Re: [Caml-list] Optimizing symbolic processing code

[Hugo Ferreira <hmf@inescporto.pt>]

Jon Harrop wrote:
> On Friday 16 January 2009 08:42:52 Hugo Ferreira wrote:
>> Hello,
>>
>> I have implemented a simple Prolog like inference engine
>> to be used in machine learning algorithms (ILP). My first
>> basic test shows that inference is dismally slow (compared
>> to a Prolog compiler).
> 
> Can you quantify that?
> 

Yes. Give or take a second I get the following embarrassingly large
difference:

~/workspace/planner$ time swipl -f prolog.pl -g "win(A, B, C, D, E, F), 
halt."
/home/hugof/workspace/planner/docs/prolog.pl compiled 0.00 sec, 8,560 bytes

real    0m30.278s
user    0m30.222s
sys     0m0.012s

~/workspace/planner$ time ./itest_1.p.native
real	19m12.786s
user	19m6.728s
sys	0m0.196s


>> Consequently I am looking for information on optimizing the code.
> 
> IIRC, the single most productive optimization I made to the Mathematica 
> implementation I wrote in OCaml was to check when recursive rewrites were 
> leaving an expression unaltered and return the original when possible to 
> avoid copying. I don't know if that is relevant here.
> 

Unfortunately not. I am just scanning the Trie repeatedly. I do this
using functional like code using only folds and finds.

> Also IIRC, someone else wrote that they lashed together a quick Prolog 
> implementation in OCaml and were surprised to find it outperforming real 
> Prolog compilers.
> 

Yep. Blue Strom has already pointed out the link. Not quite what I am
looking for.

>> I have found: 
>>
>> http://ocaml.janestreet.com/?q=node/30
>> http://camltastic.blogspot.com/2008/05/optimizing-memory-allocation-and-loo
>> ps.html
>>
>> Does anyone have any other links or articles I may look at?
> 
> The articles on low-level optimization in the OCaml Journal are almost 
> certainly relevant. OCaml for Scientists covers data structure performance in 
> detail. No other sources are as comprehensive with regard to optimization 
> AFAIK.
> 

Was afraid of that.

Thanks.
HF.