From help-request at octave dot org Thu Jan  5 19:50:07 2006
Subject: Re: rational numbers only
From: Paul Kienzle <pkienzle at users dot sourceforge dot net>
To: "John W. Eaton" <jwe at bevo dot che dot wisc dot edu>
Cc: help at octave dot org, Jordi Gutierrez Hermoso <jordigh@gmail.com>
Date: Thu, 5 Jan 2006 20:48:27 -0500


On Jan 5, 2006, at 4:46 PM, John W. Eaton wrote:

> On  5-Jan-2006, Jordi Gutierrez Hermoso wrote:
>
> | On 1/5/06, Jorge Barros de Abreu <ficmatin01 at solar dot com dot br> wrote:
> | > Hi.
> | >
> | > ?????Which the variable name that force maxima to work with 
> ratonal numbers
> | > only???
> |
> | Octave really isn't built for that kind of operations. There are
> | functions that do it as other people in this thread have mentioned,
> | but if you want a symbolic calculator, you're better off using a
> | dedicated CAS like Maxima or YACAS.
>
> You could also write a new user-defined data type for rational
> numbers.  Simple arithmetic for scalars and maybe even matrices would
> not be too hard.  But unless there are existing libraries for other
> operations, it would be a lot of work to get something like svd of a
> rational matrix working (if that would even make sense).

tnt+jama provide template based SVD, QR, LU, EIG and CHOL.

I had to do some mods to make it accept 100 digit floats, but these 
should also work for a rational type.  Anyone who wants to work on this 
(e.g., for vpa support) should let me know and I can send the patches.

- Paul



-------------------------------------------------------------
Octave is freely available under the terms of the GNU GPL.

Octave's home on the web:  http://www.octave.org
How to fund new projects:  http://www.octave.org/funding.html
Subscription information:  http://www.octave.org/archive.html
-------------------------------------------------------------