Too bad. I really need those determinants. Will
sage -upgrade
magically put things right for me?
I feel hesitant to spend another day compiling sage.
On Nov 25, 1:14 pm, Florent Hivert <florent.hiv...@univ-rouen.fr>
wrote:
> > [...]
>
> > > This looks like an after-effect of ticket #6441. Sebastian Pancratz
> > > wrote some very fast code to compute determinants over general
> > > commutative rings, which proceeds by computing the characteristic
> > > polynomial first. When doing this for symbolic matrices it needs to
> > > choose a variable name that won't conflict with anything, so it uses
> > > "A0123456789". This shouldn't leak out into the output, but it looks
> > > like it has done here.
>
> > Which seems to have been solved in sage 4.2.1 by
>
> > changeset: 13301:2c11d19e337f
> > user: Mike Hansen <mhan...@gmail.com>
> > date: Tue Nov 03 13:45:09 2009 +0700
> > summary: Trac #5639: minpoly of symbolic matrices is broken
>
> > Can anyone confirm this ?
>
> On linux 64 bits (OpenSuSE):
>
> ----------------------------------------------------------------------
> | Sage Version 4.2, Release Date: 2009-10-24 |
> | Type notebook() for the GUI, and license() for information. |
> ----------------------------------------------------------------------
> Loading Sage library. Current Mercurial branch is: combinat
> sage: m = matrix(4,4, SR(1))
> sage: m[3,3] -= var("t")
> sage: m.determinant()
> (t - 1)*(A0123456789 - 1)^3
>
> But:
>
> ----------------------------------------------------------------------
> | Sage Version 4.2.1, Release Date: 2009-11-14 |
> | Type notebook() for the GUI, and license() for information. |
> ----------------------------------------------------------------------
> Loading Sage library. Current Mercurial branch is: combinat
> sage: m = matrix(4,4, SR(1))
> sage: m[3,3] -= var("t")
> sage: m
>
> [ 1 0 0 0]
> [ 0 1 0 0]
> [ 0 0 1 0]
> [ 0 0 0 -t + 1]
> sage: m.determinant()
> -t + 1
>
> Cheers,
>
> Florent
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