Göran Broström gb at stat.umu.se
Mon Aug 29 16:41:11 CEST 2005

On Mon, Aug 29, 2005 at 02:43:28PM +0100, Prof Brian Ripley wrote:
> 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.

Well, the ATLAS sources contain 'xerbla.f'. So what does 'does not provide 
it' mean? Not included in the build process?


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