Re: Sparse-merge

[Richard Hindmarsh]

David Bateman wrote:

> John W. Eaton wrote:
>
> > | Thanks. Will 2.9.x (or does the main trunk) have an interface to 
> > ARPACK | (e.g. through "eigs"), or is anyone working on this?
> >
> > Not yet.  SEe the list of projects for sparse matrices in the file
> >
> >  http://www.octave.org/cgi-bin/viewcvs.cgi/octave/PROJECTS?rev=1.60&view=auto 
>
> ARPACK is definitely on the todo list. It is a complete lack of time 
> at the moment that will prevent me from doing something here.
>
>
> If you want to do the ARPACK interfacing, I'd welcome the help and 
> would be willing to vet the code and give pointers.
I could possibly do it - I used ARPACK before "eigs" appeared in Matlab 
and have written .mex files though not .oct. Am motivated but short of time.

A quick look at "eigs" in Matlab shows that "eigs.m" calls an interface 
routine called "arpackc.dll" (or whatever suffix). It also looks as 
though "eigs" would be largely useable in Octave. I guess that an Octave 
"arpackc" would not be too difficult to write but what is then one 
expected to do - rewrite "eigs" so that it doesn't look like the Matlab 
one?

The same thing arises with other routines on the "sparse" to-do list, 
e.g. the conjugate-gradient solvers "cgs" etc. They look as though the 
Matlab versions would work more or less out of the (Matlab) box. Here 
the copyright aspect may be less relevant as "cgs.m", "bicgs.m" etc. are 
obtainable from netlib anyhow

"Templates for the
%     Solution of Linear Systems: Building Blocks for Iterative
%     Methods", Barrett, Berry, Chan, Demmel, Donato, Dongarra,
%     Eijkhout, Pozo, Romine, and van der Vorst, SIAM Publications,
%     1993. (ftp netlib2.cs.utk.edu; cd linalg; get templates.ps)

Regards
Richard



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