James Bergstra
Wed Mar 29 18:51:00 GMT 2006

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

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

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?


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

james bergstra

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