| -pc_nn_turn_off_first_balancing | - do not balance the residual before solving the local Neumann problems (this skips the first coarse grid solve in the preconditioner) | |
| -pc_nn_turn_off_second_balancing | - do not balance the solution solving the local Neumann problems (this skips the second coarse grid solve in the preconditioner) | |
| -pc_is_damp_fixed <fact> | - | |
| -pc_is_remove_nullspace_fixed | - | |
| -pc_is_set_damping_factor_floating <fact> | - | |
| -pc_is_not_damp_floating | - | |
| -pc_is_not_remove_nullspace_floating | - |
Unlike more 'conventional' Neumann-Neumann preconditioners this iterates over ALL the degrees of freedom, NOT just those on the interface (this allows the use of approximate solvers on the subdomains; though in our experience using approximate solvers is slower.).
Options for the coarse grid preconditioner can be set with -nn_coarse_pc_xxx Options for the Dirichlet subproblem preconditioner can be set with -is_localD_pc_xxx Options for the Neumann subproblem preconditioner can be set with -is_localN_pc_xxx
Contributed by Paulo Goldfeld