[GRASS-user] Re: BLAS/LAPACK

[Glynn Clements]

Brad Douglas wrote:

> > > > Does that mean that i.fft and i.fft will not build or work properly
> > > > using gfortran coming with GCC 4.0.3? Is that an issue only with 64 bit
> > > > systems?
> > > 
> > > It's a GCC issue.  If you want i.fft/i.ifft, you need LAPACK/BLAS
> > > support,
> > 
> > No you don't. i.fft and i.ifft require FFTW, but they don't require
> > LAPACK/BLAS. Nothing in GRASS currently requires BLAS/LAPACK.
> 
> Copying thread to devel and changing subject...
> 
> Oops!  I should have checked before I wrote.  Yes, FFTW is required, not
> BLAS/LAPACK.
> 
> I do have a few imagery modules I want to finish, but I moved on to
> something else once BLAS/LAPACK became an issue.  I've implemented a few
> more routines for the imagery spectral modules, but it was problematic.
> What are the alternatives, other than very, very patiently waiting for
> gcc4 to catch up (this will be some time from what I have gathered from
> the gcc mailing lists)?

The alternatives are:

1. Use gcc 3.x.

2. Figure out how to call Fortran from C with gcc 4.x without any help
from the gcc developers.

Regarding #1: if the Fortran changes between 3.x and 4.x are
significant, you may also have to compile BLAS/LAPACK with 3.x.

-- 
Glynn Clements <glynn at gclements.plus.com>