A class to handle Block diagonal preconditioners in a matrix-free implementation. More...

#include <blockoperator.hpp>

Inheritance diagram for mfem::BlockDiagonalPreconditioner:

Collaboration diagram for mfem::BlockDiagonalPreconditioner:

Public Member Functions
	BlockDiagonalPreconditioner (const Array< int > &offsets)
	Constructor that specifies the block structure.

void	SetDiagonalBlock (int iblock, Operator *op)
	Add a square block op in the block-entry (iblock, iblock).

virtual void	SetOperator (const Operator &op)
	This method is present since required by the abstract base class Solver.

int	NumBlocks () const
	Return the number of blocks.

Operator &	GetDiagonalBlock (int iblock)
	Return a reference to block i,i.

const Operator &	GetDiagonalBlock (int iblock) const
	Return a reference to block i,i (const version).

Array< int > &	Offsets ()
	Return the offsets for block starts.

const Array< int > &	Offsets () const
	Read only access to the offsets for block starts.

virtual void	Mult (const Vector &x, Vector &y) const
	Operator application.

virtual void	MultTranspose (const Vector &x, Vector &y) const
	Action of the transpose operator.

	~BlockDiagonalPreconditioner ()

Public Member Functions inherited from mfem::Solver
	Solver (int s=0, bool iter_mode=false)
	Initialize a square Solver with size s.

	Solver (int h, int w, bool iter_mode=false)
	Initialize a Solver with height h and width w.

Public Member Functions inherited from mfem::Operator
void	InitTVectors (const Operator Po, const Operator Ri, const Operator *Pi, Vector &x, Vector &b, Vector &X, Vector &B) const
	Initializes memory for true vectors of linear system.

	Operator (int s=0)
	Construct a square Operator with given size s (default 0).

	Operator (int h, int w)
	Construct an Operator with the given height (output size) and width (input size).

int	Height () const
	Get the height (size of output) of the Operator. Synonym with NumRows().

int	NumRows () const
	Get the number of rows (size of output) of the Operator. Synonym with Height().

int	Width () const
	Get the width (size of input) of the Operator. Synonym with NumCols().

int	NumCols () const
	Get the number of columns (size of input) of the Operator. Synonym with Width().

virtual MemoryClass	GetMemoryClass () const
	Return the MemoryClass preferred by the Operator.

virtual void	AddMult (const Vector &x, Vector &y, const real_t a=1.0) const
	Operator application: `y+=A(x)` (default) or `y+=a*A(x)`.

virtual void	AddMultTranspose (const Vector &x, Vector &y, const real_t a=1.0) const
	Operator transpose application: `y+=A^t(x)` (default) or `y+=a*A^t(x)`.

virtual void	ArrayMult (const Array< const Vector * > &X, Array< Vector * > &Y) const
	Operator application on a matrix: `Y=A(X)`.

virtual void	ArrayMultTranspose (const Array< const Vector * > &X, Array< Vector * > &Y) const
	Action of the transpose operator on a matrix: `Y=A^t(X)`.

virtual void	ArrayAddMult (const Array< const Vector * > &X, Array< Vector * > &Y, const real_t a=1.0) const
	Operator application on a matrix: `Y+=A(X)` (default) or `Y+=a*A(X)`.

virtual void	ArrayAddMultTranspose (const Array< const Vector * > &X, Array< Vector * > &Y, const real_t a=1.0) const
	Operator transpose application on a matrix: `Y+=A^t(X)` (default) or `Y+=a*A^t(X)`.

virtual Operator &	GetGradient (const Vector &x) const
	Evaluate the gradient operator at the point x. The default behavior in class Operator is to generate an error.

virtual void	AssembleDiagonal (Vector &diag) const
	Computes the diagonal entries into diag. Typically, this operation only makes sense for linear Operators. In some cases, only an approximation of the diagonal is computed.

virtual const Operator *	GetProlongation () const
	Prolongation operator from linear algebra (linear system) vectors, to input vectors for the operator. `NULL` means identity.

virtual const Operator *	GetRestriction () const
	Restriction operator from input vectors for the operator to linear algebra (linear system) vectors. `NULL` means identity.

virtual const Operator *	GetOutputProlongation () const
	Prolongation operator from linear algebra (linear system) vectors, to output vectors for the operator. `NULL` means identity.

virtual const Operator *	GetOutputRestrictionTranspose () const
	Transpose of GetOutputRestriction, directly available in this form to facilitate matrix-free RAP-type operators.

virtual const Operator *	GetOutputRestriction () const
	Restriction operator from output vectors for the operator to linear algebra (linear system) vectors. `NULL` means identity.

void	FormLinearSystem (const Array< int > &ess_tdof_list, Vector &x, Vector &b, Operator *&A, Vector &X, Vector &B, int copy_interior=0)
	Form a constrained linear system using a matrix-free approach.

void	FormRectangularLinearSystem (const Array< int > &trial_tdof_list, const Array< int > &test_tdof_list, Vector &x, Vector &b, Operator *&A, Vector &X, Vector &B)
	Form a column-constrained linear system using a matrix-free approach.

virtual void	RecoverFEMSolution (const Vector &X, const Vector &b, Vector &x)
	Reconstruct a solution vector x (e.g. a GridFunction) from the solution X of a constrained linear system obtained from Operator::FormLinearSystem() or Operator::FormRectangularLinearSystem().

void	FormSystemOperator (const Array< int > &ess_tdof_list, Operator *&A)
	Return in A a parallel (on truedofs) version of this square operator.

void	FormRectangularSystemOperator (const Array< int > &trial_tdof_list, const Array< int > &test_tdof_list, Operator *&A)
	Return in A a parallel (on truedofs) version of this rectangular operator (including constraints).

void	FormDiscreteOperator (Operator *&A)
	Return in A a parallel (on truedofs) version of this rectangular operator.

void	PrintMatlab (std::ostream &out, int n, int m=0) const
	Prints operator with input size n and output size m in Matlab format.

virtual void	PrintMatlab (std::ostream &out) const
	Prints operator in Matlab format.

virtual	~Operator ()
	Virtual destructor.

Type	GetType () const
	Return the type ID of the Operator class.

Public Attributes
int	owns_blocks

Public Attributes inherited from mfem::Solver
bool	iterative_mode
	If true, use the second argument of Mult() as an initial guess.

Additional Inherited Members
Public Types inherited from mfem::Operator
enum	DiagonalPolicy { DIAG_ZERO , DIAG_ONE , DIAG_KEEP }
	Defines operator diagonal policy upon elimination of rows and/or columns. More...

enum	Type { ANY_TYPE , MFEM_SPARSEMAT , Hypre_ParCSR , PETSC_MATAIJ , PETSC_MATIS , PETSC_MATSHELL , PETSC_MATNEST , PETSC_MATHYPRE , PETSC_MATGENERIC , Complex_Operator , MFEM_ComplexSparseMat , Complex_Hypre_ParCSR , Complex_DenseMat , MFEM_Block_Matrix , MFEM_Block_Operator }
	Enumeration defining IDs for some classes derived from Operator. More...

Protected Member Functions inherited from mfem::Operator
void	FormConstrainedSystemOperator (const Array< int > &ess_tdof_list, ConstrainedOperator *&Aout)
	see FormSystemOperator()

void	FormRectangularConstrainedSystemOperator (const Array< int > &trial_tdof_list, const Array< int > &test_tdof_list, RectangularConstrainedOperator *&Aout)
	see FormRectangularSystemOperator()

Operator *	SetupRAP (const Operator Pi, const Operator Po)
	Returns RAP Operator of this, using input/output Prolongation matrices Pi corresponds to "P", Po corresponds to "Rt".

Protected Attributes inherited from mfem::Operator
int	height
	Dimension of the output / number of rows in the matrix.

int	width
	Dimension of the input / number of columns in the matrix.

Detailed Description

A class to handle Block diagonal preconditioners in a matrix-free implementation.

Usage:

Use the constructors to define the block structure
Use SetDiagonalBlock to fill the BlockDiagonalPreconditioner
Use the method Mult and MultTranspose to apply the operator to a vector.

If a block is not set, it is assumed to be an identity block.

Definition at line 148 of file blockoperator.hpp.

Constructor & Destructor Documentation

◆ BlockDiagonalPreconditioner()

mfem::BlockDiagonalPreconditioner::BlockDiagonalPreconditioner ( const Array< int > & offsets )

Constructor that specifies the block structure.

Definition at line 144 of file blockoperator.cpp.

◆ ~BlockDiagonalPreconditioner()

mfem::BlockDiagonalPreconditioner::~BlockDiagonalPreconditioner ( )

Definition at line 230 of file blockoperator.cpp.

Member Function Documentation

◆ GetDiagonalBlock() [1/2]

Operator & mfem::BlockDiagonalPreconditioner::GetDiagonalBlock ( int iblock )

inline

Return a reference to block i,i.

Definition at line 166 of file blockoperator.hpp.

◆ GetDiagonalBlock() [2/2]

const Operator & mfem::BlockDiagonalPreconditioner::GetDiagonalBlock ( int iblock ) const

inline

Return a reference to block i,i (const version).

Definition at line 170 of file blockoperator.hpp.

◆ Mult()

void mfem::BlockDiagonalPreconditioner::Mult	(	const Vector &	x,
		Vector &	y ) const

virtual

Operator application.

Implements mfem::Operator.

Definition at line 170 of file blockoperator.cpp.

◆ MultTranspose()

void mfem::BlockDiagonalPreconditioner::MultTranspose	(	const Vector &	x,
		Vector &	y ) const

virtual

Action of the transpose operator.

Reimplemented from mfem::Operator.

Definition at line 200 of file blockoperator.cpp.

◆ NumBlocks()

int mfem::BlockDiagonalPreconditioner::NumBlocks ( ) const

inline

Return the number of blocks.

Definition at line 163 of file blockoperator.hpp.

◆ Offsets() [1/2]

Array< int > & mfem::BlockDiagonalPreconditioner::Offsets ( )

inline

Return the offsets for block starts.

Definition at line 174 of file blockoperator.hpp.

◆ Offsets() [2/2]

const Array< int > & mfem::BlockDiagonalPreconditioner::Offsets ( ) const

inline

Read only access to the offsets for block starts.

Definition at line 177 of file blockoperator.hpp.

◆ SetDiagonalBlock()

void mfem::BlockDiagonalPreconditioner::SetDiagonalBlock	(	int	iblock,
		Operator *	op )

Add a square block op in the block-entry (iblock, iblock).

iblock: The block will be inserted in location (iblock, iblock). op: the Operator to be inserted.

Definition at line 156 of file blockoperator.cpp.

◆ SetOperator()

virtual void mfem::BlockDiagonalPreconditioner::SetOperator ( const Operator & op )

inlinevirtual

This method is present since required by the abstract base class Solver.

Implements mfem::Solver.

Definition at line 160 of file blockoperator.hpp.

Member Data Documentation

◆ owns_blocks

int mfem::BlockDiagonalPreconditioner::owns_blocks

Controls the ownership of the blocks: if nonzero, BlockDiagonalPreconditioner will delete all blocks that are set (non-NULL); the default value is zero.

Definition at line 190 of file blockoperator.hpp.

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

linalg/blockoperator.hpp
linalg/blockoperator.cpp

Public Member Functions

Public Attributes

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

◆ BlockDiagonalPreconditioner()

◆ ~BlockDiagonalPreconditioner()

Member Function Documentation

◆ GetDiagonalBlock() [1/2]

◆ GetDiagonalBlock() [2/2]

◆ Mult()

◆ MultTranspose()

◆ NumBlocks()

◆ Offsets() [1/2]

◆ Offsets() [2/2]

◆ SetDiagonalBlock()

◆ SetOperator()

Member Data Documentation

◆ owns_blocks