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

Abstract base class for iterative solver. More...

#include <solvers.hpp>

Inheritance diagram for mfem::IterativeSolver:
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Collaboration diagram for mfem::IterativeSolver:
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Classes

struct  PrintLevel
 Settings for the output behavior of the IterativeSolver. More...
 

Public Member Functions

 IterativeSolver ()
 
 IterativeSolver (MPI_Comm comm_)
 
virtual void SetPreconditioner (Solver &pr)
 This should be called before SetOperator. More...
 
virtual void SetOperator (const Operator &op) override
 Also calls SetOperator for the preconditioner if there is one. More...
 
void SetMonitor (IterativeSolverMonitor &m)
 Set the iterative solver monitor. More...
 
MPI_Comm GetComm () const
 Return the associated MPI communicator, or MPI_COMM_NULL if no communicator is set. More...
 
Convergence

Termination criteria for the iterative solvers.

While the convergence criterion is solver specific, most of the provided iterative solvers use one of the following criteria

\( ||r||_X \leq tol_{rel}||r_0||_X \),

\( ||r||_X \leq tol_{abs} \),

\( ||r||_X \leq \max\{ tol_{abs}, tol_{rel} ||r_0||_X \} \),

where X denotes the space in which the norm is measured. The choice of X depends on the specific iterative solver.

void SetRelTol (double rtol)
 
void SetAbsTol (double atol)
 
void SetMaxIter (int max_it)
 
Reporting

These options control the internal reporting behavior into mfem::out and mfem::err of the iterative solvers.

virtual void SetPrintLevel (int print_lvl)
 Legacy method to set the level of verbosity of the solver output. More...
 
virtual void SetPrintLevel (PrintLevel)
 Set the level of verbosity of the solver output. More...
 
Solver statistics
int GetNumIterations () const
 
bool GetConverged () const
 
double GetFinalNorm () const
 
- 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 Mult (const Vector &x, Vector &y) const =0
 Operator application: y=A(x). 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 Member Functions

double Dot (const Vector &x, const Vector &y) const
 
double Norm (const Vector &x) const
 
void Monitor (int it, double norm, const Vector &r, const Vector &x, bool final=false) const
 
- 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

const Operatoroper
 
Solverprec
 
IterativeSolverMonitormonitor = nullptr
 
Convergence (protected attributes)
int max_iter
 Limit for the number of iterations the solver is allowed to do. More...
 
double rel_tol
 Relative tolerance. More...
 
double abs_tol
 Absolute tolerance. More...
 
Solver statistics (protected attributes)
int final_iter
 
bool converged
 
double final_norm
 
- 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...
 

Reporting (protected attributes and member functions)

int print_level = -1
 (DEPRECATED) Legacy print level definition, which is left for compatibility with custom iterative solvers. More...
 
PrintLevel print_options
 Output behavior for the iterative solver. More...
 
PrintLevel FromLegacyPrintLevel (int)
 Convert a legacy print level integer to a PrintLevel object. More...
 
static int GuessLegacyPrintLevel (PrintLevel)
 Use some heuristics to guess a legacy print level corresponding to the given PrintLevel. More...
 

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

Detailed Description

Abstract base class for iterative solver.

Definition at line 66 of file solvers.hpp.

Constructor & Destructor Documentation

mfem::IterativeSolver::IterativeSolver ( )

Definition at line 28 of file solvers.cpp.

mfem::IterativeSolver::IterativeSolver ( MPI_Comm  comm_)

Definition at line 42 of file solvers.cpp.

Member Function Documentation

double mfem::IterativeSolver::Dot ( const Vector x,
const Vector y 
) const
protected

Definition at line 55 of file solvers.cpp.

IterativeSolver::PrintLevel mfem::IterativeSolver::FromLegacyPrintLevel ( int  print_level_)
protected

Convert a legacy print level integer to a PrintLevel object.

Definition at line 114 of file solvers.cpp.

MPI_Comm mfem::IterativeSolver::GetComm ( ) const
inline

Return the associated MPI communicator, or MPI_COMM_NULL if no communicator is set.

Definition at line 264 of file solvers.hpp.

bool mfem::IterativeSolver::GetConverged ( ) const
inline

Definition at line 247 of file solvers.hpp.

double mfem::IterativeSolver::GetFinalNorm ( ) const
inline

Definition at line 248 of file solvers.hpp.

int mfem::IterativeSolver::GetNumIterations ( ) const
inline

Definition at line 246 of file solvers.hpp.

int mfem::IterativeSolver::GuessLegacyPrintLevel ( PrintLevel  print_options_)
staticprotected

Use some heuristics to guess a legacy print level corresponding to the given PrintLevel.

Definition at line 149 of file solvers.cpp.

void mfem::IterativeSolver::Monitor ( int  it,
double  norm,
const Vector r,
const Vector x,
bool  final = false 
) const
protected

Definition at line 190 of file solvers.cpp.

double mfem::IterativeSolver::Norm ( const Vector x) const
inlineprotected

Definition at line 171 of file solvers.hpp.

void mfem::IterativeSolver::SetAbsTol ( double  atol)
inline

Definition at line 199 of file solvers.hpp.

void mfem::IterativeSolver::SetMaxIter ( int  max_it)
inline

Definition at line 200 of file solvers.hpp.

void mfem::IterativeSolver::SetMonitor ( IterativeSolverMonitor m)
inline

Set the iterative solver monitor.

Definition at line 258 of file solvers.hpp.

void mfem::IterativeSolver::SetOperator ( const Operator op)
overridevirtual
void mfem::IterativeSolver::SetPreconditioner ( Solver pr)
virtual
void mfem::IterativeSolver::SetPrintLevel ( int  print_lvl)
virtual

Legacy method to set the level of verbosity of the solver output.

This is the old way to control what information will be printed to mfem::out and mfem::err. The behavior for the print level for all iterative solvers is:

  • -1: Suppress all outputs.
  • 0: Print information about all detected issues (e.g. no convergence).
  • 1: Same as level 0, but with detailed information about each iteration.
  • 2: Print detected issues and a summary when the solver terminates.
  • 3: Same as 2, but print also the first and last iterations.
  • >3: Custom print options which are dependent on the specific solver.

In parallel, only rank 0 produces output.

Note
It is recommended to use SetPrintLevel(PrintLevel) instead.
Some derived classes, like KINSolver, redefine this method and use their own set of print level constants.

Reimplemented in mfem::KINSolver.

Definition at line 71 of file solvers.cpp.

void mfem::IterativeSolver::SetPrintLevel ( PrintLevel  options)
virtual

Set the level of verbosity of the solver output.

In parallel, only rank 0 produces outputs. Errors are output to mfem::err and all other information to mfem::out.

Note
Not all subclasses of IterativeSolver support all possible options.
Some derived classes, like KINSolver, disable this method in favor of SetPrintLevel(int).
See Also
PrintLevel for possible options.

Reimplemented in mfem::KINSolver.

Definition at line 92 of file solvers.cpp.

void mfem::IterativeSolver::SetRelTol ( double  rtol)
inline

Definition at line 198 of file solvers.hpp.

Member Data Documentation

double mfem::IterativeSolver::abs_tol
protected

Absolute tolerance.

Definition at line 157 of file solvers.hpp.

bool mfem::IterativeSolver::converged
mutableprotected

Definition at line 165 of file solvers.hpp.

int mfem::IterativeSolver::final_iter
mutableprotected

Definition at line 164 of file solvers.hpp.

double mfem::IterativeSolver::final_norm
mutableprotected

Definition at line 166 of file solvers.hpp.

int mfem::IterativeSolver::max_iter
protected

Limit for the number of iterations the solver is allowed to do.

Definition at line 151 of file solvers.hpp.

IterativeSolverMonitor* mfem::IterativeSolver::monitor = nullptr
protected

Definition at line 122 of file solvers.hpp.

const Operator* mfem::IterativeSolver::oper
protected

Definition at line 120 of file solvers.hpp.

Solver* mfem::IterativeSolver::prec
protected

Definition at line 121 of file solvers.hpp.

int mfem::IterativeSolver::print_level = -1
protected

(DEPRECATED) Legacy print level definition, which is left for compatibility with custom iterative solvers.

Deprecated:
print_options should be used instead.

Definition at line 130 of file solvers.hpp.

PrintLevel mfem::IterativeSolver::print_options
protected

Output behavior for the iterative solver.

This primarily controls the output behavior of the iterative solvers provided by this library. This member must be synchronized with print_level to ensure compatibility with custom iterative solvers.

Definition at line 137 of file solvers.hpp.

double mfem::IterativeSolver::rel_tol
protected

Relative tolerance.

Definition at line 154 of file solvers.hpp.


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