<PartialVAFile.PartialVACandidate> filter1(int k,
                                                                       int reducedDims,
                                                                       java.util.List<DAFile> daFiles,
                                                                       VectorApproximation queryApprox,
                                                                       int subspaceDims,
                                                                       VALPNormDistance dist)

getIOCosts

private int getIOCosts(int size,
                       int subspaceDims)

Computes IO costs (in bytes) needed for refining the candidates.

Parameters:

size - The nuber of candidates

subspaceDims - the required subspace dimensions

Returns:

the cost value (in bytes)

getIOCosts

private int getIOCosts(DAFile sample,
                       int numberOfDAFiles)

Computes IO costs (in bytes) needed for reading several DA-files.

Parameters:

sample - the DA-file specific costs

numberOfDAFiles - the number of DA-files that have to be read

Returns:

the cost value (in bytes)

getWorstCaseDistOrder

public java.util.List<DAFile> getWorstCaseDistOrder(VALPNormDistance dist,
                                                    long[] subspace)

Order subspaces by their worst case distance.

Parameters:

dist - Distance function

subspace - Subspace

Returns:

Ordered list of dimension files

retrieveAccurateDistances

protected KNNList retrieveAccurateDistances(java.util.List<PartialVAFile.PartialVACandidate> sortedCandidates,
                                            int k,
                                            long[] subspace,
                                            V query)