From deleeuw@stat.ucla.edu  Fri Nov 29 06:18:03 2002
From: deleeuw@stat.ucla.edu (Jan de Leeuw)
Date: Fri Nov 29 06:18:03 2002
Subject: [Rd] BLAS/Lapack for OS X
Message-ID: <E708569A-0359-11D7-98F9-000393860F3C@stat.ucla.edu>

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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[Rd] BLAS/Lapack for OS X
Jan de Leeuw