de.lmu.ifi.dbs.elki.index.vafile

Class PartialVAFile.PartialVAFileKNNQuery

java.lang.Object

de.lmu.ifi.dbs.elki.database.query.knn.AbstractDistanceKNNQuery<O>

de.lmu.ifi.dbs.elki.index.AbstractRefiningIndex.AbstractKNNQuery

de.lmu.ifi.dbs.elki.index.vafile.PartialVAFile.PartialVAFileKNNQuery

All Implemented Interfaces:

DatabaseQuery, KNNQuery<V>

Enclosing class:

PartialVAFile<V extends NumberVector>

public class PartialVAFile.PartialVAFileKNNQuery
extends AbstractRefiningIndex.AbstractKNNQuery

KNN query for this index.

Author:

Erich Schubert, Thomas Bernecker

Field Summary

Fields

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

Fields inherited from class de.lmu.ifi.dbs.elki.database.query.knn.AbstractDistanceKNNQuery

distanceQuery

Fields inherited from interface de.lmu.ifi.dbs.elki.database.query.DatabaseQuery

HINT_BULK, HINT_EXACT, HINT_HEAVY_USE, HINT_NO_CACHE, HINT_OPTIMIZED_ONLY, HINT_SINGLE

Constructor Summary

Constructors

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

Method Summary

Modifier and Type	Method and 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(DAFile sample, int numberOfDAFiles) Computes IO costs (in bytes) needed for reading several DA-files.
private int	getIOCosts(int size, int subspaceDims) Computes IO costs (in bytes) needed for refining the candidates.
KNNList	getKNNForObject(V query, int k) Get the k nearest neighbors for a particular id.
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 de.lmu.ifi.dbs.elki.index.AbstractRefiningIndex.AbstractKNNQuery

incRefinements, refine

Methods inherited from class de.lmu.ifi.dbs.elki.database.query.knn.AbstractDistanceKNNQuery

getKNNForBulkDBIDs, getKNNForDBID, getRelation

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

getKNNForObject

public KNNList getKNNForObject(V query,
                               int k)

Description copied from interface: KNNQuery

Get the k nearest neighbors for a particular id.

Specified by:

getKNNForObject in interface KNNQuery<V extends NumberVector>

Specified by:

getKNNForObject in class AbstractDistanceKNNQuery<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)