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

This class implements the block 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 <BelosBlockGmresIter.hpp>

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

Classes
struct	CheckList

Public Types
typedef MultiVecTraits < ScalarType, MV >	MVT
typedef OperatorTraits < ScalarType, MV, OP >	OPT
typedef Teuchos::ScalarTraits < ScalarType >	SCT
typedef SCT::magnitudeType	MagnitudeType

Private Member Functions
std::string	accuracyCheck (const CheckList &chk, const std::string &where) const
	Check accuracy of Arnoldi factorization. More...
void	setStateSize ()
	Method for initalizing the state storage needed by block GMRES. More...

Private Attributes
const Teuchos::RCP < LinearProblem< ScalarType, MV, OP > >	lp_
const Teuchos::RCP < OutputManager< ScalarType > >	om_
const Teuchos::RCP< StatusTest < ScalarType, MV, OP > >	stest_
const Teuchos::RCP < OrthoManager< ScalarType, MV > >	ortho_
int	blockSize_
int	numBlocks_
Teuchos::SerialDenseVector < int, ScalarType >	beta
Teuchos::SerialDenseVector < int, ScalarType >	sn
Teuchos::SerialDenseVector < int, MagnitudeType >	cs
bool	initialized_
bool	stateStorageInitialized_
bool	keepHessenberg_
bool	initHessenberg_
int	curDim_
int	iter_
Teuchos::RCP< MV >	V_
Teuchos::RCP < Teuchos::SerialDenseMatrix < int, ScalarType > >	H_
Teuchos::RCP < Teuchos::SerialDenseMatrix < int, ScalarType > >	R_
Teuchos::RCP < Teuchos::SerialDenseMatrix < int, ScalarType > >	z_

Constructors/Destructor
	BlockGmresIter (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)
	BlockGmresIter constructor with linear problem, solver utilities, and parameter list of solver options. More...
virtual	~BlockGmresIter ()
	Destructor. More...

Solver methods
void	iterate ()
	This method performs block Gmres iterations until the status test indicates the need to stop or an error occurs (in which case, an std::exception is thrown). More...
void	initializeGmres (GmresIterationState< ScalarType, MV > &newstate)
	Initialize the solver to an iterate, providing a complete state. More...
void	initialize ()
	Initialize the solver with the initial vectors from the linear problem or random data. More...
GmresIterationState < ScalarType, MV >	getState () const
	Get the current state of the linear solver. More...

Status methods
int	getNumIters () const
	Get the current iteration count. More...
void	resetNumIters (int iter=0)
	Reset the iteration count. More...
Teuchos::RCP< const MV >	getNativeResiduals (std::vector< MagnitudeType > *norms) const
	Get the norms of the residuals native to the solver. More...
Teuchos::RCP< MV >	getCurrentUpdate () const
	Get the current update to the linear system. More...
void	updateLSQR (int dim=-1)
	Method for updating QR factorization of upper Hessenberg matrix. More...
int	getCurSubspaceDim () const
	Get the dimension of the search subspace used to generate the current solution to the linear problem. More...
int	getMaxSubspaceDim () const
	Get the maximum dimension allocated for the search subspace. More...

Accessor methods
const LinearProblem < ScalarType, MV, OP > &	getProblem () const
	Get a constant reference to the linear problem. More...
int	getBlockSize () const
	Get the blocksize to be used by the iterative solver in solving this linear problem. More...
void	setBlockSize (int blockSize)
	Set the blocksize. More...
int	getNumBlocks () const
	Get the maximum number of blocks used by the iterative solver in solving this linear problem. More...
void	setNumBlocks (int numBlocks)
	Set the maximum number of blocks used by the iterative solver. More...
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. More...
bool	isInitialized ()
	States whether the solver has been initialized or not. More...

Detailed Description

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

This class implements the block 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 52 of file BelosBlockGmresIter.hpp.

Member Typedef Documentation

template<class ScalarType , class MV , class OP >

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

Definition at line 59 of file BelosBlockGmresIter.hpp.

template<class ScalarType , class MV , class OP >

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

Definition at line 60 of file BelosBlockGmresIter.hpp.

template<class ScalarType , class MV , class OP >

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

Definition at line 61 of file BelosBlockGmresIter.hpp.

template<class ScalarType , class MV , class OP >

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

Definition at line 62 of file BelosBlockGmresIter.hpp.

Constructor & Destructor Documentation

template<class ScalarType , class MV , class OP >

Belos::BlockGmresIter< ScalarType, MV, OP >::BlockGmresIter	(	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
	)

BlockGmresIter 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 BelosBlockGmresIter.hpp.

template<class ScalarType , class MV , class OP >

virtual Belos::BlockGmresIter< ScalarType, MV, OP >::~BlockGmresIter ( )

inlinevirtual

Destructor.

Definition at line 83 of file BelosBlockGmresIter.hpp.

Member Function Documentation

template<class ScalarType , class MV , class OP >

void Belos::BlockGmresIter< ScalarType, MV, OP >::iterate ( )

virtual

This method performs block Gmres 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 Gmres iterations until the status test evaluates as Passed, at which point the method returns to the caller.

The block Gmres 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 639 of file BelosBlockGmresIter.hpp.

template<class ScalarType , class MV , class OP >

void Belos::BlockGmresIter< ScalarType, MV, OP >::initializeGmres ( GmresIterationState< ScalarType, MV > &  newstate )

virtual

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

The BlockGmresIter 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 547 of file BelosBlockGmresIter.hpp.

template<class ScalarType , class MV , class OP >

void Belos::BlockGmresIter< ScalarType, MV, OP >::initialize ( )

inlinevirtual

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

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

Definition at line 139 of file BelosBlockGmresIter.hpp.

template<class ScalarType , class MV , class OP >

GmresIterationState<ScalarType,MV> Belos::BlockGmresIter< ScalarType, MV, OP >::getState ( ) const

inlinevirtual

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 152 of file BelosBlockGmresIter.hpp.

template<class ScalarType , class MV , class OP >

int Belos::BlockGmresIter< ScalarType, MV, OP >::getNumIters ( ) const

inlinevirtual

Get the current iteration count.

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

Definition at line 169 of file BelosBlockGmresIter.hpp.

template<class ScalarType , class MV , class OP >

void Belos::BlockGmresIter< ScalarType, MV, OP >::resetNumIters ( int  iter = 0 )

inlinevirtual

Reset the iteration count.

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

Definition at line 172 of file BelosBlockGmresIter.hpp.

template<class ScalarType , class MV , class OP >

Teuchos::RCP< const MV > Belos::BlockGmresIter< 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 525 of file BelosBlockGmresIter.hpp.

template<class ScalarType , class MV , class OP >

Teuchos::RCP< MV > Belos::BlockGmresIter< ScalarType, MV, OP >::getCurrentUpdate ( ) const

virtual

Get the current update to the linear system.

Note

Some solvers, like 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 483 of file BelosBlockGmresIter.hpp.

template<class ScalarType , class MV , class OP >

void Belos::BlockGmresIter< 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 748 of file BelosBlockGmresIter.hpp.

template<class ScalarType , class MV , class OP >

int Belos::BlockGmresIter< ScalarType, MV, OP >::getCurSubspaceDim ( ) const

inlinevirtual

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 193 of file BelosBlockGmresIter.hpp.

template<class ScalarType , class MV , class OP >

int Belos::BlockGmresIter< ScalarType, MV, OP >::getMaxSubspaceDim ( ) const

inlinevirtual

Get the maximum dimension allocated for the search subspace.

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

Definition at line 199 of file BelosBlockGmresIter.hpp.

template<class ScalarType , class MV , class OP >

const LinearProblem<ScalarType,MV,OP>& Belos::BlockGmresIter< ScalarType, MV, OP >::getProblem ( ) const

inlinevirtual

Get a constant reference to the linear problem.

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

Definition at line 208 of file BelosBlockGmresIter.hpp.

template<class ScalarType , class MV , class OP >

int Belos::BlockGmresIter< ScalarType, MV, OP >::getBlockSize ( ) const

inlinevirtual

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

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

Definition at line 211 of file BelosBlockGmresIter.hpp.

template<class ScalarType , class MV , class OP >

void Belos::BlockGmresIter< ScalarType, MV, OP >::setBlockSize ( int  blockSize )

inlinevirtual

Set the blocksize.

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

Definition at line 214 of file BelosBlockGmresIter.hpp.

template<class ScalarType , class MV , class OP >

int Belos::BlockGmresIter< 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 217 of file BelosBlockGmresIter.hpp.

template<class ScalarType , class MV , class OP >

void Belos::BlockGmresIter< ScalarType, MV, OP >::setNumBlocks ( int  numBlocks )

inline

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

Definition at line 220 of file BelosBlockGmresIter.hpp.

template<class ScalarType , class MV , class OP >

void Belos::BlockGmresIter< 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 360 of file BelosBlockGmresIter.hpp.

template<class ScalarType , class MV , class OP >

bool Belos::BlockGmresIter< ScalarType, MV, OP >::isInitialized ( )

inlinevirtual

States whether the solver has been initialized or not.

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

Definition at line 231 of file BelosBlockGmresIter.hpp.

template<class ScalarType , class MV , class OP >

std::string Belos::BlockGmresIter< ScalarType, MV, OP >::accuracyCheck ( const CheckList &  chk, const std::string &  where  ) const

private

Check accuracy of Arnoldi factorization.

Definition at line 857 of file BelosBlockGmresIter.hpp.

template<class ScalarType , class MV , class OP >

void Belos::BlockGmresIter< ScalarType, MV, OP >::setStateSize ( )

private

Method for initalizing the state storage needed by block GMRES.

Definition at line 388 of file BelosBlockGmresIter.hpp.

Member Data Documentation

template<class ScalarType , class MV , class OP >

const Teuchos::RCP<LinearProblem<ScalarType,MV,OP> > Belos::BlockGmresIter< ScalarType, MV, OP >::lp_

private

Definition at line 257 of file BelosBlockGmresIter.hpp.

template<class ScalarType , class MV , class OP >

const Teuchos::RCP<OutputManager<ScalarType> > Belos::BlockGmresIter< ScalarType, MV, OP >::om_

private

Definition at line 258 of file BelosBlockGmresIter.hpp.

template<class ScalarType , class MV , class OP >

const Teuchos::RCP<StatusTest<ScalarType,MV,OP> > Belos::BlockGmresIter< ScalarType, MV, OP >::stest_

private

Definition at line 259 of file BelosBlockGmresIter.hpp.

template<class ScalarType , class MV , class OP >

const Teuchos::RCP<OrthoManager<ScalarType,MV> > Belos::BlockGmresIter< ScalarType, MV, OP >::ortho_

private

Definition at line 260 of file BelosBlockGmresIter.hpp.

template<class ScalarType , class MV , class OP >

int Belos::BlockGmresIter< ScalarType, MV, OP >::blockSize_

private

Definition at line 267 of file BelosBlockGmresIter.hpp.

template<class ScalarType , class MV , class OP >

int Belos::BlockGmresIter< ScalarType, MV, OP >::numBlocks_

private

Definition at line 269 of file BelosBlockGmresIter.hpp.

template<class ScalarType , class MV , class OP >

Teuchos::SerialDenseVector<int,ScalarType> Belos::BlockGmresIter< ScalarType, MV, OP >::beta

private

Definition at line 272 of file BelosBlockGmresIter.hpp.

template<class ScalarType , class MV , class OP >

Teuchos::SerialDenseVector<int,ScalarType> Belos::BlockGmresIter< ScalarType, MV, OP >::sn

private

Definition at line 272 of file BelosBlockGmresIter.hpp.

template<class ScalarType , class MV , class OP >

Teuchos::SerialDenseVector<int,MagnitudeType> Belos::BlockGmresIter< ScalarType, MV, OP >::cs

private

Definition at line 273 of file BelosBlockGmresIter.hpp.

template<class ScalarType , class MV , class OP >

bool Belos::BlockGmresIter< ScalarType, MV, OP >::initialized_

private

Definition at line 281 of file BelosBlockGmresIter.hpp.

template<class ScalarType , class MV , class OP >

bool Belos::BlockGmresIter< ScalarType, MV, OP >::stateStorageInitialized_

private

Definition at line 286 of file BelosBlockGmresIter.hpp.

template<class ScalarType , class MV , class OP >

bool Belos::BlockGmresIter< ScalarType, MV, OP >::keepHessenberg_

private

Definition at line 291 of file BelosBlockGmresIter.hpp.

template<class ScalarType , class MV , class OP >

bool Belos::BlockGmresIter< ScalarType, MV, OP >::initHessenberg_

private

Definition at line 295 of file BelosBlockGmresIter.hpp.

template<class ScalarType , class MV , class OP >

int Belos::BlockGmresIter< ScalarType, MV, OP >::curDim_

private

Definition at line 298 of file BelosBlockGmresIter.hpp.

template<class ScalarType , class MV , class OP >

int Belos::BlockGmresIter< ScalarType, MV, OP >::iter_

private

Definition at line 298 of file BelosBlockGmresIter.hpp.

template<class ScalarType , class MV , class OP >

Teuchos::RCP<MV> Belos::BlockGmresIter< ScalarType, MV, OP >::V_

private

Definition at line 303 of file BelosBlockGmresIter.hpp.

template<class ScalarType , class MV , class OP >

Teuchos::RCP<Teuchos::SerialDenseMatrix<int,ScalarType> > Belos::BlockGmresIter< ScalarType, MV, OP >::H_

private

Definition at line 308 of file BelosBlockGmresIter.hpp.

template<class ScalarType , class MV , class OP >

Teuchos::RCP<Teuchos::SerialDenseMatrix<int,ScalarType> > Belos::BlockGmresIter< ScalarType, MV, OP >::R_

private

Definition at line 313 of file BelosBlockGmresIter.hpp.

template<class ScalarType , class MV , class OP >

Teuchos::RCP<Teuchos::SerialDenseMatrix<int,ScalarType> > Belos::BlockGmresIter< ScalarType, MV, OP >::z_

private

Definition at line 314 of file BelosBlockGmresIter.hpp.

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

• BelosBlockGmresIter.hpp