Reference documentation for deal.II version GIT 13632c9f70 2022-09-25 13:40:02+00:00
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

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

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

## Static Public Member Functions

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

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

## Protected Member Functions

void initialize ()

void create_pc ()

operator Mat () const

PC pc

Mat matrix

## Private Types

using map_value_type = decltype(counter_map)::value_type

using map_iterator = decltype(counter_map)::iterator

## Private Member Functions

void check_no_subscribers () const noexcept

## Private Attributes

std::atomic< unsigned int > counter

std::map< std::string, unsigned int > counter_map

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

const std::type_info * object_info

## Static Private Attributes

static std::mutex mutex

## 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 223 of file petsc_precondition.h.

## ◆ map_value_type

 using Subscriptor::map_value_type = decltype(counter_map)::value_type
privateinherited

The data type used in counter_map.

Definition at line 230 of file subscriptor.h.

## ◆ map_iterator

 using Subscriptor::map_iterator = decltype(counter_map)::iterator
privateinherited

The iterator type used in counter_map.

Definition at line 235 of file subscriptor.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

Give access to the underlying PETSc object.

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.

## ◆ subscribe()

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

Subscribes a user of the object by storing the pointer validity. The subscriber may be identified by text supplied as identifier.

Definition at line 136 of file subscriptor.cc.

## ◆ unsubscribe()

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

Unsubscribes a user from the object.

Note
The identifier and the validity pointer must be the same as the one supplied to subscribe().

Definition at line 156 of file subscriptor.cc.

## ◆ n_subscriptions()

 unsigned int Subscriptor::n_subscriptions ( ) const
inlineinherited

Return the present number of subscriptions to this object. This allows to use this class for reference counted lifetime determination where the last one to unsubscribe also deletes the object.

Definition at line 300 of file subscriptor.h.

## ◆ list_subscribers() [1/2]

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

List the subscribers to the input stream.

Definition at line 317 of file subscriptor.h.

## ◆ list_subscribers() [2/2]

 void Subscriptor::list_subscribers ( ) const
inherited

List the subscribers to deallog.

Definition at line 204 of file subscriptor.cc.

## ◆ serialize()

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

Read or write the data of this object to or from a stream for the purpose of serialization using the BOOST serialization library.

This function does not actually serialize any of the member variables of this class. The reason is that what this class stores is only who subscribes to this object, but who does so at the time of storing the contents of this object does not necessarily have anything to do with who subscribes to the object when it is restored. Consequently, we do not want to overwrite the subscribers at the time of restoring, and then there is no reason to write the subscribers out in the first place.

Definition at line 309 of file subscriptor.h.

## ◆ check_no_subscribers()

 void Subscriptor::check_no_subscribers ( ) const
privatenoexceptinherited

Check that there are no objects subscribing to this object. If this check passes then it is safe to destroy the current object. It this check fails then this function will either abort or print an error message to deallog (by using the AssertNothrow mechanism), but will not throw an exception.

Note
Since this function is just a consistency check it does nothing in release mode.
If this function is called when there is an uncaught exception then, rather than aborting, this function prints an error message to the standard error stream and returns.

Definition at line 53 of file subscriptor.cc.

## Member Data Documentation

protected

Store a copy of the flags for this particular preconditioner.

Definition at line 270 of file petsc_precondition.h.

## ◆ pc

 PC PETScWrappers::PreconditionBase::pc
protectedinherited

the PETSc preconditioner object

Definition at line 102 of file petsc_precondition.h.

## ◆ matrix

 Mat PETScWrappers::PreconditionBase::matrix
protectedinherited

A pointer to the matrix that acts as a preconditioner.

Definition at line 107 of file petsc_precondition.h.

## ◆ counter

 std::atomic Subscriptor::counter
mutableprivateinherited

Store the number of objects which subscribed to this object. Initially, this number is zero, and upon destruction it shall be zero again (i.e. all objects which subscribed should have unsubscribed again).

The creator (and owner) of an object is counted in the map below if HE manages to supply identification.

We use the mutable keyword in order to allow subscription to constant objects also.

This counter may be read from and written to concurrently in multithreaded code: hence we use the std::atomic class template.

Definition at line 219 of file subscriptor.h.

## ◆ counter_map

 std::map Subscriptor::counter_map
mutableprivateinherited

In this map, we count subscriptions for each different identification string supplied to subscribe().

Definition at line 225 of file subscriptor.h.

## ◆ validity_pointers

 std::vector *> Subscriptor::validity_pointers
mutableprivateinherited

In this vector, we store pointers to the validity bool in the SmartPointer objects that subscribe to this class.

Definition at line 241 of file subscriptor.h.

## ◆ object_info

 const std::type_info* Subscriptor::object_info
mutableprivateinherited

Pointer to the typeinfo object of this object, from which we can later deduce the class name. Since this information on the derived class is neither available in the destructor, nor in the constructor, we obtain it in between and store it here.

Definition at line 249 of file subscriptor.h.

## ◆ mutex

 std::mutex Subscriptor::mutex
staticprivateinherited

A mutex used to ensure data consistency when printing out the list of subscribers.

Definition at line 271 of file subscriptor.h.

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