Package org.apache.lucene.codecs

Class KnnVectorsReader

java.lang.Object
org.apache.lucene.codecs.KnnVectorsReader
All Implemented Interfaces:
Closeable, AutoCloseable, Accountable
Direct Known Subclasses:
Lucene99HnswVectorsReader, PerFieldKnnVectorsFormat.FieldsReader
public abstract class KnnVectorsReader extends Object implements Closeable, Accountable
Reads vectors from an index.

  • Constructor Details

    • KnnVectorsReader

      protected KnnVectorsReader()
      Sole constructor

  • Method Details

    • 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 void search(String field, float[] target, KnnCollector knnCollector, Bits acceptDocs) 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
      knnCollector - a KnnResults collector and relevant settings for gathering vector results
      acceptDocs - Bits that represents the allowed documents to match, or null if they are all allowed to match.
      Throws:
      IOException

    • search

      public abstract void search(String field, byte[] target, KnnCollector knnCollector, Bits acceptDocs) 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
      knnCollector - a KnnResults collector and relevant settings for gathering vector results
      acceptDocs - Bits that represents the allowed documents to match, or null if they are all allowed to match.
      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