[petsc-users] Algebraic multigrid with fieldsplit smoother

[David Nolte]

Dear all,

in the context of Navier-Stokes problems using FEM, I am interested in
trying a "coupled AMG" method, where the smoother on each (but the
coarse) level uses a Schur complement fieldsplit PC (I am thinking of
some variant of SIMPLE). Is this possible with gamg/ml/hypre?
I would set, for instance,

    -mg_levels_pc_type fieldsplit
    -mg_levels_pc_fieldsplit_type schur
    -mg_levels_pc_fieldsplit_schur_precondition selfp
   
and set the IS for the Fieldsplit in the code. I only have the IS for
the fine level, though. Would I have to specify the correct IS for the
fieldsplit of each sublevel (don't have that information)? How can this
be done?

Thanks a lot in advance!
David