Class Lucene90OnHeapHnswGraph

java.lang.Object
org.apache.lucene.util.hnsw.HnswGraph
org.apache.lucene.backward_codecs.lucene90.Lucene90OnHeapHnswGraph

public final class Lucene90OnHeapHnswGraph extends HnswGraph
An HnswGraph where all nodes and connections are held in memory. This class is used to construct the HNSW graph before it's written to the index.
  • Field Details

  • Constructor Details

    • Lucene90OnHeapHnswGraph

      Lucene90OnHeapHnswGraph(int maxConn)
  • Method Details

    • search

      public static NeighborQueue search(float[] query, int topK, int numSeed, RandomAccessVectorValues vectors, VectorSimilarityFunction similarityFunction, HnswGraph graphValues, Bits acceptOrds, int visitedLimit, SplittableRandom random) throws IOException
      Searches for the nearest neighbors of a query vector.
      Parameters:
      query - search query vector
      topK - the number of nodes to be returned
      numSeed - the size of the queue maintained while searching, and controls the number of random entry points to sample
      vectors - vector values
      graphValues - the graph values. May represent the entire graph, or a level in a hierarchical graph.
      acceptOrds - Bits that represents the allowed document ordinals to match, or null if they are all allowed to match.
      random - a source of randomness, used for generating entry points to the graph
      Returns:
      a priority queue holding the closest neighbors found
      Throws:
      IOException
    • getNeighbors

      public Lucene90NeighborArray getNeighbors(int node)
      Returns the NeighborQueue connected to the given node.
      Parameters:
      node - the node whose neighbors are returned
    • size

      public int size()
      Description copied from class: HnswGraph
      Returns the number of nodes in the graph
      Specified by:
      size in class HnswGraph
    • addNode

      int addNode()
    • seek

      public void seek(int level, int targetNode)
      Description copied from class: HnswGraph
      Move the pointer to exactly the given level's target. After this method returns, call HnswGraph.nextNeighbor() to return successive (ordered) connected node ordinals.
      Specified by:
      seek in class HnswGraph
      Parameters:
      level - level of the graph
      targetNode - ordinal of a node in the graph, must be ≥ 0 and < VectorValues.size().
    • nextNeighbor

      public int nextNeighbor()
      Description copied from class: HnswGraph
      Iterates over the neighbor list. It is illegal to call this method after it returns NO_MORE_DOCS without calling HnswGraph.seek(int, int), which resets the iterator.
      Specified by:
      nextNeighbor in class HnswGraph
      Returns:
      a node ordinal in the graph, or NO_MORE_DOCS if the iteration is complete.
    • numLevels

      public int numLevels()
      Description copied from class: HnswGraph
      Returns the number of levels of the graph
      Specified by:
      numLevels in class HnswGraph
    • entryNode

      public int entryNode()
      Description copied from class: HnswGraph
      Returns graph's entry point on the top level *
      Specified by:
      entryNode in class HnswGraph
    • getNodesOnLevel

      public HnswGraph.NodesIterator getNodesOnLevel(int level)
      Description copied from class: HnswGraph
      Get all nodes on a given level as node 0th ordinals
      Specified by:
      getNodesOnLevel in class HnswGraph
      Parameters:
      level - level for which to get all nodes
      Returns:
      an iterator over nodes where nextInt returns a next node on the level