Leo Butler wrote:
> Hello,
> I have encountered the following problem. I am unsure of its origins.
> The charpoly of the 6x6 matrix is (x^3-3x-1)^2, so the eigenvector
> problem can be solved symbolically (maple does it in < 1sec on my
> work desktop).
> Leo
>
>
> <session>
> Maxima 5.16.3 http://maxima.sourceforge.net
> Using Lisp GNU Common Lisp (GCL) GCL 2.6.8 (aka GCL)
> Distributed under the GNU Public License. See the file COPYING.
> Dedicated to the memory of William Schelter.
> The function bug_report() provides bug reporting information.
> (%i1) A : matrix([0, 0, -1, 0, 0, 0], [2, 0, 0, 0, 1, 0], [-4, 0, 0, -1,
> -1, 0], [0, -2, -1, 0, 0, -1], [1, 2, 0, 0, 0, 1], [-2, 1, 1, -2, 1,
> 0]);
> [ 0 0 - 1 0 0 0 ]
> [ ]
> [ 2 0 0 0 1 0 ]
> [ ]
> [ - 4 0 0 - 1 - 1 0 ]
> (%o1) [ ]
> [ 0 - 2 - 1 0 0 - 1 ]
> [ ]
> [ 1 2 0 0 0 1 ]
> [ ]
> [ - 2 1 1 - 2 1 0 ]
> (%i2) eigenvectors(A);
>
> Maxima encountered a Lisp error:
>
> Error in PROGN [or a callee]: Caught fatal error [memory may be
> damaged]
>
>
This doesn't help, but with cmucl, the problem is that algsys says the
system is too complicated to solve. I don't know why gcl crashes this
way. It shouldn't.
Ray