MFEM  v4.5.1 Finite element discretization library
mfem::OperatorJacobiSmoother Class Reference

Jacobi smoothing for a given bilinear form (no matrix necessary). More...

#include <solvers.hpp>

Inheritance diagram for mfem::OperatorJacobiSmoother:
[legend]
Collaboration diagram for mfem::OperatorJacobiSmoother:
[legend]

## Public Member Functions

OperatorJacobiSmoother (const double damping=1.0)
Default constructor: the diagonal will be computed by subsequent calls to SetOperator() using the Operator method AssembleDiagonal. More...

OperatorJacobiSmoother (const BilinearForm &a, const Array< int > &ess_tdof_list, const double damping=1.0)

OperatorJacobiSmoother (const Vector &d, const Array< int > &ess_tdof_list, const double damping=1.0)

~OperatorJacobiSmoother ()

void SetPositiveDiagonal (bool pos_diag=true)
Replace diagonal entries with their absolute values. More...

void Mult (const Vector &x, Vector &y) const
Operator application: y=A(x). More...

void MultTranspose (const Vector &x, Vector &y) const
Action of the transpose operator: y=A^t(x). The default behavior in class Operator is to generate an error. More...

void SetOperator (const Operator &op)
Recompute the diagonal using the method AssembleDiagonal of the given new Operator, op. More...

void Setup (const Vector &diag)

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
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. More...

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 OperatorGetGradient (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 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. More...

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

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

virtual const OperatorGetOutputProlongation () const
Prolongation operator from linear algebra (linear system) vectors, to output vectors for the operator. NULL means identity. More...

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

virtual const OperatorGetOutputRestriction () const
Restriction operator from output 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...

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. 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() or Operator::FormRectangularLinearSystem(). More...

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

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). More...

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

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

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

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

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

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...

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

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

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

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". 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

Jacobi smoothing for a given bilinear form (no matrix necessary).

Useful with tensorized, partially assembled operators. Can also be defined by given diagonal vector. This is basic Jacobi iteration; for tolerances, iteration control, etc. wrap with SLISolver.

Definition at line 274 of file solvers.hpp.

## Constructor & Destructor Documentation

 mfem::OperatorJacobiSmoother::OperatorJacobiSmoother ( const double damping = 1.0 )

Default constructor: the diagonal will be computed by subsequent calls to SetOperator() using the Operator method AssembleDiagonal.

In this case the array of essential tdofs will be empty.

Definition at line 200 of file solvers.cpp.

 mfem::OperatorJacobiSmoother::OperatorJacobiSmoother ( const BilinearForm & a, const Array< int > & ess_tdof_list, const double damping = 1.0 )

Setup a Jacobi smoother with the diagonal of a obtained by calling a.AssembleDiagonal(). It is assumed that the underlying operator acts as the identity on entries in ess_tdof_list, corresponding to (assembled) DIAG_ONE policy or ConstrainedOperator in the matrix-free setting.

Note
For objects created with this constructor, calling SetOperator() will only set the internal Operator pointer to the given new Operator without any other changes to the object. This is done to preserve the original behavior of this class.

Definition at line 207 of file solvers.cpp.

 mfem::OperatorJacobiSmoother::OperatorJacobiSmoother ( const Vector & d, const Array< int > & ess_tdof_list, const double damping = 1.0 )

Application is by the inverse of the given vector. It is assumed that the underlying operator acts as the identity on entries in ess_tdof_list, corresponding to (assembled) DIAG_ONE policy or ConstrainedOperator in the matrix-free setting.

Note
For objects created with this constructor, calling SetOperator() will only set the internal Operator pointer to the given new Operator without any other changes to the object. This is done to preserve the original behavior of this class.

Definition at line 226 of file solvers.cpp.

 mfem::OperatorJacobiSmoother::~OperatorJacobiSmoother ( )
inline

Definition at line 308 of file solvers.hpp.

## Member Function Documentation

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

Operator application: y=A(x).

Implements mfem::Operator.

Definition at line 300 of file solvers.cpp.

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

Action of the transpose operator: y=A^t(x). The default behavior in class Operator is to generate an error.

Reimplemented from mfem::Operator.

Definition at line 314 of file solvers.hpp.

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

Recompute the diagonal using the method AssembleDiagonal of the given new Operator, op.

Note that (Par)BilinearForm operators are treated similar to the way they are treated in the constructor that takes a BilinearForm parameter. Specifically, this means that the OperatorJacobiSmoother will work with true-dof vectors even though the size of the BilinearForm may be different.

When the new Operator, op, is not a (Par)BilinearForm, any previously set array of essential true-dofs will be thrown away because in this case any essential b.c. will be handled by the AssembleDiagonal method.

Implements mfem::Solver.

Definition at line 241 of file solvers.cpp.

 void mfem::OperatorJacobiSmoother::SetPositiveDiagonal ( bool pos_diag = true )
inline

Replace diagonal entries with their absolute values.

Definition at line 311 of file solvers.hpp.

 void mfem::OperatorJacobiSmoother::Setup ( const Vector & diag )

Definition at line 277 of file solvers.cpp.

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