Package org.apache.lucene.util.hnsw

Class NeighborQueue

  • public class NeighborQueue
extends Object
    NeighborQueue uses a LongHeap to store lists of arcs in an HNSW graph, represented as a neighbor node id with an associated score packed together as a sortable long, which is sorted primarily by score. The queue provides both fixed-size and unbounded operations via insertWithOverflow(int, float) and add(int, float), and provides MIN and MAX heap subclasses.

    • Constructor Detail

      • NeighborQueue

        public NeighborQueue​(int initialSize,
                     boolean maxHeap)

    • Method Detail

      • size

        public int size()
        Returns:
        the number of elements in the heap

      • add

        public void add​(int newNode,
                float newScore)
        Adds a new graph arc, extending the storage as needed.
        Parameters:
        newNode - the neighbor node id
        newScore - the score of the neighbor, relative to some other node

      • insertWithOverflow

        public boolean insertWithOverflow​(int newNode,
                                  float newScore)
        If the heap is not full (size is less than the initialSize provided to the constructor), adds a new node-and-score element. If the heap is full, compares the score against the current top score, and replaces the top element if newScore is better than (greater than unless the heap is reversed), the current top score.
        Parameters:
        newNode - the neighbor node id
        newScore - the score of the neighbor, relative to some other node

      • pop

        public int pop()
        Removes the top element and returns its node id.

      • nodes

        public int[] nodes()

      • topNode

        public int topNode()
        Returns the top element's node id.

      • topScore

        public float topScore()
        Returns the top element's node score. For the min heap this is the minimum score. For the max heap this is the maximum score.

      • clear

        public void clear()

      • visitedCount

        public int visitedCount()

      • setVisitedCount

        public void setVisitedCount​(int visitedCount)

      • incomplete

        public boolean incomplete()

      • markIncomplete

        public void markIncomplete()