Reference documentation for deal.II version Git 99efdf013c 2021-02-27 20:52:41 -0500
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Classes | Public Member Functions | Protected Member Functions | Protected Attributes | List of all members
PETScWrappers::PreconditionBlockJacobi Class Reference

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

Inheritance diagram for PETScWrappers::PreconditionBlockJacobi:


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())
void clear ()
void vmult (VectorBase &dst, const VectorBase &src) const
void Tvmult (VectorBase &dst, const VectorBase &src) const
const PC & get_pc () const

Protected Member Functions

void initialize ()
void create_pc ()
 operator Mat () const

Protected Attributes

AdditionalData additional_data
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 PreconditionBase for when this preconditioner may or may not work.

Definition at line 220 of file petsc_precondition.h.

Constructor & Destructor Documentation

◆ PreconditionBlockJacobi() [1/3]

PETScWrappers::PreconditionBlockJacobi::PreconditionBlockJacobi ( )

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

◆ PreconditionBlockJacobi() [2/3]

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 189 of file

◆ PreconditionBlockJacobi() [3/3]

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 175 of file

Member Function Documentation

◆ initialize() [1/2]

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 208 of file

◆ initialize() [2/2]

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

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 197 of file

◆ clear()

void PETScWrappers::PreconditionBase::clear ( )

Destroys the preconditioner, leaving an object like just after having called the constructor.

Definition at line 52 of file

◆ vmult()

void PETScWrappers::PreconditionBase::vmult ( VectorBase dst,
const VectorBase src 
) const

Apply the preconditioner once to the given src vector.

Definition at line 66 of file

◆ Tvmult()

void PETScWrappers::PreconditionBase::Tvmult ( VectorBase dst,
const VectorBase src 
) const

Apply the transpose preconditioner once to the given src vector.

Definition at line 76 of file

◆ get_pc()

const PC & PETScWrappers::PreconditionBase::get_pc ( ) const

Give access to the underlying PETSc object.

Definition at line 113 of file

◆ create_pc()

void PETScWrappers::PreconditionBase::create_pc ( )

Internal function to create the PETSc preconditioner object. Fails if called twice.

Definition at line 86 of file

◆ operator Mat()

PETScWrappers::PreconditionBase::operator Mat ( ) const

Conversion operator to get a representation of the matrix that represents this preconditioner. We use this inside the actual solver, where we need to pass this matrix to the PETSc solvers.

Definition at line 119 of file

Member Data Documentation

◆ additional_data

AdditionalData PETScWrappers::PreconditionBlockJacobi::additional_data

Store a copy of the flags for this particular preconditioner.

Definition at line 267 of file petsc_precondition.h.

◆ pc

PC PETScWrappers::PreconditionBase::pc

the PETSc preconditioner object

Definition at line 99 of file petsc_precondition.h.

◆ matrix

Mat PETScWrappers::PreconditionBase::matrix

A pointer to the matrix that acts as a preconditioner.

Definition at line 104 of file petsc_precondition.h.

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