Hi all, I've implemented the 'pfannkuchen' algorithm for the fannkuch-redux benchmark on shootout.alioth.debian.org, since this is the only remaining benchmark without a Racket attempt. It seemed like a fun newbie project.
I'd appreciate any optimization hints or general comments and criticism of my coding. The full code is at https://github.com/cbowdon/Fannkuch-Redux. In terms of optimization, the worst offender is the following function: ;; perform flipping on a single permutation, return number of flips (define (fannkuch input) ;; perform a single rearrangement (define (single-flip source result count) (if [= count 0] result (single-flip (cdr source) (cons (car source) result) (sub1 count)))) ;; flip until (car lst) is 1 (define (multi-flip lst number-of-flips) (let ([l (car lst)]) (if [= l 1] number-of-flips (multi-flip (single-flip lst (drop lst l) l) (add1 number-of-flips))))) (multi-flip input 0)) Any advice? Profiling suggested that 70% of time is spent in this function. Best regards, Chris P.S. Kindly note that this is a question about some code, not a meta-discussion on computer language benchmarks etc.
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