Re: About octave performance...

[Jaroslav Hajek]

On Wed, Jul 30, 2008 at 10:52 AM, David Bateman
<address@hidden> wrote:
> Francesco Riganti wrote:
>> Dear All,
>> first of all, a very big "tank you" for this wonderful project. I have a
>> little question: in the next feature of octave, it will be an
>> improvement versus matlab performance?
>> Actually, i think this is the most immediate problem to solve. Infact,
>> despite the use of vectorization, matlab is more fast then octave. In my
>> university, I would like to build a cluster system for octave using
>> instead of matlab sofware. However, the not yet good performance of
>> octave versus matlab, not encourage the cluster project. Can you tell me
>> something about it?
>> Best Regards
>>
>> Francesco Riganti Fulginei
>> Department of Applied Electronics
>> Roma Tre University
>> Rome
>>
>> _______________________________________________
>> Help-octave mailing list
>> address@hidden
>> https://www.cae.wisc.edu/mailman/listinfo/help-octave
>>
>>
> Take a look at the thread
>
> https://www.cae.wisc.edu/pipermail/octave-maintainers/2008-April/006984.html
>
> in short FreeMat has started implementing LLVM JIT in their development
> tree and I imagine we'll copy their code once they make some progress. I
> therefore expect this to be a target for the 3.4.x (or will that release
> be 4.0) of Octave sometime in about a years time.
>

Interesting. But you do expect that the "copy" operation will actually
be quite complex, don't you? Or are FreeMat internals that close to
Octave's?

In any case, I'm still not much assured that the Matlab's way is the good way.
As John once noted, the key problem in JIT is about type inference,
not the code compilation itself. How do you know that the JIT compiler
will be smart enough? If you know (or assume) that a variable is of
certain type, why not let the compiler know? Perhaps some kind of type
declaration or "type assertion" directives would enable much better
JIT optimization, without black magic like "if you use complex value
here, the code will run 2x slower" etc.

> Regards
> David
>
> --
> David Bateman                                address@hidden
> Motorola Labs - Paris                        +33 1 69 35 48 04 (Ph)
> Parc Les Algorithmes, Commune de St Aubin    +33 6 72 01 06 33 (Mob)
> 91193 Gif-Sur-Yvette FRANCE                  +33 1 69 35 77 01 (Fax)
>
> The information contained in this communication has been classified as:
>
> [x] General Business Information
> [ ] Motorola Internal Use Only
> [ ] Motorola Confidential Proprietary
>
> _______________________________________________
> Help-octave mailing list
> address@hidden
> https://www.cae.wisc.edu/mailman/listinfo/help-octave
>



-- 
RNDr. Jaroslav Hajek
computing expert
Aeronautical Research and Test Institute (VZLU)
Prague, Czech Republic
url: www.highegg.matfyz.cz