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

[Sylvestre Ledru]

Le jeudi 03 septembre 2009 à 16:25 +0900, David Cournapeau a écrit :
> (resending to the list)
> 
> On Thu, Sep 3, 2009 at 3:49 PM, Sylvestre Ledru<sylvestre at debian.org> wrote:
> 
> > I am doing it. I am disabling SEE extensions in the base package.
> 
> You mean by forcing the ISA with -A/-V options ? Unfortunately, that's
> not enough. For example, if I configure atlas as follows:
> 
> ../configure -V -1 -A 9 -b 32 -t 0
> 
> on a recent core2duo, the generated library still contains SSE
> instructions (and the test binaries crash on qemu with SSE disabled).
> The first patch in the git repository + the arch defaults in
> debian/ARCHS take care of this issue (for x86).
> 
> To check my patch was working, I used a perl script found somewhere to
> check whether a given binary contains any SIMD instruction set (by
> disassembling and counting each SIMD set).
OK, I haven't been that deep. 
Well done. I am sure that Atlas people would be interested by such
patch.

> > If you saw my efforts, why didn't you come to help ?
> 
> I wanted to fix the above problem first, and at that point, doing my
> own rule file was easier than trying to understand someone else's. Now
> that I know it works, I would like to see those patches included on
> top of your effort.
OK. Anyway, your approach is very similar to mine. You would not have to many problems to understand it.

> > It is done at build time. I am just saying to the atlas configure that I want a build specific to this arch.
> 
> But what happens if you install both sse3 and the core i7 packages ?
For now, they are stored in specific directory. You explicitly need to specific one or this other when you want to use it.
I am going to provide a way to change that but I haven't check what
would be the best solution here.

Sylvestre