[Scilab-users] Ways to speed up simple things in Scilab ?

[Brian Bouterse]

I don't know much about scilab optimizations, but trying to hand-optimize
auto-generated code almost certainly will result in correctness problems.
It's likely better to make your improvements in the software that is
generating the scilab code. I think the main feature there is to have it
generate a vectorized implementation instead of a procedural one (as you
have now).

-Brian

On Fri, Apr 24, 2015 at 8:34 AM, Stéphane Mottelet <stephane.mottelet at utc.fr
> wrote:

>  Hello,
>
> this is not trivial indexing, in fact some terms are linear combination of
> v's components
>
> M1_v=[v(17)
> v(104)
> v(149)
> -(v(18)+v(63)+v(103))
> -(v(18)+v(63)+v(103))
> v(17)
> ...
> v(104)
> v(149)
> ]
>
> How do you take this into account in your proposed method ? These
> combinations are sums of influxes in a metabolic network, and the code is
> automatically generated.
>
>
> S.
>
>
>
> Le 24/04/2015 13:48, Samuel Gougeon a écrit :
>
> Le 24/04/2015 13:36, Samuel Gougeon a écrit :
>
> Hello Stephane,
>
> You can speed up by a factor larger than 100 just by calling v once (or 3
> times) instead of ~1000, as shown by this test:
>
>
> Actually, to be more accurate, the right comparative test is the following:
>
> function test2()
>     v = rand(172,1);
>     p = grand(1,839,"unf",1,173)
>     // Part 1: 1 call to v()
>     tic()
>     for i=1:1000
>         m1_v = v(p)
>     end
>     disp(toc())
>
>     // Part 2 : 839 calls to v()
>     deff("test3()", "for i=1:1000, M1_v = [ "+strcat("v("+string(p)+") ")+"], end")
>     tic()
>     test3()
>     disp(toc())endfunction
>
>
> In this version, the compilation time used by execstr() is no longer taken
> into account.
>
> The results are still explicit:
> -->test2()
>
>     0.016
>
>     0.78
>
> So, a speed-up by ~x 50
>
> Samuel
>
>
>
> _______________________________________________
> users mailing listusers at lists.scilab.orghttp://lists.scilab.org/mailman/listinfo/users
>
>
>
> _______________________________________________
> users mailing list
> users at lists.scilab.org
> http://lists.scilab.org/mailman/listinfo/users
>
>


-- 
Brian Bouterse
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.scilab.org/pipermail/users/attachments/20150424/56bacfb1/attachment.htm>