[petsc-users] PCMG Interpolation/Restriction Defaults

[Grosse-Bley, Paul]

The documentation says that

> The multigrid routines, which determine the solvers and interpolation/restriction operators that are used, are mandatory.

But using code that doesn't contain any multigrid-specific routines e.g. ex45 and running it with

-da_grid_x 129 -da_grid_y 129 -da_grid_z 129
-pc_type mg
-pc_mg_type multiplicative
-pc_mg_cycle_type v
-pc_mg_levels 5
...

seems to work fine and also not fall-back to algebraic multigrid/PCGAMG from what I see with -log_view.

What interpolation/restriction operators are used by default with PCMG?
Is it cleverly using the geometric information from DA?

Thanks,
Paul
 
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.mcs.anl.gov/pipermail/petsc-users/attachments/20230202/d022891c/attachment.html>