Re: Symmetric matrices only!

[Ken Thomas <kst@ecs.soton.ac.uk>]

On Apr 18, 5:30 am, Gautier <gaut...@fakeaddress.nil> wrote:
> amado.al...@gmail.com:
>
> > The eigenvector solvers in Ada.Numerics.Generic_Real_Arrays require
> > *symmetric* matrices! This is extremely silly. The world is full of
> > nonsymmetric matrices. I've got a bunch of them to solve. Some very
> > large, e.g. 1000x1000. Suggestions welcome. Thanks a lot.
>
> As other people answered, solving a symmetric matrix is another science than a
> asymmetric one. But also when the matrices get big, other storages (than array
> (Integer range <>, Integer range <>) of...) can be a better solution, like band
> or sparse matrices. In some areas a 10_000 x 10_000 matrix is a toy one, for
> testing small examples (e.g. solving a physics equation on a 100x100 grid)...
> ______________________________________________________________
> Gautier         --http://www.mysunrise.ch/users/gdm/index.htm
> Ada programming --http://www.mysunrise.ch/users/gdm/gsoft.htm
>
> NB: For a direct answer, e-mail address on the Web site!

What you can do is write an interface to the LAPACK routine _GEEV (or
similar); it means needing an installation of LAPACK and BLAS. But if
you are using Generic_Real_Arrays you will need to link up with these
libraries anyway.

Duncan Sands produced bindings to BLAS and I extended some to cover
the LAPACK material I needed. They are not complete  just created on
demand. I could send these if they would help.

Ada is very good in the way it can define interfaces to numerical
software.