[HEADSUP] Atlas changed libraries

[Richard W.M. Jones]

On Sun, Sep 22, 2013 at 10:05:12PM +0300, Susi Lehtola wrote:
> On Sat, 21 Sep 2013 19:22:11 -0600
> Jerry James <loganjerry at gmail.com> wrote:
> 
> > On Sat, Sep 21, 2013 at 2:13 PM, Frantisek Kluknavsky
> > <fkluknav at redhat.com> wrote:
> > > Hi,
> > >
> > > Atlas in rawhide is rebased to 3.10.1. It now builds monolithic
> > > shared libraries libsatlas.so and libtatlas.so (serial and
> > > threaded, otherwise identical) which include former lapack, blas
> > > and atlas libraries. Dependent packages need to link -lsatlas or
> > > -ltatlas instead of -latlas -lcblas -llapack.
> > >
> > > I am sorry, have a nice day and happy rebuilding.
> > >
> > > Frantisek Kluknavsky
> > 
> > Given this change, is there any point in keeping the libraries in
> > %{_libdir}/atlas instead of putting them directly into %{_libdir}?
> 
> I don't think so. The separate directory was necessary before, since
> ATLAS shipped its own modified copy of lapack with an identical library
> name (liblapack) as lapack.
> 
> However, ATLAS still has different flavors for different CPUs (e.g.
> 3dnow, sse, sse2, sse3 etc). I'm not sure if this can be easily handled
> with alternatives.

Grrrr.

Please don't [to ATLAS upstream, not Susi] do this.  It breaks all
sorts of scenarios, especially virtual machine migration or simply
moving hard disks from one physical machine to another.

Arrange your code so it chooses the best available routines when the
program starts up, and compile every feasible alternative into the
binary.  Or use kernel vdso/user-helper functions when that is
applicable.

Rich.

-- 
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