MFEM v4.7.0
Finite element discretization library
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mfem::BlockOperator Class Reference

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

#include <blockoperator.hpp>

Inheritance diagram for mfem::BlockOperator:
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Collaboration diagram for mfem::BlockOperator:
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Public Member Functions

 BlockOperator (const Array< int > &offsets)
 
 BlockOperator (const Array< int > &row_offsets, const Array< int > &col_offsets)
 Constructor for general BlockOperators.
 
BlockOperatoroperator= (const BlockOperator &)=delete
 Copy assignment is not supported.
 
BlockOperatoroperator= (BlockOperator &&)=delete
 Move assignment is not supported.
 
void SetDiagonalBlock (int iblock, Operator *op, real_t c=1.0)
 Add block op in the block-entry (iblock, iblock).
 
void SetBlock (int iRow, int iCol, Operator *op, real_t c=1.0)
 Add a block op in the block-entry (iblock, jblock).
 
int NumRowBlocks () const
 Return the number of row blocks.
 
int NumColBlocks () const
 Return the number of column blocks.
 
int IsZeroBlock (int i, int j) const
 Check if block (i,j) is a zero block.
 
OperatorGetBlock (int i, int j)
 Return a reference to block i,j.
 
const OperatorGetBlock (int i, int j) const
 Return a reference to block i,j (const version)
 
real_t GetBlockCoef (int i, int j) const
 Return the coefficient for block i,j.
 
void SetBlockCoef (int i, int j, real_t c)
 Set the coefficient for block i,j.
 
Array< int > & RowOffsets ()
 Return the row offsets for block starts.
 
const Array< int > & RowOffsets () const
 Read only access to the row offsets for block starts.
 
Array< int > & ColOffsets ()
 Return the columns offsets for block starts.
 
const Array< int > & ColOffsets () const
 Read only access to the columns 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.
 
 ~BlockOperator ()
 
virtual Type GetType () const
 
- 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 OperatorGetGradient (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 OperatorGetProlongation () const
 Prolongation operator from linear algebra (linear system) vectors, to input vectors for the operator. NULL means identity.
 
virtual const OperatorGetRestriction () const
 Restriction operator from input vectors for the operator to linear algebra (linear system) vectors. NULL means identity.
 
virtual const OperatorGetOutputProlongation () const
 Prolongation operator from linear algebra (linear system) vectors, to output vectors for the operator. NULL means identity.
 
virtual const OperatorGetOutputRestrictionTranspose () const
 Transpose of GetOutputRestriction, directly available in this form to facilitate matrix-free RAP-type operators.
 
virtual const OperatorGetOutputRestriction () 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
 

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()
 
OperatorSetupRAP (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 systems in a matrix-free implementation.

Usage:

  • Use one of the constructors to define the block structure.
  • Use SetDiagonalBlock or SetBlock to fill the BlockOperator
  • Use the method Mult and MultTranspose to apply the operator to a vector.

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

Definition at line 34 of file blockoperator.hpp.

Constructor & Destructor Documentation

◆ BlockOperator() [1/2]

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

Constructor for BlockOperators with the same block-structure for rows and columns. offsets: offsets that mark the start of each row/column block (size nRowBlocks+1).

Definition at line 21 of file blockoperator.cpp.

◆ BlockOperator() [2/2]

mfem::BlockOperator::BlockOperator ( const Array< int > & row_offsets,
const Array< int > & col_offsets )

Constructor for general BlockOperators.

row_offsets: offsets that mark the start of each row block (size nRowBlocks+1). col_offsets: offsets that mark the start of each column block (size nColBlocks+1).

Definition at line 34 of file blockoperator.cpp.

◆ ~BlockOperator()

mfem::BlockOperator::~BlockOperator ( )

Definition at line 129 of file blockoperator.cpp.

Member Function Documentation

◆ ColOffsets() [1/2]

Array< int > & mfem::BlockOperator::ColOffsets ( )
inline

Return the columns offsets for block starts.

Definition at line 98 of file blockoperator.hpp.

◆ ColOffsets() [2/2]

const Array< int > & mfem::BlockOperator::ColOffsets ( ) const
inline

Read only access to the columns offsets for block starts.

Definition at line 100 of file blockoperator.hpp.

◆ GetBlock() [1/2]

Operator & mfem::BlockOperator::GetBlock ( int i,
int j )
inline

Return a reference to block i,j.

Definition at line 81 of file blockoperator.hpp.

◆ GetBlock() [2/2]

const Operator & mfem::BlockOperator::GetBlock ( int i,
int j ) const
inline

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

Definition at line 84 of file blockoperator.hpp.

◆ GetBlockCoef()

real_t mfem::BlockOperator::GetBlockCoef ( int i,
int j ) const
inline

Return the coefficient for block i,j.

Definition at line 87 of file blockoperator.hpp.

◆ GetType()

virtual Type mfem::BlockOperator::GetType ( ) const
inlinevirtual

Definition at line 114 of file blockoperator.hpp.

◆ IsZeroBlock()

int mfem::BlockOperator::IsZeroBlock ( int i,
int j ) const
inline

Check if block (i,j) is a zero block.

Definition at line 79 of file blockoperator.hpp.

◆ Mult()

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

Operator application.

Implements mfem::Operator.

Definition at line 68 of file blockoperator.cpp.

◆ MultTranspose()

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

Action of the transpose operator.

Reimplemented from mfem::Operator.

Definition at line 99 of file blockoperator.cpp.

◆ NumColBlocks()

int mfem::BlockOperator::NumColBlocks ( ) const
inline

Return the number of column blocks.

Definition at line 76 of file blockoperator.hpp.

◆ NumRowBlocks()

int mfem::BlockOperator::NumRowBlocks ( ) const
inline

Return the number of row blocks.

Definition at line 74 of file blockoperator.hpp.

◆ operator=() [1/2]

BlockOperator & mfem::BlockOperator::operator= ( BlockOperator && )
delete

Move assignment is not supported.

◆ operator=() [2/2]

BlockOperator & mfem::BlockOperator::operator= ( const BlockOperator & )
delete

Copy assignment is not supported.

◆ RowOffsets() [1/2]

Array< int > & mfem::BlockOperator::RowOffsets ( )
inline

Return the row offsets for block starts.

Definition at line 94 of file blockoperator.hpp.

◆ RowOffsets() [2/2]

const Array< int > & mfem::BlockOperator::RowOffsets ( ) const
inline

Read only access to the row offsets for block starts.

Definition at line 96 of file blockoperator.hpp.

◆ SetBlock()

void mfem::BlockOperator::SetBlock ( int iRow,
int iCol,
Operator * op,
real_t c = 1.0 )

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

irow, icol: The block will be inserted in location (irow, icol). op: the Operator to be inserted. c: optional scalar multiple for this block.

Definition at line 53 of file blockoperator.cpp.

◆ SetBlockCoef()

void mfem::BlockOperator::SetBlockCoef ( int i,
int j,
real_t c )
inline

Set the coefficient for block i,j.

Definition at line 90 of file blockoperator.hpp.

◆ SetDiagonalBlock()

void mfem::BlockOperator::SetDiagonalBlock ( int iblock,
Operator * op,
real_t c = 1.0 )

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

iblock: The block will be inserted in location (iblock, iblock). op: the Operator to be inserted. c: optional scalar multiple for this block.

Definition at line 48 of file blockoperator.cpp.

Member Data Documentation

◆ owns_blocks

int mfem::BlockOperator::owns_blocks

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

Definition at line 112 of file blockoperator.hpp.


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