memoize

  1. memoize
    1. Description
    2. Author
    3. Requirements
    4. Documentation
      1. Examples
    5. Changelog
    6. License

Description

Memoize is a CHICKEN Scheme egg that provides procedure memoization.

Author

Arthur Maciel

Requirements

Requires srfi-69 egg.

Documentation

[procedure] (memoize PROC #!optional LIMIT)

Memoizes procedure PROC. LIMIT is an integer optionally set to avoid excessive memory usage.

Examples

(use memoize)

;; Factorial - Tail-call optimization version
(define (fact x)
  (let loop ((x x) (acc 1))
    (if (= x 0)
	acc
	(loop (- x 1) (* x acc)))))

(time (fact 10000000))
; => 3.011s CPU time, 0.071s GC time (major), 16 mutations, 104/27101 GCs (major/minor)


(define memo-fact (memoize fact))

;; First call
(time (memo-fact 10000000))
; => 3.199s CPU time, 0.243s GC time (major), 22 mutations, 223/26982 GCs (major/minor)

;; Second call on...
(time (memo-fact 10000000))
; => 0s CPU time, 10 mutations

Changelog

License

 Copyright (c) 2013, Arthur Maciel
 All rights reserved.
 
 Redistribution and use in source and binary forms, with or without
 modification, are permitted provided that the following conditions are
 met:
 
 Redistributions of source code must retain the above copyright
 notice, this list of conditions and the following disclaimer.
 
 Redistributions in binary form must reproduce the above copyright
 notice, this list of conditions and the following disclaimer in the
 documentation and/or other materials provided with the distribution.
 
 Neither the name of the author nor the names of its contributors may
 be used to endorse or promote products derived from this software
 without specific prior written permission.
 
 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
 COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
 INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
 STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
 OF THE POSSIBILITY OF SUCH DAMAGE.