[SciPy-user] making an existing scipy installation use atlas?libraries

Lev Givon lev@columbia....
Mon Oct 8 12:20:15 CDT 2007


Received from Eike Welk on Mon, Oct 08, 2007 at 01:07:25PM EDT:
> On Monday 08 October 2007 17:00, Lev Givon wrote:
> > Received from Robert Kern on Sun, Oct 07, 2007 at 03:29:42PM EDT:
> > > Lev Givon wrote:
> > > > The scipy installation instructions for Linux relating to atlas
> > > > (http://tinyurl.com/2kuwcy) appear to imply that one can force
> > > > an existing scipy installation that was built against netlib
> > > > blas and lapack to take advantage of subsequently installed
> > > > atlas libraries by directing the library loader to point to the
> > > > atlas-provided libblas.so and liblapack.so libraries rather
> > > > than their netlib equivalents. Does this approach provide
> > > > inferior performance compared to building numpy/scipy directly
> > > > against atlas (i.e., such that the atlas objects are built into
> > > > the cblas/clapack modules)?
> > >
> > > ATLAS has a few other libraries that are needed besides its
> > > libblas.so and liblapack.so.  You would essentially have to
> > > relink the extension modules, not just change LD_LIBRARY_PATH.
> >
> > True, but isn't it sufficient that those libraries (e.g.,
> > libatlas.so) are already linked to by the atlas-provided libblas.so
> > and liblapack.so libraries? After all, aren't the BLAS/LAPACK
> > functions the only public interfaces to the atlas stuff that are
> > accessed by programs/libraries that use them? Or do some of the
> > extension modules you mentioned actually access other
> > atlas-specific routines when built against atlas?
>  
> You could ask David Cournapeau. He has created an Atlas package for 
> Suse Linux, that works the way you propose: Select Atlas by putting 
> the directory, where it is stored, into LD_LIBRARY_PATH.
> 
> See 'ashigabou repository' at:
> http://www.scipy.org/Installing_SciPy/Linux

That snippet on the above page is actually what prompted my curiosity
regarding this whole topic :-)

The Fedora folks, incidentally, have also concocted an rpm package
that facilitates building and installing atlas in a manner germane to
the above approach to making an existing dynamically linked
blas/lapack-dependent program/library use atlas.

							L.G.


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