PETScWrappers::PreconditionBlockJacobi Class Reference

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

Inheritance diagram for PETScWrappers::PreconditionBlockJacobi:

Classes
struct	AdditionalData

Public Member Functions
	PreconditionBlockJacobi ()=default
	PreconditionBlockJacobi (const MatrixBase &matrix, const AdditionalData &additional_data=AdditionalData())
	PreconditionBlockJacobi (const MPI_Comm communicator, const AdditionalData &additional_data=AdditionalData())
void	initialize (const MatrixBase &matrix, const AdditionalData &additional_data=AdditionalData())
Public Member Functions inherited from PETScWrappers::PreconditionerBase
	PreconditionerBase ()
virtual	~PreconditionerBase ()
void	clear ()
void	vmult (VectorBase &dst, const VectorBase &src) const
const PC &	get_pc () const

Protected Member Functions
void	initialize ()
Protected Member Functions inherited from PETScWrappers::PreconditionerBase
void	create_pc ()
	operator Mat () const

Protected Attributes
AdditionalData	additional_data
Protected Attributes inherited from PETScWrappers::PreconditionerBase
PC	pc
Mat	matrix

Detailed Description

A class that implements the interface to use the PETSc Block Jacobi preconditioner. PETSc defines the term "block Jacobi" as a preconditioner in which it looks at a number of diagonal blocks of the matrix and then defines a preconditioner in which the preconditioner matrix has the same block structure as only these diagonal blocks, and each diagonal block of the preconditioner is an approximation of the inverse of the corresponding block of the original matrix. The blocking structure of the matrix is determined by the association of degrees of freedom to the individual processors in an MPI-parallel job. If you use this preconditioner on a sequential job (or an MPI job with only one process) then the entire matrix is the only block.

By default, PETSc uses an ILU(0) decomposition of each diagonal block of the matrix for preconditioning. This can be changed, as is explained in the relevant section of the PETSc manual, but is not implemented here.

See the comment in the base class PreconditionerBase for when this preconditioner may or may not work.

Author

Wolfgang Bangerth, Timo Heister, 2004, 2011

Definition at line 218 of file petsc_precondition.h.

Constructor & Destructor Documentation

PETScWrappers::PreconditionBlockJacobi::PreconditionBlockJacobi ( )

default

Empty Constructor. You need to call initialize() before using this object.

PreconditionBlockJacobi< MatrixType, inverse_type >::PreconditionBlockJacobi	(	const MatrixBase &	matrix,
		const AdditionalData &	additional_data = AdditionalData()
	)

Constructor. Take the matrix which is used to form the preconditioner, and additional flags if there are any.

Definition at line 179 of file petsc_precondition.cc.

PreconditionBlockJacobi< MatrixType, inverse_type >::PreconditionBlockJacobi	(	const MPI_Comm	communicator,
		const AdditionalData &	additional_data = AdditionalData()
	)

Same as above but without setting a matrix to form the preconditioner. Intended to be used with SLEPc objects.

Definition at line 165 of file petsc_precondition.cc.

Member Function Documentation

void PreconditionBlockJacobi< MatrixType, inverse_type >::initialize	(	const MatrixBase &	matrix,
		const AdditionalData &	additional_data = AdditionalData()
	)

Initialize the preconditioner object and calculate all data that is necessary for applying it in a solver. This function is automatically called when calling the constructor with the same arguments and is only used if you create the preconditioner without arguments.

Definition at line 198 of file petsc_precondition.cc.

void PreconditionBlockJacobi< MatrixType, inverse_type >::initialize ( )

protected

Initialize the preconditioner object without knowing a particular matrix. This function sets up appropriate parameters to the underlying PETSc object after it has been created.

Definition at line 187 of file petsc_precondition.cc.

Member Data Documentation

AdditionalData PETScWrappers::PreconditionBlockJacobi::additional_data

protected

Store a copy of the flags for this particular preconditioner.

Definition at line 265 of file petsc_precondition.h.

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

• deal.II/lac/petsc_precondition.h
• /mnt/data/darndt/Sources/dealii-clang-6.0.0/source/lac/petsc_precondition.cc