[petsc-users] Is PCMG a generic PC object ?

[Vijay S. Mahadevan]

Hi all,

I was wondering whether the MG preconditioner object is generic enough
to work out of the box like say ILU or SOR.  To elaborate on this, if
I can provide the number of levels, restriction and prolongation
operators for each level and the system operators along with vectors
allocated for solution and rhs, would it work as a preconditioner for
my given problem and a prescribed rhs at the finest level of PCMG. Or
does it need some knowledge of the fine and coarser meshes to perform
the MG operations correctly ?

All the examples I've seen using MG in petsc involve the DA and DMMG
objects and since I use my own mesh and corresponding discretization
code for an elliptic system, I'm curious about this usage. It would
not be terribly difficult to write my own framework to do a simple
V-cycle with my existing framework but since petsc already provides
this functionality along with different types of MG solves (with
verified code!), I really want to use it for my system. Any help
and/or pointers are welcome.

Thanks,
vijay