[Rd] BLAS and ATLAS

[Prof Brian Ripley]

On Mon, 29 Aug 2005, Göran Broström wrote:

> On Mon, Aug 29, 2005 at 11:48:23AM +0100, Prof Brian Ripley wrote:
>> On Mon, 29 Aug 2005, Göran Broström wrote:
>
>>> LAPACK/BLAS routines call xerbla "if an input parameter has an
>>> invalid value" (exact quote from  XERBLA at Netlib). Other types of errors
>>> are not printed (by xerbla), but it is up to the user to check the return
>>> value of the argument 'INFO'. See
>>> http://www.netlib.org/lapack/lug/node119.html.
>>
>> Maybe, that is not actually true for real-life LAPACK implementations, as
>> I did say.
>>
>>> So we can safely give the more informative, original, error messages,
>>> together with mentioning LAPACK and eventually BLAS, whatever you prefer.
>>> This would "make clear what these refer to". Given that other BLAS/LAPACK
>>> routines than xerbla aren't changed in R, of course.
>>
>> Irrelevant as R is often compiled against other ones implementations.
>
> That confuses me. My R installation (R-devel of yesterday) is compiled
> against ATLAS BLAS (from Debian-unstable). Why, then, is xerbla from  R
> sources used anyway?

Because it is the only one seen: ATLAS does not provide it.  There is no 
guarantee that ATLAS or libsunperf or vecLib ... only use xerbla in the 
meaning in that page.

-- 
Brian D. Ripley,                  ripley at stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford,             Tel:  +44 1865 272861 (self)
1 South Parks Road,                     +44 1865 272866 (PA)
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