Re: multi-threaded octave?

[Paul Kienzle]

Shahbaz Chaudhary wrote:

> Hi, I just installed Octave and it works great.  But as I was running a
> particularly long computation, I noticed that it was only using one of
> my cpus (my computer has two).  Apparently it is single threaded...is
> there a multi-threaded version of the program?
No.

> Actually I installed octave (and every thing it depended on) using
> redhat RPMs (for my RH 7.3) system.  Later I found out about
> ATLAS...while I was installing that it asked my about multiple threads.
> Once I had configured and installed atlas, I ran my octave session
> again, but didn't see any difference...I'm not sure if that is because
> my pre-existing octave didn't even pickup the newly installed atlas.
If you are not seeing any performance gain on matrix multiplication for 
larger matrices
(e.g., x=rand(100); tic; y=x*x; toc) then you aren't linking against 
atlas.  You may need
to reconfigure and recompile octave from sources.

> Any way, if there is something I can do to improve performance
> (especially since one of my cpus is going to waste), I'll appreciate it.
Serial code will be slow.  Try to get rid of for loops whereever they 
occur.  Make sure you
preallocate matrices rather than extending them.  Once you have your 
algorithm developed,
convert the remaining for loops into C++.

> BTW, if I run octave on Apple's g4...will their vector technology
> significantly speed up octave?  Thanks.
If you have vendor blas which can make use of it then it may.  Altas is 
competitive with
vendor blas in a lot of cases, so you may see no gain.

Paul Kienzle
address@hidden




-------------------------------------------------------------
Octave is freely available under the terms of the GNU GPL.

Octave's home on the web:  http://www.octave.org
How to fund new projects:  http://www.octave.org/funding.html
Subscription information:  http://www.octave.org/archive.html
-------------------------------------------------------------