How to switch between the various BLAS/LAPACK implementations
=============================================================

BLAS:
$ sudo update-alternatives --config libblas.so.3

LAPACK:
$ sudo update-alternatives --config liblapack.so.3

Note that the LAPACK alternative should not point to ATLAS when then BLAS
alternative points to OpenBLAS, otherwise you will get crashes (see #576972).

More information is available at:

 http://wiki.debian.org/DebianScience/LinearAlgebraLibraries


Building an optimized OpenBLAS packages on your architecture
============================================================

Since version openblas 0.1alpha1-5, libopenblas-base provides a multiple
architecture library. All kernels are included in the library and the one
matching your architecture is selected at run time.

An alternative is to create a custom OpenBLAS package, optimized for your
specific machine, as explained below.

Install the build dependencies:

$ sudo aptitude build-dep openblas
$ sudo aptitude install devscripts

Get the sources of the package:

$ apt-get source openblas

Compile the package:

$ cd openblas-<VERSION>
$ fakeroot debian/rules custom

It should produce a package that you can install with:

$ sudo dpkg -i ../libopenblas-base_<DEBVERSION>.deb

 -- Sylvestre Ledru <sylvestre@debian.org>  Tue, 31 May 2011 13:56:22 +0200
 -- Sébastien Villemot <sebastien@debian.org>, Thu, 13 Dec 2012 13:09:19 +0100
