Reference documentation for deal.II version GIT relicensing-660-g9ae06c0eb4 2024-05-17 13:10:02+00:00
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Public Types | Public Member Functions | Public Attributes | List of all members
PETScWrappers::PreconditionBoomerAMG::AdditionalData Struct Reference

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

Public Types

enum class  RelaxationType {
  Jacobi , sequentialGaussSeidel , seqboundaryGaussSeidel , SORJacobi ,
  backwardSORJacobi , symmetricSORJacobi , l1scaledSORJacobi , GaussianElimination ,
  l1GaussSeidel , backwardl1GaussSeidel , CG , Chebyshev ,
  FCFJacobi , l1scaledJacobi , None

Public Member Functions

 AdditionalData (const bool symmetric_operator=false, const double strong_threshold=0.25, const double max_row_sum=0.9, const unsigned int aggressive_coarsening_num_levels=0, const bool output_details=false, const RelaxationType relaxation_type_up=RelaxationType::SORJacobi, const RelaxationType relaxation_type_down=RelaxationType::SORJacobi, const RelaxationType relaxation_type_coarse=RelaxationType::GaussianElimination, const unsigned int n_sweeps_coarse=1, const double tol=0.0, const unsigned int max_iter=1, const bool w_cycle=false)

Public Attributes

bool symmetric_operator
double strong_threshold
double max_row_sum
unsigned int aggressive_coarsening_num_levels
bool output_details
RelaxationType relaxation_type_up
RelaxationType relaxation_type_down
RelaxationType relaxation_type_coarse
unsigned int n_sweeps_coarse
double tol
unsigned int max_iter
bool w_cycle

Detailed Description

Standardized data struct to pipe additional flags to the preconditioner.

Definition at line 627 of file petsc_precondition.h.

Member Enumeration Documentation

◆ RelaxationType

Defines the available relaxation types for BoomerAMG.


Definition at line 632 of file petsc_precondition.h.

Constructor & Destructor Documentation

◆ AdditionalData()

PETScWrappers::PreconditionBoomerAMG::AdditionalData::AdditionalData ( const bool  symmetric_operator = false,
const double  strong_threshold = 0.25,
const double  max_row_sum = 0.9,
const unsigned int  aggressive_coarsening_num_levels = 0,
const bool  output_details = false,
const RelaxationType  relaxation_type_up = RelaxationType::SORJacobi,
const RelaxationType  relaxation_type_down = RelaxationType::SORJacobi,
const RelaxationType  relaxation_type_coarse = RelaxationType::GaussianElimination,
const unsigned int  n_sweeps_coarse = 1,
const double  tol = 0.0,
const unsigned int  max_iter = 1,
const bool  w_cycle = false 

Constructor. Note that BoomerAMG offers a lot more options to set than what is exposed here.

Definition at line 427 of file

Member Data Documentation

◆ symmetric_operator

bool PETScWrappers::PreconditionBoomerAMG::AdditionalData::symmetric_operator

Set this flag to true if you have a symmetric system matrix and you want to use a solver which assumes a symmetric preconditioner like CG.

Definition at line 675 of file petsc_precondition.h.

◆ strong_threshold

double PETScWrappers::PreconditionBoomerAMG::AdditionalData::strong_threshold

Threshold of when nodes are considered strongly connected. See HYPRE_BoomerAMGSetStrongThreshold(). Recommended values are 0.25 for 2d and 0.5 for 3d problems, but it is problem dependent.

Definition at line 682 of file petsc_precondition.h.

◆ max_row_sum

double PETScWrappers::PreconditionBoomerAMG::AdditionalData::max_row_sum

If set to a value smaller than 1.0 then diagonally dominant parts of the matrix are treated as having no strongly connected nodes. If the row sum weighted by the diagonal entry is bigger than the given value, it is considered diagonally dominant. This feature is turned of by setting the value to 1.0. This is the default as some matrices can result in having only diagonally dominant entries and thus no multigrid levels are constructed. The default in BoomerAMG for this is 0.9. When you try this, check for a reasonable number of levels created.

Definition at line 695 of file petsc_precondition.h.

◆ aggressive_coarsening_num_levels

unsigned int PETScWrappers::PreconditionBoomerAMG::AdditionalData::aggressive_coarsening_num_levels

Number of levels of aggressive coarsening. Increasing this value reduces the construction time and memory requirements but may decrease effectiveness.

Definition at line 702 of file petsc_precondition.h.

◆ output_details

bool PETScWrappers::PreconditionBoomerAMG::AdditionalData::output_details

Setting this flag to true produces debug output from HYPRE, when the preconditioner is constructed.

Definition at line 708 of file petsc_precondition.h.

◆ relaxation_type_up

RelaxationType PETScWrappers::PreconditionBoomerAMG::AdditionalData::relaxation_type_up

Choose relaxation type up.

Definition at line 713 of file petsc_precondition.h.

◆ relaxation_type_down

RelaxationType PETScWrappers::PreconditionBoomerAMG::AdditionalData::relaxation_type_down

Choose relaxation type down.

Definition at line 718 of file petsc_precondition.h.

◆ relaxation_type_coarse

RelaxationType PETScWrappers::PreconditionBoomerAMG::AdditionalData::relaxation_type_coarse

Choose relaxation type coarse.

Definition at line 723 of file petsc_precondition.h.

◆ n_sweeps_coarse

unsigned int PETScWrappers::PreconditionBoomerAMG::AdditionalData::n_sweeps_coarse

Choose number of sweeps on coarse grid.

Definition at line 728 of file petsc_precondition.h.

◆ tol

double PETScWrappers::PreconditionBoomerAMG::AdditionalData::tol

Choose BommerAMG tolerance.

Definition at line 733 of file petsc_precondition.h.

◆ max_iter

unsigned int PETScWrappers::PreconditionBoomerAMG::AdditionalData::max_iter

Choose BommerAMG maximum number of cycles.

Definition at line 738 of file petsc_precondition.h.

◆ w_cycle

bool PETScWrappers::PreconditionBoomerAMG::AdditionalData::w_cycle

Defines whether a w-cycle should be used instead of the standard setting of a v-cycle.

Definition at line 744 of file petsc_precondition.h.

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