I'm trying to incorporate auxiliary fields (in a DMDA) in a problem in
nonlinear elasticity, in a way which is compatible with multi-grid
techniques. The advice I got previously was to use DMCoarsenHookAdd and
DMRefineHookAdd. I finally managed to make sense of the example that Jed
pointed out (SNES ex48.c), which was helpful. However, I thought that
since the same coarsening and refinement would be used repeatedly, I could
just keep everything around at all times, like example KSP ex42.c, using
DMRefineHierarchy. I managed to get that working with grid sequencing.
However, I can't seem to generalize to FAS, because in my FormFunction
routine, I need to be able to determine which of the auxiliary DMs from the
hierarchy corresponds to the current scale. With grid sequencing, I could
use DMGetRefineLevel. Is it possible to do something similar with FAS? Is
it completely stupid to try to do it this way? Thanks for any help.
