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
