[Rd] BLAS/Lapack for OS X

ripley@stats.ox.ac.uk ripley@stats.ox.ac.uk
Fri Nov 29 09:04:02 2002

We do not use optimized LAPACKs because too many of them contain
errors (one of which is in the current LAPACK sources and for which we
use a modified souce with a modified name).  That's stated in
the distribution somewhere.

There's nothing to allow you to build with an optimized LAPACK.  The
current code does work with some blases that contain lapack routines, e.g.
sunperf.  I have hacked the code to use sunperf and on real problems the
gain is negligible.

If `which do not work in combination with the BLAS from vecLib' is true,
then your library is not providing a proper BLAS interface, but I would be
interested to know what `does not work' means (it is the dreaded phrase of
technical support staff).

I have plans to have BLAS support in a shared library (as on Windows).
There are some potential problems (e.g. ATLAS is built without PIC flags)
and I do intend to get back to this for 1.7.x. The main potential problem
will be the non-standard behaviour of MacOS X, I believe.

On Thu, 28 Nov 2002, Jan de Leeuw wrote:

> OS X 10.2 and higher comes standard with highly optimized versions
> of BLAS and Lapack in /Systems/Library/Frameworks/vecLib.framework.
> It seems that even for double precision they do much better. See
> http://sthmac.magnet.fsu.edu/benchmarks/
> I am not sure how these numbers would look on G3 Macs, but
> obviously for double precision there is not much reliance on Altivec.
> So I tried to configure R-devel with --with-blas="-framework vecLib",
> which seems to work well since --with-blas is used literally as a
> linker flag
> But later the build gets into trouble because of the
> Lapack sources in the R distribution, which define the same
> (non-optimized) functions as the (optimized) functions in vecLib.
> Thus double definitions, different sources, the linker uses the
> R-versions
> which come first and  which do not work in combination with the BLAS
> from vecLib.
> In this case we may also need  a flag --with-lapack="-framework vecLib",
> which implies it should not use the Lapack files in R to build
> lapack.so. Since Mac OS X 10.2 and higher always comes with
> both Lapack and BLAS this could be the default in configure for
> those systems.
> ===
> Jan de Leeuw; Professor and Chair, UCLA Department of Statistics;
> Editor: Journal of Multivariate Analysis, Journal of Statistical
> Software
> US mail: 9432 Boelter Hall, Box 951554, Los Angeles, CA 90095-1554
> phone (310)-825-9550;  fax (310)-206-5658;  email: deleeuw@stat.ucla.edu
> homepage: http://gifi.stat.ucla.edu
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Brian D. Ripley,                  ripley@stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford,             Tel:  +44 1865 272861 (self)
1 South Parks Road,                     +44 1865 272860 (secr)
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