Package elki.database.query

Class WrappedPrioritySearchDBIDByLookup<O>

java.lang.Object

elki.database.query.WrappedPrioritySearchDBIDByLookup<O>

Type Parameters:

O - relation object type

All Implemented Interfaces:

DBIDIter, DBIDRef, KNNSearcher<DBIDRef>, PrioritySearcher<DBIDRef>, RangeSearcher<DBIDRef>, Iter

Direct Known Subclasses:

WrappedPrioritySearchDBIDByLookup.Linear

public class WrappedPrioritySearchDBIDByLookup<O>
extends java.lang.Object
implements PrioritySearcher<DBIDRef>

Find nearest neighbors by querying with the original object.

Since:

0.8.0

Author:

Erich Schubert

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	WrappedPrioritySearchDBIDByLookup.Linear<O>	Linear scan searcher.

Field Summary

Fields

Modifier and Type	Field	Description
private PrioritySearcher<O>	inner	Inner kNN searcher.
private Relation<? extends O>	relation	Data relation.

Constructor Summary

Constructors

Modifier	Constructor	Description
private	WrappedPrioritySearchDBIDByLookup(Relation<? extends O> relation, PrioritySearcher<O> inner)	Constructor.

Method Summary

Modifier and Type	Method	Description
PrioritySearcher<DBIDRef>	advance()	Moves the iterator forward to the next entry.
double	allLowerBound()	Lower bound for all subsequent instances (that have been completely explored).
double	computeExactDistance()	Compute the exact distance to the current candidate.
PrioritySearcher<DBIDRef>	decreaseCutoff(double threshold)	Decrease the cutoff threshold.
double	getApproximateAccuracy()	Get approximate distance accuracy (if available).
double	getApproximateDistance()	Get approximate distance (if available).
KNNList	getKNN(DBIDRef id, int k)	Get the k nearest neighbors for a particular object.
double	getLowerBound()	Get the lower bound (if available).
ModifiableDoubleDBIDList	getRange(DBIDRef id, double range, ModifiableDoubleDBIDList result)	Get the neighbors for a particular id in a given query range.
double	getUpperBound()	Get the upper bound (if available).
int	internalGetIndex()	Internal only: Get the internal index.
PrioritySearcher<DBIDRef>	search(DBIDRef query)	Start search with a new object.
boolean	valid()	Returns true if the iterator currently points to a valid object.
static <O> PrioritySearcher<DBIDRef>	wrap(Relation<? extends O> relation, PrioritySearcher<O> inner)	Wrap a query, if not null.

Methods inherited from class java.lang.Object

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

Methods inherited from interface elki.database.ids.DBIDIter

addTo

Methods inherited from interface elki.database.ids.DBIDRef

equals, hashCode

Methods inherited from interface elki.database.query.PrioritySearcher

search

Methods inherited from interface elki.database.query.range.RangeSearcher

getRange

Field Detail

relation

private Relation<? extends O> relation

Data relation.

inner

private PrioritySearcher<O> inner

Inner kNN searcher.

Constructor Detail

WrappedPrioritySearchDBIDByLookup

private WrappedPrioritySearchDBIDByLookup(Relation<? extends O> relation,
                                          PrioritySearcher<O> inner)

Constructor.

Parameters:

relation - data relation

inner - inner kNN searcher

Method Detail

getRange

public ModifiableDoubleDBIDList getRange(DBIDRef id,
                                         double range,
                                         ModifiableDoubleDBIDList result)

Description copied from interface: RangeSearcher

Get the neighbors for a particular id in a given query range.

Specified by:

getRange in interface PrioritySearcher<O>

Specified by:

getRange in interface RangeSearcher<O>

Parameters:

id - query object ID

range - Query range

result - Output data structure

Returns:

neighbors

getKNN

public KNNList getKNN(DBIDRef id,
                      int k)

Description copied from interface: KNNSearcher

Get the k nearest neighbors for a particular object.

Specified by:

getKNN in interface KNNSearcher<O>

Specified by:

getKNN in interface PrioritySearcher<O>

Parameters:

id - query object

k - Number of neighbors requested

Returns:

neighbors

search

public PrioritySearcher<DBIDRef> search(DBIDRef query)

Description copied from interface: PrioritySearcher

Start search with a new object.

Specified by:

search in interface PrioritySearcher<O>

Parameters:

query - Query object

Returns:

this, for chaining

advance

public PrioritySearcher<DBIDRef> advance()

Description copied from interface: Iter

Moves the iterator forward to the next entry.

Specified by:

advance in interface DBIDIter

Specified by:

advance in interface Iter

Specified by:

advance in interface PrioritySearcher<O>

Returns:

The iterator itself.

valid

public boolean valid()

Description copied from interface: Iter

Returns true if the iterator currently points to a valid object.

Specified by:

valid in interface Iter

Returns:

a boolean value, whether the position is valid.

decreaseCutoff

public PrioritySearcher<DBIDRef> decreaseCutoff(double threshold)

Description copied from interface: PrioritySearcher

Decrease the cutoff threshold.

The cutoff must not be increased, as the search may have pruned some results automatically.

Specified by:

decreaseCutoff in interface PrioritySearcher<O>

Parameters:

threshold - Threshold parameter

Returns:

this, for chaining

internalGetIndex

public int internalGetIndex()

Description copied from interface: DBIDRef

Internal only: Get the internal index.

NOT FOR PUBLIC USE - ELKI Optimization engine only.

Specified by:

internalGetIndex in interface DBIDRef

Returns:

Internal index

getApproximateDistance

public double getApproximateDistance()

Description copied from interface: PrioritySearcher

Get approximate distance (if available).

Quality guarantees may vary a lot!

Specified by:

getApproximateDistance in interface PrioritySearcher<O>

Returns:

Double.NaN if not valid

getApproximateAccuracy

public double getApproximateAccuracy()

Description copied from interface: PrioritySearcher

Get approximate distance accuracy (if available).

Quality guarantees may vary a lot!

Specified by:

getApproximateAccuracy in interface PrioritySearcher<O>

Returns:

Double.NaN if not valid

getLowerBound

public double getLowerBound()

Description copied from interface: PrioritySearcher

Get the lower bound (if available).

Note: the lower bound is already checked by the cutoff of the priority search, so this is primarily useful for analyzing the search behavior.

Specified by:

getLowerBound in interface PrioritySearcher<O>

Returns:

Double.NaN if not valid

getUpperBound

public double getUpperBound()

Description copied from interface: PrioritySearcher

Get the upper bound (if available).

Specified by:

getUpperBound in interface PrioritySearcher<O>

Returns:

Double.NaN if not valid

computeExactDistance

public double computeExactDistance()

Description copied from interface: PrioritySearcher

Compute the exact distance to the current candidate.

The searcher may or may not have this value already.

Specified by:

computeExactDistance in interface PrioritySearcher<O>

Returns:

Distance

allLowerBound

public double allLowerBound()

Description copied from interface: PrioritySearcher

Lower bound for all subsequent instances (that have been completely explored). The searcher guarantees that no further results will be returned with a distance less than this.

Specified by:

allLowerBound in interface PrioritySearcher<O>

Returns:

lower bound; 0 if no guarantees (e.g., linear scan)

wrap

public static <O> PrioritySearcher<DBIDRef> wrap(Relation<? extends O> relation,
                                                 PrioritySearcher<O> inner)

Wrap a query, if not null.

Type Parameters:

O - inner data type

Parameters:

relation - Relation to get object from

inner - inner query

Returns:

wrapped query, or null if inner was null