[PLUG] Matrix manipulation code in C or FORTRAN

[Grigsby, Garl]

So what is it you are attempting to calculate EigenValues for, if you don't mind me asking? It is so rare for me to run into people in a non-work setting that have ever heard of an eigenvalue, much less want to calculate one.

Garl

> -----Original Message-----
> From: Rich Shepard [mailto:rshepard at appl-ecosys.com]
> Sent: Wednesday, October 08, 2003 4:03 PM
> To: plug at lists.pdxlinux.org
> Subject: RE: [PLUG] Matrix manipulation code in C or FORTRAN
> 
> 
> On Wed, 8 Oct 2003, Grigsby, Garl wrote:
> 
> > As I understand it the GNU Scientific Library should have 
> functions for
> > doing eigenvalue extraction. I used to have a FORTRAN 
> library, but I can't
> > find it at the moment (Damnit I need to find a way to 
> organize all of this
> > software....). Here is a link for the GSL. Hope it helps.
> 
> Garl,
> 
>   That's one I checked. But, I answered my own question by 
> dredging from my
> memory a vague recall that either or both of R or Octave 
> would have eigen
> functions. They do.
> 
>   The R statistical system is the FOSS equivalent of S/S-PLUS 
> in the winduhs
> world. It is a _huge_ statistical programming language (as 
> Gri is a plotting
> language) and it has an 'eigen' function that handles both 
> sparse and full
> matrices. R functions can be called from other programs; I've 
> done this with
> GRASS to run statistics on spatial maps.
> 
>   Octave is the FOSS equivalent to MatLab. It, too, will calculate
> eigenvectors and eigenvalues of square matrices.
> 
>   I think that Octave would be good for stand-alone 
> calculations while R
> will be the way to incorporate the calcuations into a larger model.
> 
> Thanks for looking and replying,
> 
> Rich
> 
> Dr. Richard B. Shepard, President
> 
>                        Applied Ecosystem Services, Inc. (TM)
>             2404 SW 22nd Street | Troutdale, OR 97060-1247 | U.S.A.
>  + 1 503-667-4517 (voice) | + 1 503-667-8863 (fax) | 
> rshepard@appl-ecosys.com
>                          http://www.appl-ecosys.com/
> 
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