Reference documentation for deal.II version 9.4.0
PETScWrappers::PreconditionBlockJacobi Class Reference

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

Inheritance diagram for PETScWrappers::PreconditionBlockJacobi:
[legend]

## Public Member Functions

PreconditionBlockJacobi ()=default

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

PC pc

Mat matrix

## Subscriptor functionality

Classes derived from Subscriptor provide a facility to subscribe to this object. This is mostly used by the SmartPointer class.

void subscribe (std::atomic< bool > *const validity, const std::string &identifier="") const

void unsubscribe (std::atomic< bool > *const validity, const std::string &identifier="") const

unsigned int n_subscriptions () const

template<typename StreamType >
void list_subscribers (StreamType &stream) const

void list_subscribers () const

template<class Archive >
void serialize (Archive &ar, const unsigned int version)

using map_value_type = decltype(counter_map)::value_type

using map_iterator = decltype(counter_map)::iterator

std::atomic< unsigned intcounter

std::map< std::string, unsigned intcounter_map

std::vector< std::atomic< bool > * > validity_pointers

const std::type_info * object_info

static std::mutex mutex

static ::ExceptionBaseExcInUse (int arg1, std::string arg2, std::string arg3)

static ::ExceptionBaseExcNoSubscriber (std::string arg1, std::string arg2)

void check_no_subscribers () const noexcept

## 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 222 of file petsc_precondition.h.

## ◆ PreconditionBlockJacobi() [1/3]

 PETScWrappers::PreconditionBlockJacobi::PreconditionBlockJacobi ( )
default

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 petsc_precondition.cc.

## ◆ 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 petsc_precondition.cc.

## ◆ 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 petsc_precondition.cc.

## ◆ initialize() [2/2]

 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 197 of file petsc_precondition.cc.

## ◆ clear()

 void PETScWrappers::PreconditionBase::clear ( )
inherited

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

Definition at line 52 of file petsc_precondition.cc.

## ◆ vmult()

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

Apply the preconditioner once to the given src vector.

Definition at line 66 of file petsc_precondition.cc.

## ◆ Tvmult()

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

Apply the transpose preconditioner once to the given src vector.

Definition at line 76 of file petsc_precondition.cc.

## ◆ get_pc()

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

Definition at line 113 of file petsc_precondition.cc.

## ◆ create_pc()

 void PETScWrappers::PreconditionBase::create_pc ( )
protectedinherited

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

Definition at line 86 of file petsc_precondition.cc.

## ◆ operator Mat()

 PETScWrappers::PreconditionBase::operator Mat ( ) const
protectedinherited

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 petsc_precondition.cc.

## Member Data Documentation

protected

Store a copy of the flags for this particular preconditioner.

Definition at line 269 of file petsc_precondition.h.

## ◆ pc

 PC PETScWrappers::PreconditionBase::pc
protectedinherited

the PETSc preconditioner object

Definition at line 101 of file petsc_precondition.h.

## ◆ matrix

 Mat PETScWrappers::PreconditionBase::matrix
protectedinherited

A pointer to the matrix that acts as a preconditioner.

Definition at line 106 of file petsc_precondition.h.

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