[petsc-users] GAMG

[Jeremy Theler]

Hi! I want to use PCGAMG as a preconditioner for a 3D linear elasticity
problem (displacement-based FEM formulation) over an unstructured grid.
I am not using DMPlex, I just build the stiffness matrix myself and pass
it to PETSc.

I set MatSetBlockSize() to 3 and pass the node coordinates through
PCSetCoordinates(). But using gamg and gmres I get:

PETSc error 77-0 'Eigen estimator failed: DIVERGED_NANORINF at iteration
0' in /home/gtheler/libs/petsc-3.7.4/src/ksp/ksp/impls/cheby/cheby.c
KSPSolve_Chebyshev:440

Any suggestion? Another PC/KSP combination to try?

Thanks
--
jeremy