[petsc-users] Scalable Direct Coarse Solver for PCMG

[domenico.borzacchiello at univ-st-etienne.fr]

Hi,
I'm solving Stokes problem in a coupled way with Vanka smoothers and MG
and I need to choose a solver for the coarse grid correction. I've tried
with an iterative solver too but it works only fairly on regular grids
with few processes and otherwise performs very poorly with communication
dominated calculations.

I'd like to know if the tufo-fischer direct solver is suitable to solve
saddle problems. The matrix is full rank.

Thank you,
Domenico