Dune::SeqSOR< M, X, Y, l > Class Template Reference

Sequential SOR preconditioner. More...

#include <dune/istl/preconditioners.hh>

Public Types
typedef M	matrix_type
	The matrix type the preconditioner is for.
typedef X	domain_type
	The domain type of the preconditioner.
typedef Y	range_type
	The range type of the preconditioner.
typedef X::field_type	field_type
	The field type of the preconditioner.
typedef Simd::Scalar< field_type >	scalar_field_type
	scalar type underlying the field_type
typedef FieldTraits< scalar_field_type >::real_type	real_field_type
	real scalar type underlying the field_type

Public Member Functions
	SeqSOR (const M &A, int n, real_field_type w)
	Constructor. More...
	SeqSOR (const std::shared_ptr< const AssembledLinearOperator< M, X, Y > > &A, const ParameterTree &configuration)
	Constructor. More...
	SeqSOR (const M &A, const ParameterTree &configuration)
	Constructor. More...
void	pre (X &x, Y &b) override
	Prepare the preconditioner. More...
void	apply (X &v, const Y &d) override
	Apply the preconditioner. More...
template<bool forward>
void	apply (X &v, const Y &d)
	Apply the preconditioner in a special direction. More...
void	post (X &x) override
	Clean up. More...
SolverCategory::Category	category () const override
	Category of the preconditioner (see SolverCategory::Category)

Detailed Description

template<class M, class X, class Y, int l = 1>
class Dune::SeqSOR< M, X, Y, l >

Sequential SOR preconditioner.

Wraps the naked ISTL generic SOR preconditioner into the solver framework.

Template Parameters

M	The matrix type to operate on
X	Type of the update
Y	Type of the defect
l	The block level to invert. Default is 1

Constructor & Destructor Documentation

SeqSOR() [1/3]

template<class M , class X , class Y , int l = 1>

Dune::SeqSOR< M, X, Y, l >::SeqSOR ( const M &  A, int  n, real_field_type  w  )

inline

Constructor.

constructor gets all parameters to operate the prec.

Parameters

A	The matrix to operate on.
n	The number of iterations to perform.
w	The relaxation factor.

SeqSOR() [2/3]

template<class M , class X , class Y , int l = 1>

Dune::SeqSOR< M, X, Y, l >::SeqSOR ( const std::shared_ptr< const AssembledLinearOperator< M, X, Y > > &  A, const ParameterTree &  configuration  )

inline

Constructor.

Parameters

A	The assembled linear operator to use.
configuration	ParameterTree containing preconditioner parameters.

ParameterTree Key	Meaning
iterations	The number of iterations to perform. default=1
relaxation	The relaxation factor. default=1.0

See ISTL_Factory for the ParameterTree layout and examples.

SeqSOR() [3/3]

template<class M , class X , class Y , int l = 1>

Dune::SeqSOR< M, X, Y, l >::SeqSOR ( const M &  A, const ParameterTree &  configuration  )

inline

Constructor.

Parameters

A	The matrix to operate on.
configuration	ParameterTree containing preconditioner parameters.

ParameterTree Key	Meaning
iterations	The number of iterations to perform. default=1
relaxation	The relaxation factor. default=1.0

See ISTL_Factory for the ParameterTree layout and examples.

Member Function Documentation

apply() [1/2]

template<class M , class X , class Y , int l = 1>

template<bool forward>

void Dune::SeqSOR< M, X, Y, l >::apply ( X &  v, const Y &  d  )

inlinevirtual

Apply the preconditioner in a special direction.

The template parameter forward indications the direction the smoother is applied. If true The application is started at the lowest index in the vector v, if false at the highest index of vector v.

Implements Dune::Preconditioner< X, Y >.

References Dune::bsorb(), and Dune::bsorf().

apply() [2/2]

template<class M , class X , class Y , int l = 1>

void Dune::SeqSOR< M, X, Y, l >::apply ( X &  v, const Y &  d  )

inlineoverridevirtual

Apply the preconditioner.

Apply one step of the preconditioner to the system A(v)=d.

On entry v=0 and d=b-A(x) (although this might not be computed in that way. On exit v contains the update, i.e one step computes \( v = M^{-1} d \) where \( M \) is the approximate inverse of the operator \( A \) characterizing the preconditioner.

Parameters

[out]	v	The update to be computed
	d	The current defect.

Implements Dune::Preconditioner< X, Y >.

post()

template<class M , class X , class Y , int l = 1>

void Dune::SeqSOR< M, X, Y, l >::post ( X &  x )

inlineoverridevirtual

Clean up.

Clean up.

This method is called after the last apply call for the linear system to be solved. Memory may be deallocated safely here. x is the solution of the linear equation.

Parameters

x	The right hand side of the equation.

Implements Dune::Preconditioner< X, Y >.

pre()

template<class M , class X , class Y , int l = 1>

void Dune::SeqSOR< M, X, Y, l >::pre ( X &  x, Y &  b  )

inlineoverridevirtual

Prepare the preconditioner.

Prepare the preconditioner.

A solver solves a linear operator equation A(x)=b by applying one or several steps of the preconditioner. The method pre() is called before the first apply operation. b and x are right hand side and solution vector of the linear system respectively. It may. e.g., scale the system, allocate memory or compute a (I)LU decomposition. Note: The ILU decomposition could also be computed in the constructor or with a separate method of the derived method if several linear systems with the same matrix are to be solved.

Note

if a preconditioner is copied (e.g. for a second thread) again the pre() method has to be called to ensure proper memory management.

X x(0.0);
Y b = ...; // rhs
Preconditioner<X,Y> prec(...);
prec.pre(x,b);   // prepare the preconditioner
prec.apply(x,b); // can be called multiple times now...
prec.post(x);    // cleanup internal state

Parameters

x	The left hand side of the equation.
b	The right hand side of the equation.

Implements Dune::Preconditioner< X, Y >.

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

• dune/istl/preconditioners.hh