Package org.apache.lucene.util.hnsw

Class OnHeapHnswGraph

  • public final class OnHeapHnswGraph
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.

    • Method Detail

      • getNeighbors

        public NeighborArray getNeighbors​(int level,
                                  int node)
        Returns the NeighborQueue connected to the given node.
        Parameters:
        level - level of the graph
        node - the node whose neighbors are returned, represented as an ordinal on the level 0.

      • size

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

      • addNode

        public void addNode​(int level,
                    int node)
        Add node on the given level
        Parameters:
        level - level to add a node on
        node - the node to add, represented as an ordinal on the level 0.

      • 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()
        Returns the current number of levels in the graph
        Specified by:
        numLevels in class HnswGraph
        Returns:
        the current number of levels in the graph

      • entryNode

        public int entryNode()
        Returns the graph's current entry node on the top level shown as ordinals of the nodes on 0th level
        Specified by:
        entryNode in class HnswGraph
        Returns:
        the graph's current entry node on the top level

      • 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