[Numpy-discussion] LAPACK/BLAS for Fedora core 4 i386 ?

Chris Barker Chris.Barker at noaa.gov
Thu Jul 28 08:31:27 CDT 2005

Jochen Küpper wrote:
>>Does anyone have a suggestion for how to add the addional lapack
>>stuff I need, while still using atlas stuff where possible?
> See the ATLAS installation manual.

Thanks for the tip.

Do you mean this? :

******** GETTING A FULL LAPACK LIB **************************
ATLAS does not provide a full lapack library.  However, there is a 
simple way
to get ATLAS to provide its faster LAPACK routines to a full LAPACK library.
ATLAS's internal routines are distinct from LAPACK's, so it is safe to 
ATLAS's LAPACK routines directly into a netlib-style LAPACK library.
First, obtain the LAPACK src from netlib and build the LAPACK library as
normal.  Then, in this directory (where you should have a liblapack.a),
issue the following commands:
   mkdir tmp
   cd tmp
   ar x ../liblapack.a
   cp <your LAPACK path & lib> ../liblapack.a
   ar r ../liblapack.a *.o
   cd ..
   rm -rf tmp

Just linking in ATLAS's liblapack.a first will not get you the best LAPACK
performance, mainly because LAPACK's untuned ILAENV will be used instead
of ATLAS's tuned one.

If so, I did that (see a later post to this list). However, I found that 
I got about the same performance improvement doing this as I had gotten 
compiling against just the atlas BLAS and lapack_lite. It makes me 
wonder if I'm really getting the benefit of atlas lapack.

I don't' have hard-core performance needs at the moment, so I'm done, 
but I'm still surprised I couldn't find a ready-to-go atlas rpm for 
Fedora Core 4. It actually makes me miss Gentoo.


Christopher Barker, Ph.D.
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Chris.Barker at noaa.gov

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