Package org.apache.lucene.codecs.lucene94

Class Lucene94HnswVectorsReader

java.lang.Object

org.apache.lucene.codecs.KnnVectorsReader

org.apache.lucene.codecs.lucene94.Lucene94HnswVectorsReader

All Implemented Interfaces:

Closeable, AutoCloseable, Accountable

public final class Lucene94HnswVectorsReader
extends KnnVectorsReader

Reads vectors from the index segments along with index data structures supporting KNN search.

WARNING: This API is experimental and might change in incompatible ways in the next release.

Field Summary

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

NULL_ACCOUNTABLE

Method Summary

Modifier and Type	Method	Description
void	checkIntegrity()	Checks consistency of this reader.
void	close()
HnswGraph	getGraph(String field)	Get knn graph values; used for testing
VectorValues	getVectorValues(String field)	Returns the VectorValues for the given field.
long	ramBytesUsed()	Return the memory usage of this object in bytes.
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 org.apache.lucene.codecs.KnnVectorsReader

getMergeInstance

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

Method Detail

ramBytesUsed

public long ramBytesUsed()

Description copied from interface: Accountable

Return the memory usage of this object in bytes. Negative values are illegal.

checkIntegrity

public void checkIntegrity()
                    throws IOException

Description copied from class: KnnVectorsReader

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.

Specified by:

checkIntegrity in class KnnVectorsReader

Throws:

IOException

getVectorValues

public VectorValues getVectorValues(String field)
                             throws IOException

Description copied from class: KnnVectorsReader

Returns the VectorValues 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.

Specified by:

getVectorValues in class KnnVectorsReader

Throws:

IOException

search

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

Description copied from class: KnnVectorsReader

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.

Specified by:

search in class KnnVectorsReader

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

getGraph

public HnswGraph getGraph(String field)
                   throws IOException

Get knn graph values; used for testing

Throws:

IOException

close

public void close()
           throws IOException

Throws:

IOException