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[Lapack] A few routines missing from BLAS reference implementation?


Hello Huub,

the LAPACKers can certainly discuss this problem next time there is a 
meeting. Just to answer quickly, the BLAS directory in LAPACK is not 
advertised nor meant to be the whole BLAS. It covers only the BLAS 
routines needed by LAPACK. This was a choice made at a point in time. The 
compromise is still up to date:

- either you only provide the BLAS you need and then people complains that
   you are not providing the full BLAS implementation,

- or you provide the full BLAS for sake of completeness, and then you have
   as much people complaining for dead codes.

The initial goal of the BLAS in LAPACK was to satisfied LAPACK needs.

Now it is true that the BLAS provided by LAPACK is almost complete and 
whether or not to include the whole BLAS is argueed regularly.

I am sure the LAPACKers can discuss this item once more time :). We let 
you know the answer of the group.

Thanks for rising the issue,

Just another quick point: I hope you are aware of the sacrifice in term of 
performance you are making by using reference BLAS for improving 
portability, ease of installation, etc. This is really not a trivial 
choice you are making. Ideally, you should link with any optimized BLAS 
implementaion beneath. I do not know exactly what is the situation with 
the Goto BLAS, ATLAS BLAS, ESSL, ACML, MKL BLAS, but that would be much 
nicer if there is some kind of way for you to link against them instead of 
our not optimized reference implementation.
Just raising the issue, not providing solution though.

Best,
Julien




On Sat, 22 Jul 2006, Van Dam, HJJ \(Huub\) wrote:

Hi,

I have recently downloaded and installed LAPACK to be used in the 
context of a Python installation with the NumPy and SciPy extensions. 
Due to various problems with the installation of Python and its 
extensions I decided to compromise on performance and compile everything 
from source so that I would have the best control over how things were 
compiled to avoid getting bitten by issues such as 32-bit vs. 64-bit 
integers, no-underscores through to double underscores on subroutine 
names, etc. So I compiled and used the BLAS reference implementation 
that is supplied with LAPACK. However when I came to link SciPy I 
discovered there were a few BLAS routines missing, they are:

- csrot,
- drotm,
- drotmg,
- dsdot,
- sdsdot,
- srotm,
- srotmg,
- zdrot

These are available from the BLAS library provided by netlib 
http://www.netlib.org/blas . Could you add these to the LAPACK BLAS 
tar-ball, please? The Python setup I mentioned is rather popular where I 
work therefore I am sure we'll hit this problem again, so if you could 
fix it it would surely help.

Thank you,

   Huub


==========================================================
Huub van Dam                  email: h.j.j.vandam@Domain.Removed
CCLRC Daresbury Laboratory    phone: +44-1925-603933
Daresbury, Warrington           fax: +44-1925-603634
Cheshire, UK
WA4 4AD
==========================================================

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