Re: [oliver: Re: [Caml-list] Strings as arrays or lists...]

[Issac Trotts <ijtrotts@ucdavis.edu>]

Alain.Frisch@ens.fr wrote:

>On Mon, 3 Mar 2003, Issac Trotts wrote:
>
>  
>
>>Char arrays take up four times as much space as strings, but there is a
>>tradeoff
>>of space versus time.  The statement
>>
>>  let a = Array.make 2000000 ' ';;
>>
>>takes no noticable time, but
>>
>>  let s = String.make 2000000 ' ';;
>>
>>takes about 7 seconds to run on my computer.
>>    
>>
>
>
>Oh really ?  I'm interested in your benchmark methodology. Hint: it may
>be the case that the pretty-printing of s in the toplevel is slower that
>the pretty-printing of a, but this is not relevant, is it ?
>
>
>As for me, I get:
>
>glouglou ~/tmp $ cat a.ml
>let a = Array.make 2000000 ' ';;
>glouglou ~/tmp $ time ocaml a.ml
>ocaml a.ml  0,16s user 0,01s system 101% cpu 0,167 total
>glouglou ~/tmp $ cat s.ml
>let s = String.make 2000000 ' ';;
>glouglou ~/tmp $ time ocaml s.ml
>ocaml s.ml  0,04s user 0,02s system 102% cpu 0,058 total
>glouglou ~/tmp $ cat x.ml
>glouglou ~/tmp $ time ocaml x.ml
>ocaml x.ml  0,03s user 0,01s system 108% cpu 0,037 total
>
>(x.ml is an empty file, to evaluate ocaml toplevel startup time)
>Which seems to indicate that String.make is unsurpisingly a lot faster
>than Array.make.
>
>-- Alain
>  
>
You're right.  Thanks for catching my error.  

Issac





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