aphyr / data.interval-tree

Interval Treeset based on finger trees

Interval Treeset

This is a fork of dthume's data.interval-tree, purely to support newer versions of Clojure. It looks like David might be AFK for a bit; hopefully he'll come back and this can go away!

I've changed the project name (for Clojars), but left the namespaces under org.dthume; it should be a drop-in replacement for the original.

About

Interval Treeset built on data.finger-tree.

Largely based on the implementation described in the original paper.

Leiningen

API Docs

codox generated documentation can be found here.

A marginalia generated walkthrough of how to use the library can be found here.

Basic Usage

For a full set of examples, see the walkthrough.

;; just for this documentation
(require '[org.dthume.data.interval-treeset :as it])

Interval Treesets sort their entries by interval. Intervals are simply pairs of values, and you can use vectors to represent them:

[5 10] ; the interval 5 - 10

However you may find it convienient to use the interval function which produces an optimised (but still compatible) interval:

(it/interval 5 10)
;; => [5 10]

This uses clj-tuple to represent the pair.

Treesets can be created using interval-treeset. Because treesets take a number of (optional) configuration options, there is no constructor which takes items to populate the initial treeset with such as clojure.core/vector. Instead treesets are created using interval-treeset and then filled using into:

(def ts (into (it/interval-treeset) [[0 2] [3 5] [6 8]]))
;; => ([0 2] [3 5] [6 8])

If you wish to store something other than raw intervals in the set, then provide an interval lensing function:

(def cts (into (it/interval-treeset :as-interval :span)
               [{:span [6 8] :id 3} {:span [3 5] :id 2} {:span [0 2] :id 1}]))
;; => ({:span [0 2] :id 1} {:span [3 5] :id 2} {:span [6 8] :id 3})

Items will be added at the correct position:

(conj ts [1 4]) ;; Amortized O(log(n))
;; => ([0 2] [1 4] [3 5] [6 8])

(count ts) ;; O(1)
;; => 3

(first ts) ;; Amortized O(1)
;; => [0 2]

(peek ts)  ;; Amortized O(1)
;; => [6 8]

(nth ts 1) ;; O(log(n))
;; => [3 5]

Selections

(require '[org.dthume.data.interval-treeset.selection :as sel)

You should probably not attempt to use or (require ... :refer :all) the selection namespace, since it contains vars which shadow clojure.core.

TODO

• Confirm union correct wrt paper.
• Confirm complexity of intersection / difference
• Customize print-method to print as set rather than seq?

License

Copyright (C) 2014 David Thomas Hume. Distributed under the Eclipse Public License, the same as Clojure.