Dune::InverseOperator2Preconditioner< O, c > Class Template Reference

Turns an InverseOperator into a Preconditioner. More...

#include <dune/istl/preconditioners.hh>

Inheritance diagram for Dune::InverseOperator2Preconditioner< O, c >:

Public Types
typedef O::domain_type	domain_type
	The domain type of the preconditioner.
typedef O::range_type	range_type
	The range type of the preconditioner.
typedef range_type::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
typedef O	InverseOperator
	type of the wrapped inverse operator

Public Member Functions
	InverseOperator2Preconditioner (InverseOperator &inverse_operator)
	Construct the preconditioner from the solver.
virtual void	pre (domain_type &, range_type &)
	Prepare the preconditioner.
virtual void	apply (domain_type &v, const range_type &d)
	Apply one step of the preconditioner to the system A(v)=d.
virtual void	post (domain_type &)
	Clean up.
virtual SolverCategory::Category	category () const
	Category of the preconditioner (see SolverCategory::Category)

Detailed Description

template<class O, int c = -1>
class Dune::InverseOperator2Preconditioner< O, c >

Turns an InverseOperator into a Preconditioner.

Template Parameters

O	The type of the inverse operator to wrap.

Member Typedef Documentation

domain_type

template<class O , int c = -1>

typedef O::domain_type Dune::InverseOperator2Preconditioner< O, c >::domain_type

The domain type of the preconditioner.

field_type

template<class O , int c = -1>

typedef range_type::field_type Dune::InverseOperator2Preconditioner< O, c >::field_type

The field type of the preconditioner.

InverseOperator

template<class O , int c = -1>

typedef O Dune::InverseOperator2Preconditioner< O, c >::InverseOperator

type of the wrapped inverse operator

range_type

template<class O , int c = -1>

typedef O::range_type Dune::InverseOperator2Preconditioner< O, c >::range_type

The range type of the preconditioner.

real_field_type

template<class O , int c = -1>

typedef FieldTraits<scalar_field_type>::real_type Dune::InverseOperator2Preconditioner< O, c >::real_field_type

real scalar type underlying the field_type

scalar_field_type

template<class O , int c = -1>

typedef Simd::Scalar<field_type> Dune::InverseOperator2Preconditioner< O, c >::scalar_field_type

scalar type underlying the field_type

Constructor & Destructor Documentation

InverseOperator2Preconditioner()

template<class O , int c = -1>

Dune::InverseOperator2Preconditioner< O, c >::InverseOperator2Preconditioner ( InverseOperator &  inverse_operator )

inline

Construct the preconditioner from the solver.

Parameters

inverse_operator

The inverse operator to wrap.

Member Function Documentation

apply()

template<class O , int c = -1>

virtual void Dune::InverseOperator2Preconditioner< O, c >::apply ( domain_type &  v, const range_type &  d  )

inlinevirtual

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< O::domain_type, O::range_type >.

category()

template<class O , int c = -1>

virtual SolverCategory::Category Dune::InverseOperator2Preconditioner< O, c >::category ( ) const

inlinevirtual

Category of the preconditioner (see SolverCategory::Category)

Implements Dune::Preconditioner< O::domain_type, O::range_type >.

post()

template<class O , int c = -1>

virtual void Dune::InverseOperator2Preconditioner< O, c >::post ( domain_type &  x )

inlinevirtual

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< O::domain_type, O::range_type >.

pre()

template<class O , int c = -1>

virtual void Dune::InverseOperator2Preconditioner< O, c >::pre ( domain_type &  x, range_type &  b  )

inlinevirtual

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< O::domain_type, O::range_type >.

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

• preconditioners.hh