Discussion of Scientific Python

Pearu Peterson | 9 Jan 2003 09:42

Re: Question about ATLAS usage in SciPy


On Wed, 8 Jan 2003, Fernando Perez wrote:

> I have a question concerning the use of atlas static libraries. I built 
> atlas on my system as per their standard instructions, resulting in a set 
> of static libraries (this is on a RedHat 8.0 machine). I put these in 
> /usr/local/lib, and ran ldconfig.
> 
> When I start the scipy build, it correctly seems to detect atlas:
> 
> root[scipy]# python setup.py build
> atlas_info:
>   FOUND:
>     libraries = ['lapack', 'f77blas', 'cblas', 'atlas']
>     library_dirs = ['/usr/local/lib']
>     include_dirs = ['/usr/local/include']
> 
> /usr/bin/python 
> /usr/local/installers/python/scipy/scipy/linalg/setup_atlas_version.py 
> build_ext --inplace --force
> /usr/bin/python -c "import atlas_version"
> ATLAS version 3.4.1
> 
> 
> However, my system _also_ has dynamical versions of blas and lapack 
> provided by redhat in /usr/lib:
> 
> root[lib]# ls /usr/lib/*blas*so*
> /usr/lib/libblas.so <at>     /usr/lib/libblas.so.3.0 <at>     
> /usr/lib/libgslcblas.so.0 <at>

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Fernando Perez | 9 Jan 2003 19:16

Re: Question about ATLAS usage in SciPy

On Thu, 9 Jan 2003, Pearu Peterson wrote:

> > My question is: is the scipy build process smart enough to link the static 
> > atlas libraries, or will the default behavior of the compiler (dynamic 
> > linking) slip through? After going through the work of building/installing 
> > atlas, I don't want to end up with scipy using the stock unoptimized 
> > blas/lapack for everything.
[snip]

> 
> However, since in your case the command 
>   /usr/bin/python -c "import atlas_version"
> shows the correct ATLAS version (right?) then I am pretty sure that
> also scipy is linked against static lapack library from /usr/local/lib.
> 
> But to be absolutely sure, apply ldd to one of the extension modules that
> is supposed to use lapack library. The output should not contain any
> references to /usr/lib/liblapack.so*.

Thank you. Indeed, running ldd on all the extension modules in linalg 
shows no references to any of the blas/lapack dynamic libraries. All seems 
well then.  I just wanted to be sure and to understand how the process 
works.

Best regards,

Fernando.