Class KnnVectorsReader

    • 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.

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

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