Dune Core Modules (2.9.0)

Base class for matrix free definition of preconditioners. More...

#include <dune/istl/preconditioner.hh>

Public Types

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.

Public Member Functions

virtual void pre (X &x, Y &b)=0
 Prepare the preconditioner. More...
virtual void apply (X &v, const Y &d)=0
 Apply one step of the preconditioner to the system A(v)=d. More...
virtual void post (X &x)=0
 Clean up. More...
virtual SolverCategory::Category category () const =0
 Category of the preconditioner (see SolverCategory::Category)
virtual ~Preconditioner ()
 every abstract base class has a virtual destructor

Detailed Description

template<class X, class Y>
class Dune::Preconditioner< X, Y >

Base class for matrix free definition of preconditioners.

Note that the operator, which is the basis for the preconditioning, is supplied to the preconditioner from the outside in the constructor or some other method.

This interface allows the encapsulation of all parallelization aspects into the preconditioners.

Template Parameters
XType of the update
YType of the defect

Member Function Documentation

◆ apply()

◆ post()

◆ pre()

template<class X , class Y >
virtual void Dune::Preconditioner< X, Y >::pre ( X &  x,
Y &  b 
pure virtual

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.

if a preconditioner is copied (e.g. for a second thread) again the pre() method has to be called to ensure proper memory mangement.
X x(0.0);
Y b = ...; // rhs
prec.pre(x,b); // prepare the preconditioner
prec.apply(x,b); // can be called multiple times now...
prec.post(x); // cleanup internal state
Base class for matrix free definition of preconditioners.
Definition: preconditioner.hh:32
xThe left hand side of the equation.
bThe right hand side of the equation.

Implemented in Dune::Amg::AMG< M, X, S, PI, A >, Dune::Amg::AMG< M, X, S, SequentialInformation, std::allocator< X > >, Dune::Amg::AMG< Operator, X, Smoother >, Dune::Amg::FastAMG< M, X, PI, A >, Dune::Amg::KAMG< M, X, S, PI, K, A >, Dune::InverseOperator2Preconditioner< O, c >, Dune::NonoverlappingBlockPreconditioner< C, P >, Dune::SeqOverlappingSchwarz< M, X, TM, TD, TA >, Dune::SeqOverlappingSchwarz< M, X, TM, TS, TA >, Dune::SeqSSOR< M, X, Y, l >, Dune::SeqSOR< M, X, Y, l >, Dune::SeqJac< M, X, Y, l >, Dune::SeqILU< M, X, Y, l >, Dune::Richardson< X, Y >, Dune::ParSSOR< M, X, Y, C >, Dune::BlockPreconditioner< X, Y, C, P >, and Dune::SeqILDL< M, X, Y >.

The documentation for this class was generated from the following file:
Creative Commons License   |  Legal Statements / Impressum  |  Hosted by TU Dresden  |  generated with Hugo v0.111.3 (Jun 16, 22:32, 2024)