Re: ATLAS

[Dmitri A. Sergatskov]

E. Joshua Rigler wrote:
> I'm a little punchy at the moment, and I'll probably kick myself
> tomorrow for asking such dumb questions, but...
>
> 1) Which ones and where should the ATLAS libraries get placed on a
> typical UNIX system once they've been compiled using "make install
> arch=<arch?"? (sorry, that's not really an Octave question, but I figure
> someone on this list should know)

I usually copy all ($ARCH)/lib/*.a files into /usr/local/lib and configure
finds it automatically...

> 2) Are the ATLAS header files necessary to compile Octave with ATLAS
> support? 

I do not think you need any.

> 3) Is there any real advantage to creating shared libraries as opposed
> to the standard static libraries (other than size)?  Will I have any
> problems if I follow the directions provided here:
>
> http://www.octave.org/octave-lists/archive/help-octave.2001/msg00549.html

The major advantage is that you can replace library w/o recompiling octave.
I do not do that.

> 4) Again, not Octave specific, but the results of some comparative
> timings using the ATLAS BLAS, and the default BLAS that comes with
> RedHat 9 seem suspiciously similar.  Does anyone know if they are indeed
> the same?  If so, does anyone have suggestions for something better, or
> is this the best I can do on an Intel P4 architecture?

Did you compile ATLAS yourself? It might be tricky for P4.
Also make sure that configure _does_ find ATLAS libraries. If not, it
will use blas/lapack included with RH9 and you get a binary identical to
the one that came with RH9.

I get almost 50% speedup on _some_ benchmarks but I have an Athlon.

I would recommend getting pre-compiled ATLAS binary at (e.g.):
http://aleron.dl.sourceforge.net/sourceforge/math-atlas/atlas3.4.1_Linux_P4SSE2.tar.gz
(unpack at where you want, copy libs into /usr/local/lib/)


> Thanks for any and all pointers.
>
> -EJR

Regards,

Dmitri.



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