kephale / clj-kdtree

kd-trees in Clojure

clj-kdtree

Overview

A Kd-tree is a special type of binary tree that partitions points in a k-dimensional space. It can be used for efficient nearest-neighbor searches.

For more detail, refer to Wikipedia on Kd-trees.

Usage

(require 'kdtree)

(def points [[8 8] [3 1] [6 6] [7 7] [1 3] [4 4] [5 5]])
;; Build a kdtree from a set of points
(def tree (kdtree/build-tree points))
(println "Tree:" tree)

;; Use tree to find neighbors for one point given a set of points.
(println "\n\nFour points closest to [2 2]:\n"
         (kdtree/nearest-neighbor tree [2 2] 4))

;; Same operation, but delete two of the closest points.
(println "\n\nFour points with deletion:\n"
         (kdtree/nearest-neighbor
          (kdtree/delete
           (kdtree/delete tree [1 3])
           [3 1])
          [2 2] 4))

;; Same operation, but adding a close point.
(println "\n\nFour points with insertion:\n"
         (kdtree/nearest-neighbor
          (kdtree/insert tree [1.5 1.5])
          [2 2] 4))

License

Copyright (C) 2009-2012 Brendan Ribera. All rights reserved.

Distributed under the MIT License; see the file LICENSE at the root of this distribution.