Dune::NonoverlappingBlockPreconditioner< C, P > Class Template Reference

Nonoverlapping parallel preconditioner. More...

#include <dune/istl/novlpschwarz.hh>

Public Types
typedef P::domain_type	domain_type
	The domain type of the preconditioner.
typedef P::range_type	range_type
	The range type of the preconditioner.
typedef C	communication_type
	The type of the communication object.
typedef X::field_type	field_type
	The field type of the preconditioner.

Public Member Functions
	NonoverlappingBlockPreconditioner (P &p, const communication_type &c)
	Constructor. More...
	NonoverlappingBlockPreconditioner (const std::shared_ptr< P > &p, const communication_type &c)
	Constructor. More...
void	pre (domain_type &x, range_type &b) override
	Prepare the preconditioner. More...
void	apply (domain_type &v, const range_type &d) override
	Apply the preconditioner. More...
template<bool forward>
void	apply (X &v, const Y &d)
	Apply one step of the preconditioner to the system A(v)=d. More...
void	post (domain_type &x) override
	Clean up. More...
SolverCategory::Category	category () const override
	Category of the preconditioner (see SolverCategory::Category)

Detailed Description

template<class C, class P>
class Dune::NonoverlappingBlockPreconditioner< C, P >

Nonoverlapping parallel preconditioner.

This is essentially a wrapper that takes a sequential preconditioner. In each step the sequential preconditioner is applied and then all owner data points are updated on all other processes.

Constructor & Destructor Documentation

NonoverlappingBlockPreconditioner() [1/2]

template<class C , class P >

Dune::NonoverlappingBlockPreconditioner< C, P >::NonoverlappingBlockPreconditioner ( P &  p, const communication_type &  c  )

inline

Constructor.

constructor gets all parameters to operate the prec.

Parameters

p	The sequential preconditioner.
c	The communication object for syncing overlap and copy data points. (E.~g. OwnerOverlapCopyCommunication )

NonoverlappingBlockPreconditioner() [2/2]

template<class C , class P >

Dune::NonoverlappingBlockPreconditioner< C, P >::NonoverlappingBlockPreconditioner ( const std::shared_ptr< P > &  p, const communication_type &  c  )

inline

Constructor.

constructor gets all parameters to operate the prec.

Parameters

p	The sequential preconditioner.
c	The communication object for syncing overlap and copy data points. (E.~g. OwnerOverlapCopyCommunication )

Member Function Documentation

apply() [1/2]

template<class C , class P >

void Dune::NonoverlappingBlockPreconditioner< C, P >::apply ( domain_type &  v, const range_type &  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< P::domain_type, P::range_type >.

apply() [2/2]

template<class C , class P >

template<bool forward>

void Dune::NonoverlappingBlockPreconditioner< C, P >::apply ( X &  v, const Y &  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< P::domain_type, P::range_type >.

post()

template<class C , class P >

void Dune::NonoverlappingBlockPreconditioner< C, P >::post ( domain_type &  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< P::domain_type, P::range_type >.

pre()

template<class C , class P >

void Dune::NonoverlappingBlockPreconditioner< C, P >::pre ( domain_type &  x, range_type &  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< P::domain_type, P::range_type >.

---

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

• dune/istl/novlpschwarz.hh