[SciPy-user] ATLAS and gcc v4.0.2

Favre-Nicolin Vincent vincefn at users.sourceforge.net
Tue Feb 28 02:58:47 CST 2006


> ATLAS has detected that you are running on an x86
> architecture
> (eg., Athlon, P4, PIII, etc), but do not have a pre-2.96
> gcc installed.
> Using gcc 3/2.96 will result in a performance loss of
> over a gcc previous to 2.96.  If your install goes
> slightly wrong, performance
> drops of 50% are more normal with these compilers.  Full
> details of this
> problem can be found at:
>     http://www.cs.utk.edu/~rwhaley/ATLAS/gcc30.html

   If you actually click on the link you can read that "all of these problems 
appear to be fixed in gcc 3.1". So the message appears to be outdated, and 
should not apply to gcc 4.0.2. Do not be stopped by a mere warning !

   But I am not an atlas expert, just one of many people who is annoyed by the 
incomplete blas/lapack libraries, so that one cannot invert a matrix in scipy 
without compiling atlas, which can be a major pain.
   Of course I have not yet switched to the new scipy, so maybe things are 
better now. Or packagers have finally decided to ban incomplete blas/lapack 
libraries and therefore build a better world where the sky is blue and 
matrices invert.

Vincent Favre-Nicolin
Université Joseph Fourier
ObjCryst & Fox : http://objcryst.sourceforge.net

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