Package org.apache.lucene.search

Class KnnFloatVectorQuery

  • Direct Known Subclasses:
    KnnVectorQuery
    public class KnnFloatVectorQuery
extends Query
    Uses KnnVectorsReader.search(String, float[], int, Bits, int) to perform nearest neighbour search.

    This query also allows for performing a kNN search subject to a filter. In this case, it first executes the filter for each leaf, then chooses a strategy dynamically:

    • If the filter cost is less than k, just execute an exact search
    • Otherwise run a kNN search subject to the filter
    • If the kNN search visits too many vectors without completing, stop and run an exact search

    • Field Detail

      • field

        protected final String field

      • k

        protected final int k

    • Constructor Detail

      • KnnFloatVectorQuery

        public KnnFloatVectorQuery​(String field,
                           float[] target,
                           int k)
        Find the k nearest documents to the target vector according to the vectors in the given field. target vector.
        Parameters:
        field - a field that has been indexed as a KnnFloatVectorField.
        target - the target of the search
        k - the number of documents to find
        Throws:
        IllegalArgumentException - if k is less than 1

      • KnnFloatVectorQuery

        public KnnFloatVectorQuery​(String field,
                           float[] target,
                           int k,
                           Query filter)
        Find the k nearest documents to the target vector according to the vectors in the given field. target vector.
        Parameters:
        field - a field that has been indexed as a KnnFloatVectorField.
        target - the target of the search
        k - the number of documents to find
        filter - a filter applied before the vector search
        Throws:
        IllegalArgumentException - if k is less than 1

    • Method Detail

      • toString

        public String toString​(String field)
        Description copied from class: Query
        Prints a query to a string, with field assumed to be the default field and omitted.
        Specified by:
        toString in class Query

      • equals

        public boolean equals​(Object o)
        Description copied from class: Query
        Override and implement query instance equivalence properly in a subclass. This is required so that QueryCache works properly.

        Typically a query will be equal to another only if it's an instance of the same class and its document-filtering properties are identical that other instance. Utility methods are provided for certain repetitive code.

        See Also:
        Query.sameClassAs(Object), Query.classHash()

      • hashCode

        public int hashCode()
        Description copied from class: Query
        Override and implement query hash code properly in a subclass. This is required so that QueryCache works properly.
        See Also:
        Query.equals(Object)

      • getTargetCopy

        public float[] getTargetCopy()
        Returns:
        the target query vector of the search. Each vector element is a float.

      • rewrite

        public Query rewrite​(IndexReader reader)
              throws IOException
        Description copied from class: Query
        Expert: called to re-write queries into primitive queries. For example, a PrefixQuery will be rewritten into a BooleanQuery that consists of TermQuerys.

        Callers are expected to call rewrite multiple times if necessary, until the rewritten query is the same as the original query.

        Overrides:
        rewrite in class Query
        Throws:
        IOException
        See Also:
        IndexSearcher.rewrite(Query)

      • visit

        public void visit​(QueryVisitor visitor)
        Description copied from class: Query
        Recurse through the query tree, visiting any child queries
        Specified by:
        visit in class Query
        Parameters:
        visitor - a QueryVisitor to be called by each query in the tree

      • getField

        public String getField()
        Returns:
        the knn vector field where the knn vector search happens.

      • getK

        public int getK()
        Returns:
        the max number of results the KnnVector search returns.

      • getFilter

        public Query getFilter()
        Returns:
        the filter that is executed before the KnnVector search happens. Only the results accepted by this filter are returned by the KnnVector search.