[petsc-users] Equivalent of DMGetRefineLevel and DMGetCoarsenLevel for FAS

Smith, Barry F. bsmith at mcs.anl.gov
Tue Jul 10 16:15:07 CDT 2018

   Hm, you could always hunt through your list of auxiliary DMS to find something of the same size?

> On Jul 10, 2018, at 4:10 PM, zakaryah <zakaryah at gmail.com> wrote:
> 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.

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