Re: gslclapack

[James Bergstra <james dot bergstra at umontreal dot ca>]

On Wed, Mar 29, 2006 at 07:04:39PM +0100, J.J.Green wrote:
> I think the problem with calling fortran from C is that
> it is compiler, OS and (I think) architecture dependant.
> CLAPACK solves the portability problem, but as you have
> noticed, not the arcane interface which puts most poeple
> off using it.

Exactly the motivation for a gsl wrapper (or extension)!  A
gsl module would serve both as a gentle introduction to
using lapack, as well as a hook to place normal
documentation.

It seems to me that the largest barrier to a lapack wrapper
is that gsl_matrix is an implicitly row-major structure, so
that in general, arguments must be out-of-place transposed
before a lapack call.  Although this is not significant in
terms of either O(n) time or space,  the overhead is more
noticeable in the case of large numbers of calls with small
arguments.

Anyway, it seems like the concensus is that lapack is
annoying to use but good in theory, once it's working.  If
someone (eg. me) writes an extension that makes (at least
part of lapack) less annoying to use in practice, share with
the list?


James

PS.  My extension would probably introduce a column-major
version of gsl_matrix.

-- 
james bergstra
http://www-etud.iro.umontreal.ca/~bergstrj