Package org.apache.lucene.codecs

Class KnnVectorsReader

java.lang.Object

org.apache.lucene.codecs.KnnVectorsReader

All Implemented Interfaces:

Closeable, AutoCloseable, Accountable

Direct Known Subclasses:

Lucene95HnswVectorsReader, PerFieldKnnVectorsFormat.FieldsReader

public abstract class KnnVectorsReader
extends Object
implements Closeable, Accountable

Reads vectors from an index.

Field Summary

Fields inherited from interface org.apache.lucene.util.Accountable

NULL_ACCOUNTABLE

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	KnnVectorsReader()	Sole constructor

Method Summary

Modifier and Type	Method	Description
abstract void	checkIntegrity()	Checks consistency of this reader.
abstract ByteVectorValues	getByteVectorValues(String field)	Returns the ByteVectorValues for the given field.
abstract FloatVectorValues	getFloatVectorValues(String field)	Returns the FloatVectorValues for the given field.
KnnVectorsReader	getMergeInstance()	Returns an instance optimized for merging.
abstract TopDocs	search(String field, byte[] target, int k, Bits acceptDocs, int visitedLimit)	Return the k nearest neighbor documents as determined by comparison of their vector values for this field, to the given vector, by the field's similarity function.
abstract TopDocs	search(String field, float[] target, int k, Bits acceptDocs, int visitedLimit)	Return the k nearest neighbor documents as determined by comparison of their vector values for this field, to the given vector, by the field's similarity function.

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.apache.lucene.util.Accountable

getChildResources, ramBytesUsed

Methods inherited from interface java.io.Closeable

close

Constructor Detail

KnnVectorsReader

protected KnnVectorsReader()

Sole constructor

Method Detail

checkIntegrity

public abstract void checkIntegrity()
                             throws IOException

Checks consistency of this reader.

Note that this may be costly in terms of I/O, e.g. may involve computing a checksum value against large data files.

Throws:

IOException

NOTE: This API is for internal purposes only and might change in incompatible ways in the next release.

getFloatVectorValues

public abstract FloatVectorValues getFloatVectorValues(String field)
                                                throws IOException

Returns the FloatVectorValues for the given field. The behavior is undefined if the given field doesn't have KNN vectors enabled on its FieldInfo. The return value is never null.

Throws:

IOException

getByteVectorValues

public abstract ByteVectorValues getByteVectorValues(String field)
                                              throws IOException

Returns the ByteVectorValues for the given field. The behavior is undefined if the given field doesn't have KNN vectors enabled on its FieldInfo. The return value is never null.

Throws:

IOException

search

public abstract TopDocs search(String field,
                               float[] target,
                               int k,
                               Bits acceptDocs,
                               int visitedLimit)
                        throws IOException

Return the k nearest neighbor documents as determined by comparison of their vector values for this field, to the given vector, by the field's similarity function. The score of each document is derived from the vector similarity in a way that ensures scores are positive and that a larger score corresponds to a higher ranking.

The search is allowed to be approximate, meaning the results are not guaranteed to be the true k closest neighbors. For large values of k (for example when k is close to the total number of documents), the search may also retrieve fewer than k documents.

The returned TopDocs will contain a ScoreDoc for each nearest neighbor, in order of their similarity to the query vector (decreasing scores). The TotalHits contains the number of documents visited during the search. If the search stopped early because it hit visitedLimit, it is indicated through the relation TotalHits.Relation.GREATER_THAN_OR_EQUAL_TO.

The behavior is undefined if the given field doesn't have KNN vectors enabled on its FieldInfo. The return value is never null.

Parameters:

field - the vector field to search

target - the vector-valued query

k - the number of docs to return

acceptDocs - Bits that represents the allowed documents to match, or null if they are all allowed to match.

visitedLimit - the maximum number of nodes that the search is allowed to visit

Returns:

the k nearest neighbor documents, along with their (similarity-specific) scores.

Throws:

IOException

search

public abstract TopDocs search(String field,
                               byte[] target,
                               int k,
                               Bits acceptDocs,
                               int visitedLimit)
                        throws IOException

Return the k nearest neighbor documents as determined by comparison of their vector values for this field, to the given vector, by the field's similarity function. The score of each document is derived from the vector similarity in a way that ensures scores are positive and that a larger score corresponds to a higher ranking.

The search is allowed to be approximate, meaning the results are not guaranteed to be the true k closest neighbors. For large values of k (for example when k is close to the total number of documents), the search may also retrieve fewer than k documents.

The returned TopDocs will contain a ScoreDoc for each nearest neighbor, in order of their similarity to the query vector (decreasing scores). The TotalHits contains the number of documents visited during the search. If the search stopped early because it hit visitedLimit, it is indicated through the relation TotalHits.Relation.GREATER_THAN_OR_EQUAL_TO.

The behavior is undefined if the given field doesn't have KNN vectors enabled on its FieldInfo. The return value is never null.

Parameters:

field - the vector field to search

target - the vector-valued query

k - the number of docs to return

acceptDocs - Bits that represents the allowed documents to match, or null if they are all allowed to match.

visitedLimit - the maximum number of nodes that the search is allowed to visit

Returns:

the k nearest neighbor documents, along with their (similarity-specific) scores.

Throws:

IOException

getMergeInstance

public KnnVectorsReader getMergeInstance()

Returns an instance optimized for merging. This instance may only be consumed in the thread that called getMergeInstance().

The default implementation returns this