Bug#595326: libatlas3gf-base: Suggested fix to provide multithreaded Atlas libraries

[Dirk Eddelbuettel]

Package: libatlas3gf-base
Version: 3.8.3-25
Severity: important
Tags: patch

Hi Sylvestre,

I finally managed to get mulitthreaded Atlas working. I started from
Atlas 3.9.25, the newest and shiniest, and then tried to see what I
needed from our patch set to get shared libraries the way 'we' use
them on Debian -- so that I get the pluggability I use in the paper I
sent you a draft of. 

The key is in 03_full_blas_lapack.diff

+# Build full netlib blas/lapack libraries:
+atlas/libblas.a: libatlas.a libf77blas.a libcblas.a
+	mkdir tmp
+	(cd tmp && ar x ../libatlas.a);
+	(cd tmp && ar x ../libf77blas.a);
+	(cd tmp && ar x ../libcblas.a);
+	ar r $@ tmp/*.o
+	rm -rf tmp

We extract the fully built object files from libf77blas.a and
libcblas.a.  If instead you use

atlas/libblas.a: libatlas.a libf77blas.a libcblas.a
	mkdir tmp
	(cd tmp && ar x ../libatlas.a);
	(cd tmp && ar x ../libptf77blas.a);
	(cd tmp && ar x ../libptcblas.a);
	ar r $@ tmp/*.o
	rm -rf tmp

ie you employ the _parallel threaded_ versions that have also been
built then everything is good. 

I have a basic (local) libatlas39 package in use here, and I can show
you results from an update of the paper that clearly show the manifold
increase in speed.

Now, maybe we need single-threaded and multi-threaded versions.  Or
maybe you can switch based on a user variable?  I leave that in your
capable maintainer hands. 

Me, I am just happy that I have an Atlas version that is closing the
gap to Goto BLAS and the Intel MKL BLAS. 

Cheers, Dirk



-- System Information:
Debian Release: squeeze/sid
  APT prefers lucid-updates
  APT policy: (500, 'lucid-updates'), (500, 'lucid-security'), (500, 'lucid')
Architecture: amd64 (x86_64)

Kernel: Linux 2.6.32-23-generic (SMP w/8 CPU cores)
Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash

Versions of packages libatlas3gf-base depends on:
ii  libc6                  2.11.1-0ubuntu7.2 Embedded GNU C Library: Shared lib
ii  libgcc1                1:4.4.3-4ubuntu5  GCC support library
ii  libgfortran3           4.4.3-4ubuntu5    Runtime library for GNU Fortran ap

libatlas3gf-base recommends no packages.

Versions of packages libatlas3gf-base suggests:
ii  libblas3gf                    1.2-7      Basic Linear Algebra Reference imp
ii  liblapack3gf                  3.2.2-1    library of linear algebra routines

-- no debconf information