PreconditionSelector< MatrixType, VectorType > Class Template Reference

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

Inheritance diagram for PreconditionSelector< MatrixType, VectorType >:

Public Types
using	size_type = typename MatrixType::size_type

Public Member Functions
	PreconditionSelector (const std::string &preconditioning, const typename VectorType::value_type &omega=1.)
virtual	~PreconditionSelector () override
void	use_matrix (const MatrixType &M)
size_type	m () const
size_type	n () const
virtual void	vmult (VectorType &dst, const VectorType &src) const
virtual void	Tvmult (VectorType &dst, const VectorType &src) const

Static Public Member Functions
static std::string	get_precondition_names ()
static ::ExceptionBase &	ExcNoMatrixGivenToUse ()

Protected Attributes
std::string	preconditioning

Private Attributes
SmartPointer< const MatrixType, PreconditionSelector< MatrixType, VectorType > >	A
const VectorType::value_type	omega

Subscriptor functionality
Classes derived from Subscriptor provide a facility to subscribe to this object. This is mostly used by the SmartPointer class.
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
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)
static ::ExceptionBase &	ExcInUse (int arg1, std::string arg2, std::string arg3)
static ::ExceptionBase &	ExcNoSubscriber (std::string arg1, std::string arg2)
using	map_value_type = decltype(counter_map)::value_type
using	map_iterator = decltype(counter_map)::iterator
static std::mutex	mutex
void	check_no_subscribers () const noexcept

Detailed Description

template<typename MatrixType = SparseMatrix<double>, typename VectorType = ::Vector<double>>
class PreconditionSelector< MatrixType, VectorType >

Selects the preconditioner. The constructor of this class takes the name of the preconditioning and the damping parameter omega of the preconditioning and the use_matrix function takes the matrix that is used by the matrix-builtin precondition functions. Each time, the operator() function is called, this preselected preconditioner, this matrix and this omega is used for the preconditioning. This class is designed for being used as argument of the solve function of a Solver and it covers the selection of all matrix-builtin precondition functions. The selection of other preconditioners, like BlockSOR or ILU should be handled in derived classes by the user.

Usage

The simplest use of this class is the following:

// generate a @p SolverControl and a @p VectorMemory
SolverControl control;
VectorMemory<Vector<double> > memory;
 
// generate a solver
SolverCG<SparseMatrix<double>, Vector<double> > solver(control, memory);
 
// generate a @p PreconditionSelector
PreconditionSelector<SparseMatrix<double>, Vector<double> >
  preconditioning("jacobi", 1.);
 
// give a matrix whose diagonal entries are to be used for the
// preconditioning. Generally the matrix of the linear equation system Ax=b.
preconditioning.use_matrix(A);
 
// call the @p solve function with this preconditioning as last argument
solver.solve(A,x,b,preconditioning);

The same example where also the SolverSelector class is used reads

// generate a @p SolverControl and a @p VectorMemory
SolverControl control;
VectorMemory<Vector<double> > memory;
 
// generate a @p SolverSelector that calls the @p SolverCG
SolverSelector<SparseMatrix<double>, Vector<double> >
  solver_selector("cg", control, memory);
 
// generate a @p PreconditionSelector
PreconditionSelector<SparseMatrix<double>, Vector<double> >
  preconditioning("jacobi", 1.);
 
preconditioning.use_matrix(A);
 
solver_selector.solve(A,x,b,preconditioning);

Now the use of the SolverSelector in combination with the PreconditionSelector allows the user to select both, the solver and the preconditioner, at the beginning of their program and each time the solver is started (that is several times e.g. in a nonlinear iteration) this preselected solver and preconditioner is called.

Definition at line 100 of file precondition_selector.h.

---

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

• include/deal.II/lac/precondition_selector.h