Subject: Help with very very slow determinant calcuation
From: Bernard Hurley
Date: Sat, 06 Aug 2011 10:18:59 +0100
On Wed, 2011-08-03 at 19:26 -0700, Nghia Ho wrote:
> Hi all,
>
>
> I'm trying to run the determinant() function a 10x10 matrix that contains all symbolic values. I've searched through the mailing list to find a solution. I've tried ratmax:true and newdet(), but it is still taking forever. In fact, as of writing now it has been going for over 12 hours and still hasn't finished! Is the determinant doing other stuff besides doing the multiplication and addition? Is it trying to simplify/factorise as it goes along?
>
> Nghia
>
> _______________________________________________
To evaluate a 10x10 determinant containing independent symbols requires
10! = 3628800 multiplications, as well as additions etc. I would expect
this to take a very very long time. There are ways of cutting down on
this in a numerical matrix or if there are relationships between the
symbols.
Bernard.