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

#include <blockoperator.hpp>

Inheritance diagram for mfem::BlockLowerTriangularPreconditioner:

Collaboration diagram for mfem::BlockLowerTriangularPreconditioner:

Public Member Functions
	BlockLowerTriangularPreconditioner (const Array< int > &offsets)

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

void	SetBlock (int iRow, int iCol, Operator *op)
	Add a block op in the block-entry (iblock, jblock). More...

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

int	NumBlocks () const
	Return the number of blocks. More...

Operator &	GetBlock (int iblock, int jblock)
	Return a reference to block i,j. More...

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

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

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

	~BlockLowerTriangularPreconditioner ()

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

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

Public Member Functions inherited from mfem::Operator
	Operator (int s=0)
	Construct a square Operator with given size s (default 0). More...

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

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

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

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

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

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

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. More...

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

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

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. More...

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(). More...

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

virtual	~Operator ()
	Virtual destructor. More...

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

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. More...

Additional Inherited Members
Public Types inherited from mfem::Operator
enum	Type { ANY_TYPE, MFEM_SPARSEMAT, Hypre_ParCSR, PETSC_MATAIJ, PETSC_MATIS, PETSC_MATSHELL, PETSC_MATNEST, PETSC_MATHYPRE, PETSC_MATGENERIC }
	Enumeration defining IDs for some classes derived from Operator. More...

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

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

Detailed Description

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

Usage:

Use the constructors to define the block structure
Use SetBlock() to fill the BlockOperator
Diagonal blocks of the preconditioner should approximate the inverses of the diagonal block of the matrix
Off-diagonal blocks of the preconditioner should match/approximate those of the original matrix
Use the method Mult() and MultTranspose() to apply the operator to a vector.

If a diagonal block is not set, it is assumed to be an identity block, if an off-diagonal block is not set, it is assumed to be a zero block.

Definition at line 203 of file blockoperator.hpp.

Constructor & Destructor Documentation

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

Constructor for BlockLowerTriangularPreconditioners with the same block-structure for rows and columns.

Parameters

offsets Offsets that mark the start of each row/column block (size nBlocks+1).

Note: BlockLowerTriangularPreconditioner will not own/copy the data contained in offsets.

Definition at line 210 of file blockoperator.cpp.

mfem::BlockLowerTriangularPreconditioner::~BlockLowerTriangularPreconditioner ( )

Definition at line 315 of file blockoperator.cpp.

Member Function Documentation

Operator& mfem::BlockLowerTriangularPreconditioner::GetBlock	(	int	iblock,
		int	jblock
	)

inline

Return a reference to block i,j.

Definition at line 236 of file blockoperator.hpp.

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

virtual

Operator application.

Implements mfem::Operator.

Definition at line 244 of file blockoperator.cpp.

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

virtual

Action of the transpose operator.

Reimplemented from mfem::Operator.

Definition at line 280 of file blockoperator.cpp.

int mfem::BlockLowerTriangularPreconditioner::NumBlocks ( ) const

inline

Return the number of blocks.

Definition at line 233 of file blockoperator.hpp.

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

inline

Return the offsets for block starts.

Definition at line 240 of file blockoperator.hpp.

void mfem::BlockLowerTriangularPreconditioner::SetBlock	(	int	iRow,
		int	iCol,
		Operator *	op
	)

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

Parameters

iRow,iCol	The block will be inserted in location (iRow, iCol).
op	The Operator to be inserted.

Definition at line 232 of file blockoperator.cpp.

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

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

Parameters

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

Definition at line 222 of file blockoperator.cpp.

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

inlinevirtual

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

Implements mfem::Solver.

Definition at line 230 of file blockoperator.hpp.

Member Data Documentation

int mfem::BlockLowerTriangularPreconditioner::owns_blocks

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

Definition at line 253 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

Member Function Documentation

Member Data Documentation