Interesting! I have also noticed that if I just slightly modify the matrix
m2, it again works efficiently.
Will someone direct the pariGP guys to this issue?
On Thursday, 6 September 2012 17:03:59 UTC+2, D. S. McNeil wrote:
>
> > That said, I am wondering if this is perhaps a bug in the default
> That said, I am wondering if this is perhaps a bug in the default
> implementation of determinant()?
> It seems strange to me that it takes 8 minutes to compute a determinant of a
> 34x34 matrix while other algorithms do it within a second.
Yeah, it looks like pari's Gauss-Bareiss takes foreve
Consider the following program
sage: G = graphs.OddGraph(4)
sage: G.spanning_trees_count()
336140
It takes approximately 8 minutes to compute the number of spanning trees using
this method. However, the number of spanning trees can be computed directly
from the charpoly of the respe
