Belos::BlockFGmresIter< ScalarType, MV, OP > Class Template Reference

This class implements the block flexible GMRES iteration, where a block Krylov subspace is constructed. The QR decomposition of block, upper Hessenberg matrix is performed each iteration to update the least squares system and give the current linear system residuals. More...

#include <BelosBlockFGmresIter.hpp>

Inheritance diagram for Belos::BlockFGmresIter< ScalarType, MV, OP >:

[legend]List of all members.

Public Types
typedef MultiVecTraits< ScalarType, MV >	MVT
typedef OperatorTraits< ScalarType, MV, OP >	OPT
typedef Teuchos::ScalarTraits< ScalarType >	SCT
typedef SCT::magnitudeType	MagnitudeType
Public Member Functions
Constructors/Destructor
	BlockFGmresIter (const Teuchos::RCP< LinearProblem< ScalarType, MV, OP > > &problem, const Teuchos::RCP< OutputManager< ScalarType > > &printer, const Teuchos::RCP< StatusTest< ScalarType, MV, OP > > &tester, const Teuchos::RCP< MatOrthoManager< ScalarType, MV, OP > > &ortho, Teuchos::ParameterList &params)
	BlockFGmresIter constructor with linear problem, solver utilities, and parameter list of solver options.
virtual	~BlockFGmresIter ()
	Destructor.
Solver methods
void	iterate ()
	This method performs block FGmres iterations until the status test indicates the need to stop or an error occurs (in which case, an std::exception is thrown).
void	initializeGmres (GmresIterationState< ScalarType, MV > newstate)
	Initialize the solver to an iterate, providing a complete state.
void	initialize ()
	Initialize the solver with the initial vectors from the linear problem or random data.
GmresIterationState< ScalarType, MV >	getState () const
	Get the current state of the linear solver.
Status methods
int	getNumIters () const
	Get the current iteration count.
void	resetNumIters (int iter=0)
	Reset the iteration count.
Teuchos::RCP< const MV >	getNativeResiduals (std::vector< MagnitudeType > *norms) const
	Get the norms of the residuals native to the solver.
Teuchos::RCP< MV >	getCurrentUpdate () const
	Get the current update to the linear system.
void	updateLSQR (int dim=-1)
	Method for updating QR factorization of upper Hessenberg matrix.
int	getCurSubspaceDim () const
	Get the dimension of the search subspace used to generate the current solution to the linear problem.
int	getMaxSubspaceDim () const
	Get the maximum dimension allocated for the search subspace.
Accessor methods
const LinearProblem< ScalarType, MV, OP > &	getProblem () const
	Get a constant reference to the linear problem.
int	getBlockSize () const
	Get the blocksize to be used by the iterative solver in solving this linear problem.
void	setBlockSize (int blockSize)
	Set the blocksize.
int	getNumBlocks () const
	Get the maximum number of blocks used by the iterative solver in solving this linear problem.
void	setNumBlocks (int numBlocks)
	Set the maximum number of blocks used by the iterative solver.
void	setSize (int blockSize, int numBlocks)
	Set the blocksize and number of blocks to be used by the iterative solver in solving this linear problem.
bool	isInitialized ()
	States whether the solver has been initialized or not.

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Detailed Description

template<class ScalarType, class MV, class OP>
class Belos::BlockFGmresIter< ScalarType, MV, OP >

This class implements the block flexible GMRES iteration, where a block Krylov subspace is constructed. The QR decomposition of block, upper Hessenberg matrix is performed each iteration to update the least squares system and give the current linear system residuals.

Author:

Teri Barth and Heidi Thornquist

Definition at line 70 of file BelosBlockFGmresIter.hpp.

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Member Typedef Documentation

template<class ScalarType, class MV, class OP>

typedef MultiVecTraits<ScalarType,MV> Belos::BlockFGmresIter< ScalarType, MV, OP >::MVT

Definition at line 77 of file BelosBlockFGmresIter.hpp.

template<class ScalarType, class MV, class OP>

typedef OperatorTraits<ScalarType,MV,OP> Belos::BlockFGmresIter< ScalarType, MV, OP >::OPT

Definition at line 78 of file BelosBlockFGmresIter.hpp.

template<class ScalarType, class MV, class OP>

typedef Teuchos::ScalarTraits<ScalarType> Belos::BlockFGmresIter< ScalarType, MV, OP >::SCT

Definition at line 79 of file BelosBlockFGmresIter.hpp.

template<class ScalarType, class MV, class OP>

typedef SCT::magnitudeType Belos::BlockFGmresIter< ScalarType, MV, OP >::MagnitudeType

Definition at line 80 of file BelosBlockFGmresIter.hpp.

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Constructor & Destructor Documentation

template<class ScalarType, class MV, class OP>

Belos::BlockFGmresIter< ScalarType, MV, OP >::BlockFGmresIter	(	const Teuchos::RCP< LinearProblem< ScalarType, MV, OP > > &	problem,
		const Teuchos::RCP< OutputManager< ScalarType > > &	printer,
		const Teuchos::RCP< StatusTest< ScalarType, MV, OP > > &	tester,
		const Teuchos::RCP< MatOrthoManager< ScalarType, MV, OP > > &	ortho,
		Teuchos::ParameterList &	params
	)

BlockFGmresIter constructor with linear problem, solver utilities, and parameter list of solver options.

This constructor takes pointers required by the linear solver, in addition to a parameter list of options for the linear solver. These options include the following:

• "Block Size" - an int specifying the block size used by the algorithm. This can also be specified using the setBlockSize() method. Default: 1
• "Num Blocks" - an int specifying the maximum number of blocks allocated for the solver basis. Default: 25
• "Restart Timers" = a bool specifying whether the timers should be restarted each time iterate() is called. Default: false
• "Keep Hessenberg" = a bool specifying whether the upper Hessenberg should be stored separately from the least squares system. Default: false

Definition at line 320 of file BelosBlockFGmresIter.hpp.

template<class ScalarType, class MV, class OP>

virtual Belos::BlockFGmresIter< ScalarType, MV, OP >::~BlockFGmresIter

(

)

[inline, virtual]

Destructor.

Definition at line 101 of file BelosBlockFGmresIter.hpp.

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Member Function Documentation

template<class ScalarType, class MV, class OP>

void Belos::BlockFGmresIter< ScalarType, MV, OP >::iterate

(

)

[virtual]

This method performs block FGmres iterations until the status test indicates the need to stop or an error occurs (in which case, an std::exception is thrown).

iterate() will first determine whether the solver is inintialized; if not, it will call initialize() using default arguments. After initialization, the solver performs block FGmres iterations until the status test evaluates as Passed, at which point the method returns to the caller.

The block FGmres iteration proceeds as follows:

1. The operator problem->applyOp() is applied to the newest blockSize vectors in the Krylov basis.
2. The resulting vectors are orthogonalized against the previous basis vectors, and made orthonormal.
3. The Hessenberg matrix is updated.
4. The least squares system is updated.

The status test is queried at the beginning of the iteration.

Possible exceptions thrown include the GmresIterationOrthoFailure.

Implements Belos::Iteration< ScalarType, MV, OP >.

Definition at line 618 of file BelosBlockFGmresIter.hpp.

template<class ScalarType, class MV, class OP>

void Belos::BlockFGmresIter< ScalarType, MV, OP >::initializeGmres

(

GmresIterationState< ScalarType, MV >

newstate

)

[virtual]

Initialize the solver to an iterate, providing a complete state.

The BlockFGmresIter contains a certain amount of state, consisting of the current Krylov basis and the associated Hessenberg matrix.

initialize() gives the user the opportunity to manually set these, although this must be done with caution, abiding by the rules given below. All notions of orthogonality and orthonormality are derived from the inner product specified by the orthogonalization manager.

Postcondition:

isInitialized() == true (see post-conditions of isInitialize())

The user has the option of specifying any component of the state using initialize(). However, these arguments are assumed to match the post-conditions specified under isInitialized(). Any necessary component of the state not given to initialize() will be generated.

Note:

For any pointer in newstate which directly points to the multivectors in the solver, the data is not copied.

Implements Belos::GmresIteration< ScalarType, MV, OP >.

Definition at line 525 of file BelosBlockFGmresIter.hpp.

template<class ScalarType, class MV, class OP>

void Belos::BlockFGmresIter< ScalarType, MV, OP >::initialize

(

)

[inline, virtual]

Initialize the solver with the initial vectors from the linear problem or random data.

Implements Belos::Iteration< ScalarType, MV, OP >.

Definition at line 157 of file BelosBlockFGmresIter.hpp.

template<class ScalarType, class MV, class OP>

GmresIterationState<ScalarType,MV> Belos::BlockFGmresIter< ScalarType, MV, OP >::getState

(

)

const [inline, virtual]

Get the current state of the linear solver.

The data is only valid if isInitialized() == true.

Returns:

A GmresIterationState object containing const pointers to the current solver state.

Implements Belos::GmresIteration< ScalarType, MV, OP >.

Definition at line 170 of file BelosBlockFGmresIter.hpp.

template<class ScalarType, class MV, class OP>

int Belos::BlockFGmresIter< ScalarType, MV, OP >::getNumIters

(

)

const [inline, virtual]

Get the current iteration count.

Implements Belos::Iteration< ScalarType, MV, OP >.

Definition at line 188 of file BelosBlockFGmresIter.hpp.

template<class ScalarType, class MV, class OP>

void Belos::BlockFGmresIter< ScalarType, MV, OP >::resetNumIters

(

int

iter = 0

)

[inline, virtual]

Reset the iteration count.

Implements Belos::Iteration< ScalarType, MV, OP >.

Definition at line 191 of file BelosBlockFGmresIter.hpp.

template<class ScalarType, class MV, class OP>

Teuchos::RCP< const MV > Belos::BlockFGmresIter< ScalarType, MV, OP >::getNativeResiduals

(

std::vector< MagnitudeType > *

norms

)

const

Get the norms of the residuals native to the solver.

Returns:

A std::vector of length blockSize containing the native residuals.

Definition at line 503 of file BelosBlockFGmresIter.hpp.

template<class ScalarType, class MV, class OP>

Teuchos::RCP< MV > Belos::BlockFGmresIter< ScalarType, MV, OP >::getCurrentUpdate

(

)

const [virtual]

Get the current update to the linear system.

Note:

Some solvers, like flexible GMRES, do not compute updates to the solution every iteration. This method forces its computation. Other solvers, like CG, update the solution each iteration, so this method will return a zero std::vector indicating that the linear problem contains the current solution.

Implements Belos::Iteration< ScalarType, MV, OP >.

Definition at line 461 of file BelosBlockFGmresIter.hpp.

template<class ScalarType, class MV, class OP>

void Belos::BlockFGmresIter< ScalarType, MV, OP >::updateLSQR

(

int

dim = -1

)

[virtual]

Method for updating QR factorization of upper Hessenberg matrix.

Note:

If dim >= getCurSubspaceDim() and dim < getMaxSubspaceDim(), then the dim-th equations of the least squares problem will be updated.

Implements Belos::GmresIteration< ScalarType, MV, OP >.

Definition at line 716 of file BelosBlockFGmresIter.hpp.

template<class ScalarType, class MV, class OP>

int Belos::BlockFGmresIter< ScalarType, MV, OP >::getCurSubspaceDim

(

)

const [inline, virtual]

Get the dimension of the search subspace used to generate the current solution to the linear problem.

Implements Belos::GmresIteration< ScalarType, MV, OP >.

Definition at line 212 of file BelosBlockFGmresIter.hpp.

template<class ScalarType, class MV, class OP>

int Belos::BlockFGmresIter< ScalarType, MV, OP >::getMaxSubspaceDim

(

)

const [inline, virtual]

Get the maximum dimension allocated for the search subspace.

Implements Belos::GmresIteration< ScalarType, MV, OP >.

Definition at line 218 of file BelosBlockFGmresIter.hpp.

template<class ScalarType, class MV, class OP>

const LinearProblem<ScalarType,MV,OP>& Belos::BlockFGmresIter< ScalarType, MV, OP >::getProblem

(

)

const [inline, virtual]

Get a constant reference to the linear problem.

Implements Belos::Iteration< ScalarType, MV, OP >.

Definition at line 227 of file BelosBlockFGmresIter.hpp.

template<class ScalarType, class MV, class OP>

int Belos::BlockFGmresIter< ScalarType, MV, OP >::getBlockSize

(

)

const [inline, virtual]

Get the blocksize to be used by the iterative solver in solving this linear problem.

Implements Belos::Iteration< ScalarType, MV, OP >.

Definition at line 230 of file BelosBlockFGmresIter.hpp.

template<class ScalarType, class MV, class OP>

void Belos::BlockFGmresIter< ScalarType, MV, OP >::setBlockSize

(

int

blockSize

)

[inline, virtual]

Set the blocksize.

Implements Belos::Iteration< ScalarType, MV, OP >.

Definition at line 233 of file BelosBlockFGmresIter.hpp.

template<class ScalarType, class MV, class OP>

int Belos::BlockFGmresIter< ScalarType, MV, OP >::getNumBlocks

(

)

const [inline]

Get the maximum number of blocks used by the iterative solver in solving this linear problem.

Definition at line 236 of file BelosBlockFGmresIter.hpp.

template<class ScalarType, class MV, class OP>

void Belos::BlockFGmresIter< ScalarType, MV, OP >::setNumBlocks

(

int

numBlocks

)

[inline]

Set the maximum number of blocks used by the iterative solver.

Definition at line 239 of file BelosBlockFGmresIter.hpp.

template<class ScalarType, class MV, class OP>

void Belos::BlockFGmresIter< ScalarType, MV, OP >::setSize	(	int	blockSize,
		int	numBlocks
	)			[virtual]

Set the blocksize and number of blocks to be used by the iterative solver in solving this linear problem.

Changing either the block size or the number of blocks will reset the solver to an uninitialized state.

Implements Belos::GmresIteration< ScalarType, MV, OP >.

Definition at line 349 of file BelosBlockFGmresIter.hpp.

template<class ScalarType, class MV, class OP>

bool Belos::BlockFGmresIter< ScalarType, MV, OP >::isInitialized

(

)

[inline, virtual]

States whether the solver has been initialized or not.

Implements Belos::Iteration< ScalarType, MV, OP >.

Definition at line 250 of file BelosBlockFGmresIter.hpp.

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

• BelosBlockFGmresIter.hpp

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