Thank you Lawrence. The 1-layer case is non-singular so the 2-layer should also be non-singular, I would think. I made the change you suggested and that seemed to help a lot. Now I need to understand the solution. Cheers, Francis ------------------ Francis Poulin Associate Professor Department of Applied Mathematics University of Waterloo email: fpoulin@uwaterloo.ca Web: https://uwaterloo.ca/poulin-research-group/ Telephone: +1 519 888 4567 x32637 ________________________________ From: firedrake-bounces@imperial.ac.uk <firedrake-bounces@imperial.ac.uk> on behalf of Lawrence Mitchell <lawrence.mitchell@imperial.ac.uk> Sent: Wednesday, June 21, 2017 12:54:53 PM To: firedrake@imperial.ac.uk Subject: Re: [firedrake] problem solving a linear system On 21/06/17 17:00, Francis Poulin wrote:
Saving file at /QG2L-Stommel-psi-u-q.ipynb Linear firedrake_0_ solve did not converge due to DIVERGED_PCSETUP_FAILED iterations 0 PCSETUP_FAILED due to FACTOR_NUMERIC_ZEROPIVOT
This is your problem. You have a 0 on the diagonal of your operator. If you are sure it is non-singular, try adding: "pc_factor_mat_solver_package": "mumps" to your solver options. Lawrence _______________________________________________ firedrake mailing list firedrake@imperial.ac.uk https://mailman.ic.ac.uk/mailman/listinfo/firedrake