[Pkg-scicomp-devel] Fixing atlas on debian/Ubuntu

[Sylvestre Ledru]

Le jeudi 03 septembre 2009 à 15:38 +0900, David Cournapeau a écrit :
> On Thu, Sep 3, 2009 at 3:31 PM, Sylvestre Ledru<sylvestre at debian.org> wrote:
> > Hello,
> >
> > Le jeudi 03 septembre 2009 à 15:27 +0900, David Cournapeau a écrit :
> >> Hi,
> >>
> >> I am a Numpy/Scipy developer, and we recently got a lot of trouble
> >> from users of recent ubuntu and debian, because the atlas libraries
> >> are broken (the SSE2 version give bogus results whenever complex
> >> number are involved in 32 bits).
> >>
> >> Since the current debian package is near-impossible to decipher, I
> >> started from scratch a package so that we could point numpy/scipy
> >> users to a an ubuntu build on PPA. Now, I would like this effort to be
> >> useful for "upstream" debian packagers. The packaging was done under
> >> git, and the code available there:
> >>
> >> http://github.com/cournape/atlas-debian/tree/master
> >
> > Well, bad luck, you have been duplicating a on-going work ... :/
> > See: http://svn.debian.org/viewsvn/pkg-scicomp/atlas/trunk/
> 
> well, not exactly :)  I saw your effort, but I spent most of my time
> making sure to produce a binary without a single SSE instruction if
> requested on a modern CPU, which you did not implement I believe.
I am doing it. I am disabling SEE extensions in the base package.
If you saw my efforts, why didn't you come to help ?
Managing atlas is a work big enough for two maintainers...

> While looking at your work, I was wondering how you could use
> different binaries for modern CPU (i.e. the HWCAP flag mechanism). I
> could not find useful information on what exactly can it be used for -
> your work seems to imply that it can make the difference between
> recent i7 Intel CPU and Core 2 Duo, but I could not find any
> confirmation anywhere.
It is done at build time. I am just saying to the atlas configure that I want a build specific to this arch.

Sylvestre