TrilinosWrappers::PreconditionAMGMueLu::AdditionalData Struct Reference

#include <deal.II/lac/trilinos_precondition.h>

Public Member Functions
	AdditionalData (const bool elliptic=true, const unsigned int n_cycles=1, const bool w_cyle=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

Detailed Description

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 1743 of file trilinos_precondition.h.

Constructor & Destructor Documentation

AdditionalData()

TrilinosWrappers::PreconditionAMGMueLu::AdditionalData::AdditionalData	(	const bool	elliptic = true,
		const unsigned int	n_cycles = 1,
		const bool	w_cyle = 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 31 of file trilinos_precondition_muelu.cc.

Member Data Documentation

elliptic

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 1768 of file trilinos_precondition.h.

n_cycles

unsigned int TrilinosWrappers::PreconditionAMGMueLu::AdditionalData::n_cycles

Defines how many multigrid cycles should be performed by the preconditioner.

Definition at line 1774 of file trilinos_precondition.h.

w_cycle

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 1780 of file trilinos_precondition.h.

aggregation_threshold

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 1791 of file trilinos_precondition.h.

constant_modes

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 1799 of file trilinos_precondition.h.

smoother_sweeps

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 1811 of file trilinos_precondition.h.

smoother_overlap

unsigned int TrilinosWrappers::PreconditionAMGMueLu::AdditionalData::smoother_overlap

Determines the overlap in the SSOR/Chebyshev error smoother when run in parallel.

Definition at line 1817 of file trilinos_precondition.h.

output_details

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 1824 of file trilinos_precondition.h.

smoother_type

const char* TrilinosWrappers::PreconditionAMGMueLu::AdditionalData::smoother_type

Determines which smoother to use for the AMG cycle. Possibilities for smoother_type are the following:

• "Aztec"
• "IFPACK"
• "Jacobi"
• "ML symmetric Gauss-Seidel"
• "symmetric Gauss-Seidel"
• "ML Gauss-Seidel"
• "Gauss-Seidel"
• "block Gauss-Seidel"
• "symmetric block Gauss-Seidel"
• "Chebyshev"
• "MLS"
• "Hiptmair"
• "Amesos-KLU"
• "Amesos-Superlu"
• "Amesos-UMFPACK"
• "Amesos-Superludist"
• "Amesos-MUMPS"
• "user-defined"
• "SuperLU"
• "IFPACK-Chebyshev"
• "self"
• "do-nothing"
• "IC"
• "ICT"
• "ILU"
• "ILUT"
• "Block Chebyshev"
• "IFPACK-Block Chebyshev"

Definition at line 1860 of file trilinos_precondition.h.

coarse_type

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 1866 of file trilinos_precondition.h.

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The documentation for this struct was generated from the following files:

• deal.II/lac/trilinos_precondition.h
• source/lac/trilinos_precondition_muelu.cc