From 136f763a6c64e5e327b2a19d8d76ae471dd4b325 Mon Sep 17 00:00:00 2001 From: Matthew Butterick Date: Tue, 3 Feb 2015 23:46:22 -0800 Subject: [PATCH] start ocm-typed --- quad/ocm-typed.rkt | 35 +++++++++++++++++++++++++++++++++++ 1 file changed, 35 insertions(+) create mode 100644 quad/ocm-typed.rkt diff --git a/quad/ocm-typed.rkt b/quad/ocm-typed.rkt new file mode 100644 index 00000000..9d180312 --- /dev/null +++ b/quad/ocm-typed.rkt @@ -0,0 +1,35 @@ +#lang typed/racket/base +(require (for-syntax racket/base racket/syntax)) +(require racket/list sugar/debug rackunit racket/function racket/vector sugar/cache "logger-typed.rkt") +(define-logger ocm) + +#| +Totally monotone matrix searching algorithms. + +The offline algorithm in ConcaveMinima is from Agarwal, Klawe, Moran, +Shor, and Wilbur, Geometric applications of a matrix searching algorithm, +Algorithmica 2, pp. 195-208 (1987). + +The online algorithm in OnlineConcaveMinima is from Galil and Park, +A linear time algorithm for concave one-dimensional dynamic programming, +manuscript, 1989, which simplifies earlier work on the same problem +by Wilbur (J. Algorithms 1988) and Eppstein (J. Algorithms 1990). + +D. Eppstein, March 2002, significantly revised August 2005 + +|# + +;(provide smawky? make-ocm reduce reduce2 (prefix-out ocm- (combine-out min-value min-index))) + +(define (select-elements xs is) + (map (curry list-ref xs) is)) + +(define (odd-elements xs) + (select-elements xs (range 1 (length xs) 2))) + +(define (vector-odd-elements xs) + (for/vector ([i (in-range (vector-length xs))] #:when (odd? i)) + (vector-ref xs i))) + +(define (even-elements xs) + (select-elements xs (range 0 (length xs) 2)))