Ifpack Class Reference

Ifpack: a function class to define Ifpack preconditioners. More...

#include <Ifpack.h>

List of all members.

Public Types

enum parameter {
  absolute_threshold, relative_threshold, drop_tolerance, fill_tolerance,
  relax_value, level_fill, level_overlap, num_steps,
  use_reciprocal, overlap_mode
}

enum EPrecType {
  POINT_RELAXATION, POINT_RELAXATION_STAND_ALONE, BLOCK_RELAXATION, BLOCK_RELAXATION_STAND_ALONE,
  BLOCK_RELAXATION_STAND_ALONE_ILU, BLOCK_RELAXATION_STAND_ALONE_AMESOS, BLOCK_RELAXATION_AMESOS, AMESOS,
  AMESOS_STAND_ALONE, IC, IC_STAND_ALONE, ICT,
  ICT_STAND_ALONE, ILU, ILU_STAND_ALONE, ILUT,
  ILUT_STAND_ALONE, CHEBYSHEV
}

Enum for the type of preconditioner.

Public Member Functions

Ifpack_Preconditioner * Create (const string PrecType, Epetra_RowMatrix *Matrix, const int overlap=0)

Creates an instance of Ifpack_Preconditioner given the string name of the preconditioner type (can fail with bad input).

int SetParameters (int argc, char *argv[], Teuchos::ParameterList &List, string &PrecType, int &Overlap)

Sets the options in List from the command line.

Static Public Member Functions

const char * toString (const EPrecType precType)

Function that gives the string name for preconditioner given its enumerication value.

Ifpack_Preconditioner * Create (EPrecType PrecType, Epetra_RowMatrix *Matrix, const int overlap=0)

Creates an instance of Ifpack_Preconditioner given the enum value of the preconditioner type (can not fail, no bad input possible).

Static Public Attributes

const int numPrecTypes

const EPrecType precTypeValues [numPrecTypes]

List of the preconditioner types as enum values .

const char * precTypeNames [numPrecTypes]

List of preconditioner types as string values.

const bool supportsUnsymmetric [numPrecTypes]

List of bools that determines if the precondtioner type supports unsymmetric matrices.

Detailed Description

Ifpack: a function class to define Ifpack preconditioners.

Class Ifpack is a function class, that contains just one method: Create(). Using Create(), users can easily define a variety of IFPACK preconditioners.

Create requires 3 arguments:

a string, indicating the preconditioner to be built;
a pointer to an Epetra_RowMatrix, representing the matrix to be used to define the preconditioner;
an interger (defaulted to 0), that specifies the amount of overlap among the processes.

The first argument can assume the following values:

"point relaxation" : returns an instance of Ifpack_AdditiveSchwarz<Ifpack_PointRelaxation>
"point relaxation stand-alone" : returns an instance of Ifpack_PointRelaxation (value of overlap is ignored).
"block relaxation" : returns an instance of Ifpack_AdditiveSchwarz<Ifpack_BlockRelaxation>
"block relaxation stand-alone)" : returns an instance of Ifpack_BlockRelaxation.
"Amesos" : returns an instance of Ifpack_AdditiveSchwarz<Ifpack_Amesos>.
"Amesos" : returns an instance of Ifpack_Amesos.
"IC" : returns an instance of Ifpack_AdditiveSchwarz<Ifpack_IC>.
"IC stand-alone" : returns an instance of Ifpack_AdditiveSchwarz<Ifpack_IC>.
"ICT" : returns an instance of Ifpack_AdditiveSchwarz<Ifpack_ICT>.
"ICT stand-alone" : returns an instance of Ifpack_ICT.
"ILU" : returns an instance of Ifpack_AdditiveSchwarz<Ifpack_ILU>.
"ILU stand-alone" : returns an instance of Ifpack_ILU.
"ILUT" : returns an instance of Ifpack_AdditiveSchwarz<Ifpack_ILUT>.
"ILUT stand-alone" : returns an instance of Ifpack_ILUT.
otherwise, Create() returns 0.

Note:: Objects in stand-alone mode cannot use reordering, variable overlap, and singleton filters. However, their construction can be slightly faster than the non stand-alone counterpart.

The following fragment of code shows the basic usage of this class.

#include "Ifpack.h"

...

Ifpack Factory;

Epetra_RowMatrix* A; // A is FillComplete()'d.
string PrecType = "ILU"; // use incomplete LU on each process
int OverlapLevel = 1; // one row of overlap among the processes
Ifpack_Preconditioner* Prec = Factory.Create(PrecType, A, OverlapLevel);
assert (Prec != 0);

Teuchos::ParameterList List;
List.set("fact: level-of-fill", 5); // use ILU(5)

IFPACK_CHK_ERR(Prec->SetParameters(List));
IFPACK_CHK_ERR(Prec->Initialize());
IFPACK_CHK_ERR(Prec->Compute());

// now Prec can be used as AztecOO preconditioner
// like for instance
AztecOO AztecOOSolver(*Problem);

// specify solver
AztecOOSolver.SetAztecOption(AZ_solver,AZ_gmres);
AztecOOSolver.SetAztecOption(AZ_output,32);

// Set Prec as preconditioning operator
AztecOOSolver.SetPrecOperator(Prec);

// Call the solver
AztecOOSolver.Iterate(1550,1e-8);

// print information on stdout
cout << *Prec;

// delete the preconditioner
delete Prec;

Author:: Marzio Sala, (formally) SNL org. 1414

Date:: Last updated on 25-Jan-05.

Member Function Documentation

Ifpack_Preconditioner * Ifpack::Create ( const string PrecType,

Epetra_RowMatrix * Matrix,

const int overlap = 0

)

Creates an instance of Ifpack_Preconditioner given the string name of the preconditioner type (can fail with bad input).

Parameters:

PrecType (In) - String name of preconditioner type to be created.

Matrix (In) - Matrix used to define the preconditioner

overlap (In) - specified overlap, defaulted to 0.

Returns 0 if the preconditioner with that input name does not exist. Otherwise, return a newly created preconditioner object. Note that the client is responsible for calling delete on the returned object once it is finished using it!

Ifpack_Preconditioner * Ifpack::Create ( EPrecType PrecType,

Epetra_RowMatrix * Matrix,

const int overlap = 0

) [static]

Creates an instance of Ifpack_Preconditioner given the enum value of the preconditioner type (can not fail, no bad input possible).

Parameters:

PrecType (In) - Enum value of preconditioner type to be created.

Matrix (In) - Matrix used to define the preconditioner

overlap (In) - specified overlap, defaulted to 0.

int Ifpack::SetParameters ( int argc,

char * argv[],

Teuchos::ParameterList & List,

string & PrecType,

int & Overlap

)

Sets the options in List from the command line.
Note: If you want full support for all parameters, consider reading in a parameter list from an XML file as supported by the Teuchos helper function Teuchos::updateParametersFromXmlFile() or Teuchos::updateParametersFromXmlStream().

Member Data Documentation

const int Ifpack::numPrecTypes [static]

Initial value:
+5 +4 +8 +1

const char * Ifpack::precTypeNames [static]

Initial value:
{ "point relaxation" ,"point relaxation stand-alone" ,"block relaxation" ,"block relaxation stand-alone" ,"block relaxation stand-alone (ILU)" ,"block relaxation stand-alone (Amesos)" ,"block relaxation (Amesos)" ,"Amesos" ,"Amesos stand-alone" ,"IC" ,"IC stand-alone" ,"ICT" ,"ICT stand-alone" ,"ILU" ,"ILU stand-alone" ,"ILUT" ,"ILUT stand-alone" ,"Chebyshev" }
List of preconditioner types as string values.

const Ifpack::EPrecType Ifpack::precTypeValues [static]

Initial value:
{ POINT_RELAXATION ,POINT_RELAXATION_STAND_ALONE ,BLOCK_RELAXATION ,BLOCK_RELAXATION_STAND_ALONE ,BLOCK_RELAXATION_STAND_ALONE_ILU ,BLOCK_RELAXATION_STAND_ALONE_AMESOS ,BLOCK_RELAXATION_AMESOS ,AMESOS ,AMESOS_STAND_ALONE ,IC ,IC_STAND_ALONE ,ICT ,ICT_STAND_ALONE ,ILU ,ILU_STAND_ALONE ,ILUT ,ILUT_STAND_ALONE ,CHEBYSHEV }
List of the preconditioner types as enum values .

const bool Ifpack::supportsUnsymmetric [static]

Initial value:
{ true ,true ,true ,true ,true ,true ,true ,true ,true ,false ,false ,false ,false ,true ,true ,true ,true ,false }
List of bools that determines if the precondtioner type supports unsymmetric matrices.

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

Ifpack.h
ifp_parameters.h
Ifpack.cpp

Generated on Wed Dec 3 12:19:07 2008 for IFPACK by

1.3.9.1


Public Types
enum	parameter { absolute_threshold, relative_threshold, drop_tolerance, fill_tolerance, relax_value, level_fill, level_overlap, num_steps, use_reciprocal, overlap_mode }
enum	EPrecType { POINT_RELAXATION, POINT_RELAXATION_STAND_ALONE, BLOCK_RELAXATION, BLOCK_RELAXATION_STAND_ALONE, BLOCK_RELAXATION_STAND_ALONE_ILU, BLOCK_RELAXATION_STAND_ALONE_AMESOS, BLOCK_RELAXATION_AMESOS, AMESOS, AMESOS_STAND_ALONE, IC, IC_STAND_ALONE, ICT, ICT_STAND_ALONE, ILU, ILU_STAND_ALONE, ILUT, ILUT_STAND_ALONE, CHEBYSHEV }
	Enum for the type of preconditioner.
Public Member Functions
Ifpack_Preconditioner *	Create (const string PrecType, Epetra_RowMatrix *Matrix, const int overlap=0)
	Creates an instance of Ifpack_Preconditioner given the string name of the preconditioner type (can fail with bad input).
int	SetParameters (int argc, char *argv[], Teuchos::ParameterList &List, string &PrecType, int &Overlap)
	Sets the options in List from the command line.
Static Public Member Functions
const char *	toString (const EPrecType precType)
	Function that gives the string name for preconditioner given its enumerication value.
Ifpack_Preconditioner *	Create (EPrecType PrecType, Epetra_RowMatrix *Matrix, const int overlap=0)
	Creates an instance of Ifpack_Preconditioner given the enum value of the preconditioner type (can not fail, no bad input possible).
Static Public Attributes
const int	numPrecTypes

const EPrecType	precTypeValues [numPrecTypes]
	List of the preconditioner types as enum values .
const char *	precTypeNames [numPrecTypes]
	List of preconditioner types as string values.
const bool	supportsUnsymmetric [numPrecTypes]
	List of bools that determines if the precondtioner type supports unsymmetric matrices.