On Fri, 2 Dec 2016 at 16:12 Mitchell, Lawrence < lawrence.mitchell@imperial.ac.uk> wrote:
On 2 Dec 2016, at 16:01, Anna Kalogirou <a.kalogirou@leeds.ac.uk> wrote:
Linear firedrake_0_fieldsplit_3_ solve did not converge due to DIVERGED_DTOL iterations 35
The option
"fieldsplit_3_pc_factor_shift_type": "nonzero"
Given that LU with pivoting ought to invert the block unless it is singular, I think something funky is going on.
Can you additionally run with:
"fieldsplit_3_ksp_monitor_true_residual": True
(In passing, if you're using LU you should probably be setting the ksp_type of these sub solves to "preonly", so you don't bother iterating).
The function space is CG1. I believe that has diagonally dominant mass matrices so we shouldn't actually need pivotting.
Lawrence _______________________________________________ firedrake mailing list firedrake@imperial.ac.uk https://mailman.ic.ac.uk/mailman/listinfo/firedrake