[Numpy-discussion] Matlab/Numeric/numarray benchmarks

Simon Burton simon at arrowtheory.com
Thu Jan 20 16:17:49 CST 2005


On Thu, 20 Jan 2005 10:24:27 -0500
Jason Rennie <jrennie at csail.mit.edu> wrote:

> All three machines are Debian Sarge with atlas3-sse2 plus all the
> python2.3 packages installed.  I had to include /usr/lib/atlas/sse2 in
> my LD_LIBRARY_PATH.  Anyone have any clue why the Xeon would balk at
> the Numeric matrixmultiply?  Thinking it might be an atlas3-sse2
> issue, I tried atlas-sse:
> 
> Xeon/atlas3-sse/Numeric:	0.0269	10.2	2.44
> Xeon/atlas3-sse/numarray:	2.24	3.41	2.48
> 
> Apparently, there's a bug in the sse2 libraries that numarry is
> tripping...  

Yes, we have the same problem here (Xeons with debian-sarge).
It all works fine on the base atlas but blows on atlas3-sse2.
I also compiled ATLAS 3.6 for sse2 and the same floating point exception happens.

The next thing would be to write a simple c program that trips this exception,
because I'm not convinced it is ATLAS's fault. Doesn't Numeric use the same library calls,
and if so, why doesn't it also trip this exception ?

One other thing I noticed was that atlas3-sse was not noticably faster than atlas3-base.

(And i'm sorry about that bad benchmark code..)

bye for now,

Simon.


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Simon Burton, B.Sc.
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