Blas vs atlas + openblas

[ivo welch]

hi silvestre:  you know this stuff way better than I do.  however, as
an amateur observation, even the basic precompiled atlas, which is
presumably limited, is still "only" 3 times faster than the standard
blas.

my suggestion is not for myself.  I know now that I should immediately
install an alternative like atlas.  instead, my suggestion is for the
sake of the general (student) public.  it would be great if you could
give them something better as a default, be it atlas or something
else.  the current highest priority blas default that ships with
debian/ubunt/mint is badly hobbled, and it impacts the science
performance in such higher-level languages as the binary R
distribution, which ordinary users won't realize.

(and, since I have you on the line, Dirk E posts a nice R 3.0.1 .deb
package on cran.)

best,

/iaw

----
Ivo Welch (ivo.welch at gmail.com)
http://www.ivo-welch.info/
J. Fred Weston Professor of Finance
Anderson School at UCLA, C519
Director, UCLA Anderson Fink Center for Finance and Investments
Free Finance Textbook, http://book.ivo-welch.info/
Editor, Critical Finance Review, http://www.critical-finance-review.org/



On Mon, Jun 24, 2013 at 1:47 PM, Sylvestre Ledru <sylvestre at debian.org> wrote:
> Hello,
>
> On 24/06/2013 19:35, ivo welch wrote:
>>
>> Dear science team.  Would it make sense to give atlas higher priority
>> than blas?
> In a perfect world, we should do that.
>
>
>> It is very solid, and my benchmarks indicate a speedup by a factor 3.
> Sometimes, it is even to a 40 factor.
>
> However, default build of atlas has most of the optimization disabled.
> In Debian, we are targeting old CPU and atlas optimization are done at
> build time and since it relies on the SSE optimization, we cannot enable
> most of the optimization.
>
> The "best" atlas package is the one rebuilt for your specific system
> (see the documentation on README.Debian).
>
> Now, we could discuss doing that with Openblas (AKA Gotoblas).
>
> Cheers,
> Sylvestre
>