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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 >:
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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. More...
 
virtual ~BlockFGmresIter ()
 Destructor. More...
 
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). 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...
 
State methods
Status methods
Accessor methods
- Public Member Functions inherited from Belos::Iteration< ScalarType, MV, OP >
 Iteration ()
 Default Constructor. More...
 
virtual ~Iteration ()
 Destructor. More...
 
virtual Teuchos::RCP< const MV > getNativeResiduals (std::vector< typename Teuchos::ScalarTraits< ScalarType >::magnitudeType > *norms) const =0
 Get the residuals native to the solver. More...
 

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 51 of file BelosBlockFGmresIter.hpp.

Member Typedef Documentation

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

Definition at line 58 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 59 of file BelosBlockFGmresIter.hpp.

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

Definition at line 60 of file BelosBlockFGmresIter.hpp.

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

Definition at line 61 of file BelosBlockFGmresIter.hpp.

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 302 of file BelosBlockFGmresIter.hpp.

template<class ScalarType , class MV , class OP >
virtual Belos::BlockFGmresIter< ScalarType, MV, OP >::~BlockFGmresIter ( )
inlinevirtual

Destructor.

Definition at line 82 of file BelosBlockFGmresIter.hpp.

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 613 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 517 of file BelosBlockFGmresIter.hpp.

template<class ScalarType , class MV , class OP >
void Belos::BlockFGmresIter< 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 138 of file BelosBlockFGmresIter.hpp.

template<class ScalarType , class MV , class OP >
GmresIterationState<ScalarType,MV> Belos::BlockFGmresIter< 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 151 of file BelosBlockFGmresIter.hpp.

template<class ScalarType , class MV , class OP >
int Belos::BlockFGmresIter< ScalarType, MV, OP >::getNumIters ( ) const
inlinevirtual

Get the current iteration count.

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

Definition at line 169 of file BelosBlockFGmresIter.hpp.

template<class ScalarType , class MV , class OP >
void Belos::BlockFGmresIter< ScalarType, MV, OP >::resetNumIters ( int  iter = 0)
inlinevirtual

Reset the iteration count.

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

Definition at line 172 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 496 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 456 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 701 of file BelosBlockFGmresIter.hpp.

template<class ScalarType , class MV , class OP >
int Belos::BlockFGmresIter< 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 BelosBlockFGmresIter.hpp.

template<class ScalarType , class MV , class OP >
int Belos::BlockFGmresIter< 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 BelosBlockFGmresIter.hpp.

template<class ScalarType , class MV , class OP >
const LinearProblem<ScalarType,MV,OP>& Belos::BlockFGmresIter< 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 BelosBlockFGmresIter.hpp.

template<class ScalarType , class MV , class OP >
int Belos::BlockFGmresIter< 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 BelosBlockFGmresIter.hpp.

template<class ScalarType , class MV , class OP >
void Belos::BlockFGmresIter< ScalarType, MV, OP >::setBlockSize ( int  blockSize)
inlinevirtual

Set the blocksize.

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

Definition at line 214 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 217 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 220 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 332 of file BelosBlockFGmresIter.hpp.

template<class ScalarType , class MV , class OP >
bool Belos::BlockFGmresIter< 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 BelosBlockFGmresIter.hpp.


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

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