Class FlatVectorsReader

java.lang.Object
org.apache.lucene.codecs.KnnVectorsReader
org.apache.lucene.codecs.hnsw.FlatVectorsReader
All Implemented Interfaces:
Closeable, AutoCloseable, Accountable
Direct Known Subclasses:
Lucene99FlatVectorsReader, Lucene99ScalarQuantizedVectorsReader

public abstract class FlatVectorsReader extends KnnVectorsReader implements Accountable
Reads vectors from an index. When searching this reader, it iterates every vector in the index and scores them

This class is useful when:

  • the number of vectors is small
  • when used along side some additional indexing structure that can be used to better search the vectors (like HNSW).
WARNING: This API is experimental and might change in incompatible ways in the next release.
  • Field Details

    • vectorScorer

      protected final FlatVectorsScorer vectorScorer
      Scorer for flat vectors
  • Constructor Details

    • FlatVectorsReader

      protected FlatVectorsReader(FlatVectorsScorer vectorsScorer)
      Sole constructor
  • Method Details

    • getFlatVectorScorer

      public FlatVectorsScorer getFlatVectorScorer()
      Returns:
      the FlatVectorsScorer for this reader.
    • search

      public void search(String field, float[] target, KnnCollector knnCollector, Bits acceptDocs) 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
      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 void search(String field, byte[] target, KnnCollector knnCollector, Bits acceptDocs) 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
      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
    • getRandomVectorScorer

      public abstract RandomVectorScorer getRandomVectorScorer(String field, float[] target) throws IOException
      Returns a RandomVectorScorer for the given field and target vector.
      Parameters:
      field - the field to search
      target - the target vector
      Returns:
      a RandomVectorScorer for the given field and target vector.
      Throws:
      IOException - if an I/O error occurs when reading from the index.
    • getRandomVectorScorer

      public abstract RandomVectorScorer getRandomVectorScorer(String field, byte[] target) throws IOException
      Returns a RandomVectorScorer for the given field and target vector.
      Parameters:
      field - the field to search
      target - the target vector
      Returns:
      a RandomVectorScorer for the given field and target vector.
      Throws:
      IOException - if an I/O error occurs when reading from the index.