Re: Another problem with matrix inversion

[Bill Allombert <Bill.Allombert@math.u-bordeaux1.fr>]

On Wed, May 27, 2009 at 12:07:23AM +0200, Bill Allombert wrote:
> On Mon, May 25, 2009 at 10:22:39AM +0200, Lorenz Minder wrote:
> > Hi,
> > 
> > I would be interested in the numbers, if you still have them at hand.
> > What I noticed is that matdet() (when using slow Gaussian elimination)
> > is still usable on a slow machine, when matadjoint(,1) wouldn't work for
> > me even on a really fast machine.  (It was very slow, but the worse
> > thing was that it would need way too much RAM.)
> 
> Well, it is a O(n^4) algorithm instead of O(n^3) so it is not
> going to be fast, but I think the problem is that RgX_RgM_eval_i is very
> inefficient and waste stack space (we should use Brent&Kung).

OK, so now I have implemented Brent&Kung for RgX_RgM_eval, so performance
are better now. Maybe it also use less memory, because I added garbage
collection.

Cheers,
Bill.