6 Nov
2015
6 Nov
'15
12:39 p.m.
You can run with -info and grep on GAMG, and send this. If you are shifting a matrix then it can/will get indefinite. If it is just a mass matrix then Jacobi should converge quickly - does it? On Fri, Nov 6, 2015 at 9:35 AM, Denis Davydov <[email protected]> wrote:
On 6 Nov 2015, at 17:39, Barry Smith <[email protected]> wrote:
If it is a true mass matrix in the finite element sense of the word then it should be very well conditioned and one definitely would not use something like GAMG on. Jacobi + CG or maybe SSOR + CG should converge rapidly
That I understand and absolutely agree. It just does not explain why GAMG would fail, especially on 4 cores and not on 8.
Regards, Denis.