[Numpy-discussion] RE: [Matrix-SIG] An Experiment in code-cleanup.

Beausoleil, Raymond beausol at exch.hpl.hp.com
Wed Feb 9 13:16:58 CST 2000


From: Konrad Hinsen [mailto:hinsen at cnrs-orleans.fr]

> > (1) The extent of the support for LAPACK. Do we want to stick
> > with LAPACK Lite?
>
> There has been a full LAPACK interface for a long while, of which
> LAPACK Lite is just the subset that is needed for supporting the
> high-level routines in the module LinearAlgebra. I seem to have lost
> the URL to the full version, but it's on my disk, so I can put it
> onto my FTP server if there is a need.

Yes, I'd like to get a copy! You can simply e-mail it to me, if you'd
prefer.

> > (2) The storage format. If we've still got row-ordered matrices
> > under the hood, and we want to use native LAPACK libraries that
> > were compiled using column-major format, then we'll have to be
> > careful to set all of the flags correctly. This isn't going to
> > be a big deal, _unless_ NumPy will support more of LAPACK when a
> > native library is available. Then, of course, there ...
>
> The low-level interface routines don't take care of this. It's the
> high-level Python code (module LinearAlgebra) that sets the
> transposition argument correctly. That looks like a good compromise
> to me.

I'll have to look at this more carefully. Due to my relative lack of Python
experience, I hacked the C code so that Fortran routines could be called
instead, producing the expected results.

> > (3) Through the judicious use of header files with compiler-
> > dependent flags,  we could accommodate the various naming
> > conventions used when the FORTRAN libraries were compiled (e.g.,
> > sgetrf_ or SGETRF).
> 
> That's already done!

Where? Even in the latest f2c'd source code that I downloaded from
SourceForge, I see all names written using the
lower-case-trailing-underscore convention (e.g., dgeqrf_). The Intel MKL was
compiled from Fortran source using the upper-case-no-underscore convention
(e.g., DGEQRF). If I replace dgeqrf_ with DGEQRF in dlapack_lite.c (and a
few other tweaks), then the subsequent link with the IMKL succeeds.

============================
Ray Beausoleil
Hewlett-Packard Laboratories
mailto:beausol at hpl.hp.com
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