[racket] Reversing strings (Jay's article)

Oh, wow. So I was testing this in Geiser repl in emacs:
(2467 4631 4088 3934) Where apparently "slower" one wins

But in DrRacket the result looks plausible:
(8994 1859 1094 865)

Does that mean Geiser shouldn't be trusted?

---
Vlad Kozin <vladilen.kozin at gmail.com>



On Oct 2, 2013, at 1:57 PM, Laurent wrote:

> What values do you get?
> For 4'000 strings (old slow computer), I get:
> (236 148 84 84)
> for slow, medium, fast, really fast, which is consistent with Jay's post.
> 
> Laurent
> 
> 
> On Wed, Oct 2, 2013 at 7:28 PM, Vlad Kozin <vladilen.kozin at gmail.com> wrote:
> Mostly a question to Jay McCarthy but I suppose could be interesting to others. Was going over his Reversing strings article. Somehow I get weird performance. Slowest solution turns out fastest, medium, fast and really fast are only marginally different.
> 
> Could anyone have a look https://github.com/vkz/warm-up
> reverse-string.rkt has the solutions
> test-reverse-string.rkt does the performance check
> Testing it on 40'000 randomly generated strings 1000 chars each.
> 
> While we're at it, why do we garbage-collect thrice here?
> let-values ([(as cpu real gc) (time-apply (λ () exp) empty)])
>     (collect-garbage) (collect-garbage) (collect-garbage)
> 
> Thanks!
> ---
> Vlad Kozin <vladilen.kozin at gmail.com>
> 
> 
> 
> 
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