Dune Core Modules (2.9.0)

Accelerated flexible conjugate gradient method. More...

#include <dune/istl/solvers.hh>

Public Types

typedef X domain_type
 Type of the domain of the operator to be inverted.
 
typedef X range_type
 Type of the range of the operator to be inverted.
 
typedef X::field_type field_type
 The field type of the operator.
 
typedef FieldTraits< field_type >::real_type real_type
 The real type of the field type (is the same if using real numbers, but differs for std::complex)
 
typedef Simd::Scalar< real_typescalar_real_type
 scalar type underlying the field_type
 

Public Member Functions

 RestartedFCGSolver (const LinearOperator< X, X > &op, Preconditioner< X, X > &prec, scalar_real_type reduction, int maxit, int verbose, int mmax=10)
 Constructor to initialize a RestartedFCG solver. More...
 
 RestartedFCGSolver (const LinearOperator< X, X > &op, const ScalarProduct< X > &sp, Preconditioner< X, X > &prec, scalar_real_type reduction, int maxit, int verbose, int mmax=10)
 Constructor to initialize a RestartedFCG solver. More...
 
 RestartedFCGSolver (std::shared_ptr< const LinearOperator< X, X >> op, std::shared_ptr< const ScalarProduct< X >> sp, std::shared_ptr< Preconditioner< X, X >> prec, scalar_real_type reduction, int maxit, int verbose, int mmax=10)
 Constructor to initialize a RestartedFCG solver. More...
 
 RestartedFCGSolver (std::shared_ptr< const LinearOperator< X, X >> op, std::shared_ptr< Preconditioner< X, X >> prec, const ParameterTree &config)
 Constructor. More...
 
virtual void apply (X &x, X &b, InverseOperatorResult &res)
 Apply inverse operator. More...
 
virtual void apply (X &x, X &b, double reduction, InverseOperatorResult &res)
 Apply inverse operator with given reduction factor. More...
 
virtual SolverCategory::Category category () const
 Category of the solver (see SolverCategory::Category)
 

Protected Member Functions

void printHeader (std::ostream &s) const
 helper function for printing header of solver output
 
void printOutput (std::ostream &s, const CountType &iter, const DataType &norm, const DataType &norm_old) const
 helper function for printing solver output
 
void printOutput (std::ostream &s, const CountType &iter, const DataType &norm) const
 helper function for printing solver output
 

Detailed Description

template<class X>
class Dune::RestartedFCGSolver< X >

Accelerated flexible conjugate gradient method.

Flexible conjugate gradient method as in Y. Notay 'Flexible conjugate Gradients', SIAM J. Sci. Comput Vol. 22, No.4, pp. 1444-1460

This solver discard cyclic all old directions to speed up computing. In exact arithmetic it is exactly the same as the GeneralizedPCGSolver, but it is much faster, depending on the operator and dimension. On the other hand for large mmax it uses noticeably more memory.

Constructor & Destructor Documentation

◆ RestartedFCGSolver() [1/4]

template<class X >
Dune::RestartedFCGSolver< X >::RestartedFCGSolver ( const LinearOperator< X, X > &  op,
Preconditioner< X, X > &  prec,
scalar_real_type  reduction,
int  maxit,
int  verbose,
int  mmax = 10 
)
inline

Constructor to initialize a RestartedFCG solver.

Parameters
mmaxis the maximal number of previous vectors which are orthogonalized against the new search direction.

◆ RestartedFCGSolver() [2/4]

template<class X >
Dune::RestartedFCGSolver< X >::RestartedFCGSolver ( const LinearOperator< X, X > &  op,
const ScalarProduct< X > &  sp,
Preconditioner< X, X > &  prec,
scalar_real_type  reduction,
int  maxit,
int  verbose,
int  mmax = 10 
)
inline

Constructor to initialize a RestartedFCG solver.

Parameters
mmaxis the maximal number of previous vectors which are orthogonalized against the new search direction.

◆ RestartedFCGSolver() [3/4]

template<class X >
Dune::RestartedFCGSolver< X >::RestartedFCGSolver ( std::shared_ptr< const LinearOperator< X, X >>  op,
std::shared_ptr< const ScalarProduct< X >>  sp,
std::shared_ptr< Preconditioner< X, X >>  prec,
scalar_real_type  reduction,
int  maxit,
int  verbose,
int  mmax = 10 
)
inline

Constructor to initialize a RestartedFCG solver.

Parameters
mmaxis the maximal number of previous vectors which are orthogonalized against the new search direction.

◆ RestartedFCGSolver() [4/4]

template<class X >
Dune::RestartedFCGSolver< X >::RestartedFCGSolver ( std::shared_ptr< const LinearOperator< X, X >>  op,
std::shared_ptr< Preconditioner< X, X >>  prec,
const ParameterTree config 
)
inline

Constructor.

Additional parameter:

ParameterTree Key Meaning
mmax number of FCG cycles before restart. default=10

See ISTL_Factory for the ParameterTree layout and examples.

Member Function Documentation

◆ apply() [1/2]

virtual void Dune::IterativeSolver< X, X >::apply ( X &  x,
X &  b,
double  reduction,
InverseOperatorResult res 
)
inlinevirtualinherited

Apply inverse operator with given reduction factor.

apply inverse operator, with given convergence criteria.

Warning
Right hand side b may be overwritten!
Parameters
xThe left hand side to store the result in.
bThe right hand side
reductionThe minimum defect reduction to achieve.
resObject to store the statistics about applying the operator.
Exceptions
SolverAbortWhen the solver detects a problem and cannot continue

Implements Dune::InverseOperator< X, X >.

◆ apply() [2/2]

template<class X >
virtual void Dune::RestartedFCGSolver< X >::apply ( X &  x,
X &  b,
InverseOperatorResult res 
)
inlinevirtual

Apply inverse operator.

Apply inverse operator,.

Warning
Note: right hand side b may be overwritten!
Parameters
xThe left hand side to store the result in.
bThe right hand side
resObject to store the statistics about applying the operator.
Exceptions
SolverAbortWhen the solver detects a problem and cannot continue
Note
Currently, the RestartedFCGSolver aborts when a NaN or infinite defect is detected. However, -ffinite-math-only (implied by -ffast-math) can inhibit a result from becoming NaN that really should be NaN. E.g. numeric_limits<double>::quiet_NaN()*0.0==0.0 with gcc-5.3 -ffast-math.

Implements Dune::InverseOperator< X, X >.

Reimplemented in Dune::CompleteFCGSolver< X >.

References Dune::InverseOperatorResult::clear(), Dune::InverseOperatorResult::converged, and Dune::Simd::Overloads::min().

Referenced by Dune::CompleteFCGSolver< X >::apply().


The documentation for this class was generated from the following file:
Creative Commons License   |  Legal Statements / Impressum  |  Hosted by TU Dresden  |  generated with Hugo v0.80.0 (May 27, 22:31, 2024)