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Amesos_Scalapack Class Reference

Amesos_Scalapack: A serial and parallel dense solver. For now, we implement only the unsymmetric ScaLAPACK solver. More...

#include <Amesos_Scalapack.h>

Inheritance diagram for Amesos_Scalapack:
Inheritance graph
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List of all members.

Protected Attributes

int iam_
int NumGlobalElements_
int NumGlobalNonzeros_
int nprow_
int npcol_
int ictxt_
int m_per_p_
int DescA_ [10]
Epetra_MapScaLAPACK1DMap_
Epetra_CrsMatrixScaLAPACK1DMatrix_
Epetra_MapVectorMap_
std::vector< double > DenseA_
std::vector< int > Ipiv_
int NumOurRows_
int NumOurColumns_
bool UseTranspose_
const Epetra_LinearProblemProblem_
double ConTime_
double SymTime_
double NumTime_
double SolTime_
double VecTime_
double MatTime_
bool TwoD_distribution_
int grid_nb_
int mypcol_
int myprow_
Epetra_CrsMatrixFatOut_
int nb_
int lda_
Epetra_TimeTime_

Private Member Functions

int RedistributeA ()
int ConvertToScalapack ()
int PerformNumericFactorization ()
 Amesos_Scalapack (const Epetra_LinearProblem &LinearProblem)
 Amesos_Scalapack Constructor.
 ~Amesos_Scalapack (void)
 Amesos_Scalapack Destructor.
int SymbolicFactorization ()
 Performs SymbolicFactorization on the matrix A.
int NumericFactorization ()
 Performs NumericFactorization on the matrix A.
int Solve ()
 Solves A X = B (or AT X = B)
const Epetra_LinearProblemGetProblem () const
 Get a pointer to the Problem.
bool MatrixShapeOK () const
 Returns true if SCALAPACK can handle this matrix shape.
int SetUseTranspose (bool UseTranspose)
 SetUseTranpose(true) is more efficient in Amesos_Scalapack.
bool UseTranspose () const
 Returns the current UseTranspose setting.
const Epetra_CommComm () const
 Returns a pointer to the Epetra_Comm communicator associated with this matrix.
int SetParameters (Teuchos::ParameterList &ParameterList)
 Updates internal variables.
int NumSymbolicFact () const
 Returns the number of symbolic factorizations performed by this object.
int NumNumericFact () const
 Returns the number of numeric factorizations performed by this object.
int NumSolve () const
 Returns the number of solves performed by this object.
void PrintTiming () const
 Print timing information.
void PrintStatus () const
 Print information about the factorization and solution phases.
void GetTiming (Teuchos::ParameterList &TimingParameterList) const
 Extracts timing information from the current solver and places it in the parameter list.

Detailed Description

Amesos_Scalapack: A serial and parallel dense solver. For now, we implement only the unsymmetric ScaLAPACK solver.

Amesos_Scalapack, an object-oriented wrapper for LAPACK and ScaLAPACK, will solve a linear systems of equations: A X = B using Epetra objects and the ScaLAPACK library, where A is an Epetra_RowMatrix and X and B are Epetra_MultiVector objects.



Amesos_Scalapack can be competitive for matrices that are not particularly sparse. ScaLAPACK solves matrices for which the fill-in is roughly 10% to 20% of the matrix size in time comparable to that achieve by other Amesos classes. Amesos_Scalapack scales well and hence its performance advantage will be largest when large number of processes are involved.



Amesos_Scalapack uses the ScaLAPACK functions PDGETRF and PDGETRS if more than one process is used. If only one process is used, Amesos_ScaLAPACK uses the LAPACK function PDGETRF and PDGETRS.



AmesosScaLAPACK uses full partial pivoting and will therefore provide answers that are at least as accurate as any direct sparse solver.



AmesosScalapack makes sense under the following circumstances:

Common control parameters :

Amesos_Scalapack supports the following parameters which are common to across multiple Amesos solvers:

Amesos_Scalapack supports the following parameters specific to Amesos_Scalapack.
Teuchos::ParameterList ScalapackParams = ParameterList.sublist("Scalapack") ;

Limitations:

None of the following limitations would be particularly difficult to remove.



The present implementation limits the number of right hand sides to the number of rows assigned to each process. i.e. nrhs < n/p.



The present implementation does not take advantage of symmetric or symmetric positive definite matrices, although ScaLAPACK has separate routines to take advantages of such matrices.

Definition at line 146 of file Amesos_Scalapack.h.


Constructor & Destructor Documentation

Amesos_Scalapack::Amesos_Scalapack ( const Epetra_LinearProblem LinearProblem)

Amesos_Scalapack Constructor.

Creates an Amesos_Scalapack instance, using an Epetra_LinearProblem, passing in an already-defined Epetra_LinearProblem object.

Note: The operator in LinearProblem must be an Epetra_RowMatrix.

Definition at line 50 of file Amesos_Scalapack.cpp.

Amesos_Scalapack::~Amesos_Scalapack ( void  )

Amesos_Scalapack Destructor.

Completely deletes an Amesos_Scalapack object.

Definition at line 71 of file Amesos_Scalapack.cpp.


Member Function Documentation

int Amesos_Scalapack::SymbolicFactorization ( ) [virtual]

Performs SymbolicFactorization on the matrix A.

There is no symbolic factorization phase in ScaLAPACK, as it operates only on dense matrices. Hence, Amesos_Scalapack::SymbolicFactorization() takes no action.

Returns:
Integer error code, set to 0 if successful.

Implements Amesos_BaseSolver.

Definition at line 778 of file Amesos_Scalapack.cpp.

int Amesos_Scalapack::NumericFactorization ( ) [virtual]

Performs NumericFactorization on the matrix A.

In addition to performing numeric factorization on the matrix A, the call to NumericFactorization() implies that no change will be made to the underlying matrix without a subsequent call to NumericFactorization().

preconditions:

postconditions:

  • nprow_, npcol_, DescA_
  • DenseA will be factored
  • Ipiv_ contains the pivots
Returns:
Integer error code, set to 0 if successful.

Implements Amesos_BaseSolver.

Definition at line 789 of file Amesos_Scalapack.cpp.

int Amesos_Scalapack::Solve ( void  ) [virtual]

Solves A X = B (or AT X = B)

preconditions:

postconditions:

  • X will be set such that A X = B (or AT X = B), within the limits of the accuracy of the the Scalapack solver.
Returns:
Integer error code, set to 0 if successful.

Implements Amesos_BaseSolver.

Definition at line 810 of file Amesos_Scalapack.cpp.

const Epetra_LinearProblem* Amesos_Scalapack::GetProblem ( ) const [inline, virtual]

Get a pointer to the Problem.

Implements Amesos_BaseSolver.

Definition at line 246 of file Amesos_Scalapack.h.

bool Amesos_Scalapack::MatrixShapeOK ( ) const [virtual]

Returns true if SCALAPACK can handle this matrix shape.

Returns true if the matrix shape is one that SCALAPACK can handle. SCALAPACK only works with square matrices.

Implements Amesos_BaseSolver.

Definition at line 769 of file Amesos_Scalapack.cpp.

int Amesos_Scalapack::SetUseTranspose ( bool  UseTranspose) [inline, virtual]

SetUseTranpose(true) is more efficient in Amesos_Scalapack.

Implements Amesos_BaseSolver.

Definition at line 267 of file Amesos_Scalapack.h.

bool Amesos_Scalapack::UseTranspose ( ) const [inline, virtual]

Returns the current UseTranspose setting.

Implements Amesos_BaseSolver.

Definition at line 270 of file Amesos_Scalapack.h.

const Epetra_Comm& Amesos_Scalapack::Comm ( ) const [inline, virtual]

Returns a pointer to the Epetra_Comm communicator associated with this matrix.

Implements Amesos_BaseSolver.

Definition at line 273 of file Amesos_Scalapack.h.

int Amesos_Scalapack::SetParameters ( Teuchos::ParameterList ParameterList) [virtual]

Updates internal variables.

<br >Preconditions:

  • None.

<br >Postconditions:

  • Internal variables controlling the factorization and solve will be updated and take effect on all subsequent calls to NumericFactorization() and Solve().
  • All parameters whose value are to differ from the default values must be included in ParameterList. Parameters not specified in ParameterList revert to their default values.
Returns:
Integer error code, set to 0 if successful.

Implements Amesos_BaseSolver.

Definition at line 657 of file Amesos_Scalapack.cpp.

int Amesos_Scalapack::NumSymbolicFact ( ) const [inline, virtual]

Returns the number of symbolic factorizations performed by this object.

Implements Amesos_BaseSolver.

Definition at line 295 of file Amesos_Scalapack.h.

int Amesos_Scalapack::NumNumericFact ( ) const [inline, virtual]

Returns the number of numeric factorizations performed by this object.

Implements Amesos_BaseSolver.

Definition at line 298 of file Amesos_Scalapack.h.

int Amesos_Scalapack::NumSolve ( ) const [inline, virtual]

Returns the number of solves performed by this object.

Implements Amesos_BaseSolver.

Definition at line 301 of file Amesos_Scalapack.h.

void Amesos_Scalapack::PrintTiming ( ) const [virtual]

Print timing information.

Implements Amesos_BaseSolver.

Definition at line 1015 of file Amesos_Scalapack.cpp.

void Amesos_Scalapack::PrintStatus ( ) const [virtual]

Print information about the factorization and solution phases.

Implements Amesos_BaseSolver.

Definition at line 994 of file Amesos_Scalapack.cpp.

void Amesos_Scalapack::GetTiming ( Teuchos::ParameterList TimingParameterList) const [inline, virtual]

Extracts timing information from the current solver and places it in the parameter list.

Reimplemented from Amesos_BaseSolver.

Definition at line 310 of file Amesos_Scalapack.h.

int Amesos_Scalapack::RedistributeA ( ) [private]

Definition at line 124 of file Amesos_Scalapack.cpp.

int Amesos_Scalapack::ConvertToScalapack ( ) [private]

Definition at line 510 of file Amesos_Scalapack.cpp.

int Amesos_Scalapack::PerformNumericFactorization ( ) [private]

Definition at line 694 of file Amesos_Scalapack.cpp.


Member Data Documentation

int Amesos_Scalapack::iam_ [protected]

Definition at line 355 of file Amesos_Scalapack.h.

Definition at line 357 of file Amesos_Scalapack.h.

Definition at line 358 of file Amesos_Scalapack.h.

int Amesos_Scalapack::nprow_ [protected]

Definition at line 363 of file Amesos_Scalapack.h.

int Amesos_Scalapack::npcol_ [protected]

Definition at line 364 of file Amesos_Scalapack.h.

int Amesos_Scalapack::ictxt_ [protected]

Definition at line 365 of file Amesos_Scalapack.h.

int Amesos_Scalapack::m_per_p_ [protected]

Definition at line 366 of file Amesos_Scalapack.h.

int Amesos_Scalapack::DescA_[10] [protected]

Definition at line 367 of file Amesos_Scalapack.h.

Definition at line 369 of file Amesos_Scalapack.h.

Definition at line 371 of file Amesos_Scalapack.h.

Definition at line 373 of file Amesos_Scalapack.h.

std::vector<double> Amesos_Scalapack::DenseA_ [protected]

Definition at line 374 of file Amesos_Scalapack.h.

std::vector<int> Amesos_Scalapack::Ipiv_ [protected]

Definition at line 375 of file Amesos_Scalapack.h.

Definition at line 376 of file Amesos_Scalapack.h.

Definition at line 377 of file Amesos_Scalapack.h.

Definition at line 380 of file Amesos_Scalapack.h.

Definition at line 381 of file Amesos_Scalapack.h.

double Amesos_Scalapack::ConTime_ [protected]

Definition at line 385 of file Amesos_Scalapack.h.

double Amesos_Scalapack::SymTime_ [protected]

Definition at line 386 of file Amesos_Scalapack.h.

double Amesos_Scalapack::NumTime_ [protected]

Definition at line 387 of file Amesos_Scalapack.h.

double Amesos_Scalapack::SolTime_ [protected]

Definition at line 388 of file Amesos_Scalapack.h.

double Amesos_Scalapack::VecTime_ [protected]

Definition at line 389 of file Amesos_Scalapack.h.

double Amesos_Scalapack::MatTime_ [protected]

Definition at line 390 of file Amesos_Scalapack.h.

Definition at line 395 of file Amesos_Scalapack.h.

int Amesos_Scalapack::grid_nb_ [protected]

Definition at line 396 of file Amesos_Scalapack.h.

int Amesos_Scalapack::mypcol_ [protected]

Definition at line 397 of file Amesos_Scalapack.h.

int Amesos_Scalapack::myprow_ [protected]

Definition at line 398 of file Amesos_Scalapack.h.

Definition at line 399 of file Amesos_Scalapack.h.

int Amesos_Scalapack::nb_ [protected]

Definition at line 404 of file Amesos_Scalapack.h.

int Amesos_Scalapack::lda_ [protected]

Definition at line 405 of file Amesos_Scalapack.h.

Definition at line 407 of file Amesos_Scalapack.h.


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