class HClust::IndexPriorityQueue

• HClust::IndexPriorityQueue
• Reference
• Object

Overview

An IndexPriorityQueue is a priority queue of contiguous zero-based indexes.

It supports efficient access to and removal of the element with highest priority (defined as the smallest value). It is designed for optimally searching nearest neighbors (priority = dissimilarity).

It is implemented as a min binary heap (where the top is the minimum element), where the indexes and priorities are also stored separately. Note that deleted indexes are marked as inactive, but otherwise kept in memory. Therefore, indexing is not supported.

Defined in:

hclust/queue.cr

Constructors

• .new(size : Int32, &)

  Creates a new IndexPriorityQueue with indexes in the range [0, size), invoking the given block for each index and setting its priority to the block's return value.

• .new(priorities : Array(Number)) : self

  Creates a new IndexPriorityQueue from the given priorities with indexes in the range [0, priorities.size).

Instance Method Summary

• #empty? : Bool

  Returns true if the queue is empty, else false.

• #first : Int32

  Returns the index with highest priority (smallest value).

• #first? : Int32 | Nil

  Returns the index with highest priority (smallest value), or nil if the queue is empty.

• #pop : Int32 | Nil

  Removes and returns the index with highest priority (smallest value), or nil if the queue is empty.

• #priority_at(index : Int32) : Float64

  Returns the priority of the element at index.

• #set_priority_at(index : Int, priority : Float64) : Nil

  Updates the priority of the element at index with the given value.

• #size : Int32

  Returns the number of indexes in the queue.

• #to_a : Array(Int32)

  Returns the indexes as an array.

Constructor Detail

Instance Method Detail