[petsc-users] Auxiliary fields for multigrid

[Dave May]

On Fri, 17 Nov 2017 at 04:26, zakaryah . <zakaryah at gmail.com> wrote:

> I have equations which depend on some external data.  I'm not sure about
> the approach for making this compatible with multigrid - i.e. making sure
> those external fields are properly refined/coarsened.
>

Multi grid does not strictly require you to restrict your external data.
For example (I) algebraic mg (PCGAMG) only requires only the fine level
operator: (I) you can define coarse level operators with geometric mg using
Galerkin projection. The latter only requires one to specify how to
interpolate your DM fields from fine to coarse (which PLEX and DA provide).

Why not try these out for your problem first?


Are there PETSc examples that do this?
>

Not that I'm aware off. Most use Galerkin or rediscretize the operator on
the coarser levels.

Thanks,
  Dave

>
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