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

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

#include <BelosPseudoBlockGmresIter.hpp>

Inheritance diagram for Belos::PseudoBlockGmresIter< ScalarType, MV, OP >:
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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
 PseudoBlockGmresIter (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)
 PseudoBlockGmresIter constructor with linear problem, solver utilities, and parameter list of solver options.
virtual ~PseudoBlockGmresIter ()
 Destructor.
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).
void initialize (PseudoBlockGmresIterState< 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.
PseudoBlockGmresIterState
< 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.
bool isInitialized ()
 States whether the solver has been initialized or not.

Detailed Description

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

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

Author:
Heidi Thornquist

Definition at line 155 of file BelosPseudoBlockGmresIter.hpp.


Member Typedef Documentation

template<class ScalarType , class MV , class OP >
typedef MultiVecTraits<ScalarType,MV> Belos::PseudoBlockGmresIter< ScalarType, MV, OP >::MVT

Definition at line 162 of file BelosPseudoBlockGmresIter.hpp.

template<class ScalarType , class MV , class OP >
typedef OperatorTraits<ScalarType,MV,OP> Belos::PseudoBlockGmresIter< ScalarType, MV, OP >::OPT

Definition at line 163 of file BelosPseudoBlockGmresIter.hpp.

template<class ScalarType , class MV , class OP >
typedef Teuchos::ScalarTraits<ScalarType> Belos::PseudoBlockGmresIter< ScalarType, MV, OP >::SCT

Definition at line 164 of file BelosPseudoBlockGmresIter.hpp.

template<class ScalarType , class MV , class OP >
typedef SCT::magnitudeType Belos::PseudoBlockGmresIter< ScalarType, MV, OP >::MagnitudeType

Definition at line 165 of file BelosPseudoBlockGmresIter.hpp.


Constructor & Destructor Documentation

template<class ScalarType , class MV , class OP >
Belos::PseudoBlockGmresIter< ScalarType, MV, OP >::PseudoBlockGmresIter ( 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 
)

PseudoBlockGmresIter 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

Definition at line 399 of file BelosPseudoBlockGmresIter.hpp.

template<class ScalarType , class MV , class OP >
virtual Belos::PseudoBlockGmresIter< ScalarType, MV, OP >::~PseudoBlockGmresIter ( ) [inline, virtual]

Destructor.

Definition at line 185 of file BelosPseudoBlockGmresIter.hpp.


Member Function Documentation

template<class ScalarType , class MV , class OP >
void Belos::PseudoBlockGmresIter< 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 PseudoBlockGmresIterOrthoFailure.

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

Definition at line 682 of file BelosPseudoBlockGmresIter.hpp.

template<class ScalarType , class MV , class OP >
void Belos::PseudoBlockGmresIter< ScalarType, MV, OP >::initialize ( PseudoBlockGmresIterState< ScalarType, MV >  newstate)

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

The PseudoBlockGmresIter 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.

Definition at line 508 of file BelosPseudoBlockGmresIter.hpp.

template<class ScalarType , class MV , class OP >
void Belos::PseudoBlockGmresIter< 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 241 of file BelosPseudoBlockGmresIter.hpp.

template<class ScalarType , class MV , class OP >
PseudoBlockGmresIterState<ScalarType,MV> Belos::PseudoBlockGmresIter< ScalarType, MV, OP >::getState ( ) const [inline]

Get the current state of the linear solver.

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

Returns:
A PseudoBlockGmresIterState object containing const pointers to the current solver state.

Definition at line 254 of file BelosPseudoBlockGmresIter.hpp.

template<class ScalarType , class MV , class OP >
int Belos::PseudoBlockGmresIter< ScalarType, MV, OP >::getNumIters ( ) const [inline, virtual]

Get the current iteration count.

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

Definition at line 279 of file BelosPseudoBlockGmresIter.hpp.

template<class ScalarType , class MV , class OP >
void Belos::PseudoBlockGmresIter< ScalarType, MV, OP >::resetNumIters ( int  iter = 0) [inline, virtual]

Reset the iteration count.

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

Definition at line 282 of file BelosPseudoBlockGmresIter.hpp.

template<class ScalarType , class MV , class OP >
Teuchos::RCP< const MV > Belos::PseudoBlockGmresIter< 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 486 of file BelosPseudoBlockGmresIter.hpp.

template<class ScalarType , class MV , class OP >
Teuchos::RCP< MV > Belos::PseudoBlockGmresIter< 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 441 of file BelosPseudoBlockGmresIter.hpp.

template<class ScalarType , class MV , class OP >
void Belos::PseudoBlockGmresIter< ScalarType, MV, OP >::updateLSQR ( int  dim = -1)

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.

Definition at line 815 of file BelosPseudoBlockGmresIter.hpp.

template<class ScalarType , class MV , class OP >
int Belos::PseudoBlockGmresIter< ScalarType, MV, OP >::getCurSubspaceDim ( ) const [inline]

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

Definition at line 303 of file BelosPseudoBlockGmresIter.hpp.

template<class ScalarType , class MV , class OP >
int Belos::PseudoBlockGmresIter< ScalarType, MV, OP >::getMaxSubspaceDim ( ) const [inline]

Get the maximum dimension allocated for the search subspace.

Definition at line 309 of file BelosPseudoBlockGmresIter.hpp.

template<class ScalarType , class MV , class OP >
const LinearProblem<ScalarType,MV,OP>& Belos::PseudoBlockGmresIter< ScalarType, MV, OP >::getProblem ( ) const [inline, virtual]

Get a constant reference to the linear problem.

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

Definition at line 318 of file BelosPseudoBlockGmresIter.hpp.

template<class ScalarType , class MV , class OP >
int Belos::PseudoBlockGmresIter< 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 321 of file BelosPseudoBlockGmresIter.hpp.

template<class ScalarType , class MV , class OP >
void Belos::PseudoBlockGmresIter< ScalarType, MV, OP >::setBlockSize ( int  blockSize) [inline, virtual]

Set the blocksize.

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

Definition at line 324 of file BelosPseudoBlockGmresIter.hpp.

template<class ScalarType , class MV , class OP >
int Belos::PseudoBlockGmresIter< 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 330 of file BelosPseudoBlockGmresIter.hpp.

template<class ScalarType , class MV , class OP >
void Belos::PseudoBlockGmresIter< ScalarType, MV, OP >::setNumBlocks ( int  numBlocks)

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

Definition at line 425 of file BelosPseudoBlockGmresIter.hpp.

template<class ScalarType , class MV , class OP >
bool Belos::PseudoBlockGmresIter< ScalarType, MV, OP >::isInitialized ( ) [inline, virtual]

States whether the solver has been initialized or not.

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

Definition at line 336 of file BelosPseudoBlockGmresIter.hpp.


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