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

Multigrid solver class. More...

#include <multigrid.hpp>

Inheritance diagram for mfem::Multigrid:
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Collaboration diagram for mfem::Multigrid:
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Public Types

enum  CycleType { CycleType::VCYCLE, CycleType::WCYCLE }
 
- 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 Member Functions

 Multigrid ()
 Constructs an empty multigrid hierarchy. More...
 
 Multigrid (const Array< Operator * > &operators_, const Array< Solver * > &smoothers_, const Array< Operator * > &prolongations_, const Array< bool > &ownedOperators_, const Array< bool > &ownedSmoothers_, const Array< bool > &ownedProlongations_)
 Constructs a multigrid hierarchy from the given inputs. More...
 
virtual ~Multigrid ()
 Destructor. More...
 
void AddLevel (Operator *opr, Solver *smoother, bool ownOperator, bool ownSmoother)
 Adds a level to the multigrid operator hierarchy. More...
 
int NumLevels () const
 Returns the number of levels. More...
 
int GetFinestLevelIndex () const
 Returns the index of the finest level. More...
 
const OperatorGetOperatorAtLevel (int level) const
 Returns operator at given level. More...
 
OperatorGetOperatorAtLevel (int level)
 Returns operator at given level. More...
 
const OperatorGetOperatorAtFinestLevel () const
 Returns operator at finest level. More...
 
OperatorGetOperatorAtFinestLevel ()
 Returns operator at finest level. More...
 
SolverGetSmootherAtLevel (int level) const
 Returns smoother at given level. More...
 
SolverGetSmootherAtLevel (int level)
 Returns smoother at given level. More...
 
void SetCycleType (CycleType cycleType_, int preSmoothingSteps_, int postSmoothingSteps_)
 Set cycle type and number of pre- and post-smoothing steps used by Mult. More...
 
virtual void Mult (const Vector &x, Vector &y) const override
 Application of the multigrid as a preconditioner. More...
 
virtual void SetOperator (const Operator &op) override
 Not supported for multigrid. More...
 
- 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 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...
 
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...
 

Protected Attributes

Array< Operator * > operators
 
Array< Solver * > smoothers
 
Array< Operator * > prolongations
 
Array< bool > ownedOperators
 
Array< bool > ownedSmoothers
 
Array< bool > ownedProlongations
 
CycleType cycleType
 
int preSmoothingSteps
 
int postSmoothingSteps
 
Array< Vector * > X
 
Array< Vector * > Y
 
Array< Vector * > R
 
Array< Vector * > Z
 
- 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...
 

Additional Inherited Members

- 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...
 

Detailed Description

Multigrid solver class.

Definition at line 25 of file multigrid.hpp.

Member Enumeration Documentation

Enumerator
VCYCLE 
WCYCLE 

Definition at line 28 of file multigrid.hpp.

Constructor & Destructor Documentation

mfem::Multigrid::Multigrid ( )

Constructs an empty multigrid hierarchy.

Definition at line 17 of file multigrid.cpp.

mfem::Multigrid::Multigrid ( const Array< Operator * > &  operators_,
const Array< Solver * > &  smoothers_,
const Array< Operator * > &  prolongations_,
const Array< bool > &  ownedOperators_,
const Array< bool > &  ownedSmoothers_,
const Array< bool > &  ownedProlongations_ 
)

Constructs a multigrid hierarchy from the given inputs.

Inputs include operators and smoothers on all levels, prolongation operators that go from coarser to finer levels, and ownership of the given operators, smoothers, and prolongations.

Definition at line 21 of file multigrid.cpp.

mfem::Multigrid::~Multigrid ( )
virtual

Destructor.

Definition at line 51 of file multigrid.cpp.

Member Function Documentation

void mfem::Multigrid::AddLevel ( Operator opr,
Solver smoother,
bool  ownOperator,
bool  ownSmoother 
)

Adds a level to the multigrid operator hierarchy.

The ownership of the operators and solvers/smoothers may be transferred to the Multigrid by setting the according boolean variables.

Definition at line 86 of file multigrid.cpp.

int mfem::Multigrid::GetFinestLevelIndex ( ) const

Returns the index of the finest level.

Definition at line 108 of file multigrid.cpp.

const Operator * mfem::Multigrid::GetOperatorAtFinestLevel ( ) const

Returns operator at finest level.

Definition at line 120 of file multigrid.cpp.

Operator * mfem::Multigrid::GetOperatorAtFinestLevel ( )

Returns operator at finest level.

Definition at line 125 of file multigrid.cpp.

const Operator * mfem::Multigrid::GetOperatorAtLevel ( int  level) const

Returns operator at given level.

Definition at line 110 of file multigrid.cpp.

Operator * mfem::Multigrid::GetOperatorAtLevel ( int  level)

Returns operator at given level.

Definition at line 115 of file multigrid.cpp.

Solver * mfem::Multigrid::GetSmootherAtLevel ( int  level) const

Returns smoother at given level.

Definition at line 130 of file multigrid.cpp.

Solver * mfem::Multigrid::GetSmootherAtLevel ( int  level)

Returns smoother at given level.

Definition at line 135 of file multigrid.cpp.

void mfem::Multigrid::Mult ( const Vector x,
Vector y 
) const
overridevirtual

Application of the multigrid as a preconditioner.

Implements mfem::Operator.

Definition at line 148 of file multigrid.cpp.

int mfem::Multigrid::NumLevels ( ) const

Returns the number of levels.

Definition at line 106 of file multigrid.cpp.

void mfem::Multigrid::SetCycleType ( CycleType  cycleType_,
int  preSmoothingSteps_,
int  postSmoothingSteps_ 
)

Set cycle type and number of pre- and post-smoothing steps used by Mult.

Definition at line 140 of file multigrid.cpp.

void mfem::Multigrid::SetOperator ( const Operator op)
overridevirtual

Not supported for multigrid.

Implements mfem::Solver.

Reimplemented in mfem::ceed::AlgebraicMultigrid.

Definition at line 157 of file multigrid.cpp.

Member Data Documentation

CycleType mfem::Multigrid::cycleType
protected

Definition at line 43 of file multigrid.hpp.

Array<Operator*> mfem::Multigrid::operators
protected

Definition at line 35 of file multigrid.hpp.

Array<bool> mfem::Multigrid::ownedOperators
protected

Definition at line 39 of file multigrid.hpp.

Array<bool> mfem::Multigrid::ownedProlongations
protected

Definition at line 41 of file multigrid.hpp.

Array<bool> mfem::Multigrid::ownedSmoothers
protected

Definition at line 40 of file multigrid.hpp.

int mfem::Multigrid::postSmoothingSteps
protected

Definition at line 45 of file multigrid.hpp.

int mfem::Multigrid::preSmoothingSteps
protected

Definition at line 44 of file multigrid.hpp.

Array<Operator*> mfem::Multigrid::prolongations
protected

Definition at line 37 of file multigrid.hpp.

Array<Vector*> mfem::Multigrid::R
mutableprotected

Definition at line 49 of file multigrid.hpp.

Array<Solver*> mfem::Multigrid::smoothers
protected

Definition at line 36 of file multigrid.hpp.

Array<Vector*> mfem::Multigrid::X
mutableprotected

Definition at line 47 of file multigrid.hpp.

Array<Vector*> mfem::Multigrid::Y
mutableprotected

Definition at line 48 of file multigrid.hpp.

Array<Vector*> mfem::Multigrid::Z
mutableprotected

Definition at line 50 of file multigrid.hpp.


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