* Do you set:
PetscCall(MatSetOption(Amat, MAT_SPD, PETSC_TRUE));
PetscCall(MatSetOption(Amat, MAT_SPD_ETERNAL, PETSC_TRUE));
Do that to get CG Eigen estimates. Outright failure is usually caused by a
bad Eigen estimate.
-pc_gamg_esteig_ksp_monitor_singular_value
Will print out the
You can -pc_gamg_threshold .02 to slow the coarsening and either stronger
smoother or increase number of iterations used for estimation (or increase
tolerance). I assume your system is SPD and you've set the near-null space.
Blaise Bourdin writes:
> Hi,
>
> I am having issue with GAMG for
Hi,
I am having issue with GAMG for some very ill-conditioned 2D linearized
elasticity problems (sharp variation of elastic moduli with thin regions of
nearly incompressible material). I use snes_type newtonls, linesearch_type cp,
and pc_type gamg without any further options. pc_type Jacobi
