![]() |
Reference documentation for deal.II version 9.6.2
|
#include <deal.II/lac/trilinos_precondition.h>
Public Member Functions | |
AdditionalData (const bool elliptic=true, const unsigned int n_cycles=1, const bool w_cycle=false, const double aggregation_threshold=1e-4, const std::vector< std::vector< bool > > &constant_modes=std::vector< std::vector< bool > >(0), const unsigned int smoother_sweeps=2, const unsigned int smoother_overlap=0, const bool output_details=false, const char *smoother_type="Chebyshev", const char *coarse_type="Amesos-KLU") |
Public Attributes | |
bool | elliptic |
unsigned int | n_cycles |
bool | w_cycle |
double | aggregation_threshold |
std::vector< std::vector< bool > > | constant_modes |
unsigned int | smoother_sweeps |
unsigned int | smoother_overlap |
bool | output_details |
const char * | smoother_type |
const char * | coarse_type |
A data structure that is used to control details of how the algebraic multigrid is set up. The flags detailed in here are then passed to the Trilinos MueLu implementation. A structure of the current type are passed to the constructor of PreconditionAMGMueLu.
Definition at line 1714 of file trilinos_precondition.h.
TrilinosWrappers::PreconditionAMGMueLu::AdditionalData::AdditionalData | ( | const bool | elliptic = true, |
const unsigned int | n_cycles = 1, | ||
const bool | w_cycle = false, | ||
const double | aggregation_threshold = 1e-4, | ||
const std::vector< std::vector< bool > > & | constant_modes = std::vector<std::vector<bool>>(0), | ||
const unsigned int | smoother_sweeps = 2, | ||
const unsigned int | smoother_overlap = 0, | ||
const bool | output_details = false, | ||
const char * | smoother_type = "Chebyshev", | ||
const char * | coarse_type = "Amesos-KLU" ) |
Constructor. By default, we pretend to work on elliptic problems with linear finite elements on a scalar equation.
Definition at line 30 of file trilinos_precondition_muelu.cc.
bool TrilinosWrappers::PreconditionAMGMueLu::AdditionalData::elliptic |
Determines whether the AMG preconditioner should be optimized for elliptic problems (MueLu option smoothed aggregation SA, using a Chebyshev smoother) or for non-elliptic problems (MueLu option non-symmetric smoothed aggregation NSSA, smoother is SSOR with underrelaxation).
Definition at line 1739 of file trilinos_precondition.h.
unsigned int TrilinosWrappers::PreconditionAMGMueLu::AdditionalData::n_cycles |
Defines how many multigrid cycles should be performed by the preconditioner.
Definition at line 1745 of file trilinos_precondition.h.
bool TrilinosWrappers::PreconditionAMGMueLu::AdditionalData::w_cycle |
Defines whether a w-cycle should be used instead of the standard setting of a v-cycle.
Definition at line 1751 of file trilinos_precondition.h.
double TrilinosWrappers::PreconditionAMGMueLu::AdditionalData::aggregation_threshold |
This threshold tells the AMG setup how the coarsening should be performed. In the AMG used by MueLu, all points that strongly couple with the tentative coarse-level point form one aggregate. The term strong coupling is controlled by the variable aggregation_threshold, meaning that all elements that are not smaller than aggregation_threshold times the diagonal element do couple strongly.
Definition at line 1762 of file trilinos_precondition.h.
std::vector<std::vector<bool> > TrilinosWrappers::PreconditionAMGMueLu::AdditionalData::constant_modes |
Specifies the constant modes (near null space) of the matrix. This parameter tells AMG whether we work on a scalar equation (where the near null space only consists of ones) or on a vector-valued equation.
Definition at line 1770 of file trilinos_precondition.h.
unsigned int TrilinosWrappers::PreconditionAMGMueLu::AdditionalData::smoother_sweeps |
Determines how many sweeps of the smoother should be performed. When the flag elliptic is set to true, i.e., for elliptic or almost elliptic problems, the polynomial degree of the Chebyshev smoother is set to smoother_sweeps. The term sweeps refers to the number of matrix-vector products performed in the Chebyshev case. In the non-elliptic case, smoother_sweeps sets the number of SSOR relaxation sweeps for post-smoothing to be performed.
Definition at line 1782 of file trilinos_precondition.h.
unsigned int TrilinosWrappers::PreconditionAMGMueLu::AdditionalData::smoother_overlap |
Determines the overlap in the SSOR/Chebyshev error smoother when run in parallel.
Definition at line 1788 of file trilinos_precondition.h.
bool TrilinosWrappers::PreconditionAMGMueLu::AdditionalData::output_details |
If this flag is set to true, then internal information from the ML preconditioner is printed to screen. This can be useful when debugging the preconditioner.
Definition at line 1795 of file trilinos_precondition.h.
const char* TrilinosWrappers::PreconditionAMGMueLu::AdditionalData::smoother_type |
Determines which smoother to use for the AMG cycle. Possibilities for smoother_type are the following:
Definition at line 1831 of file trilinos_precondition.h.
const char* TrilinosWrappers::PreconditionAMGMueLu::AdditionalData::coarse_type |
Determines which solver to use on the coarsest level. The same settings as for the smoother type are possible.
Definition at line 1837 of file trilinos_precondition.h.