[racket] generator performance (again)

On Sun, Oct 7, 2012 at 11:34 AM, Patrick Useldinger
<uselpa.list at gmail.com> wrote:
> Hi,
>
> following up on my earlier thread (sep 16th) on the same subject, I tried to
> compare some solutions generating fibonacci series in a lazy way: via a
> closure, via generators and using delay/force.

Hmmm!  Looking at it now...  Wait: your definition of fibo-gen2 is not
exactly equivalent to the others in terms of work when verbose is off.

Change your definition to:

;;;;;;
(define (run-fibo-gen2 count verbose)
  (printf "fibo-gen2 : ")
  (for ( [i (in-range count)] )
    (define next-val (fibo-gen))
    (when verbose (printf "~a " next-val)))
  (when verbose (printf "\n")))
;;;;;;


Otherwise, the third version doesn't even touch the sequence unless
verbosity is on.  How do the results compare once you make this
change?