Richardson preconditioner.
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#include <dune/istl/preconditioners.hh>
template<class X, class Y>
class Dune::Richardson< X, Y >
Richardson preconditioner.
Multiply simply by a constant.
- Template Parameters
-
X | Type of the update |
Y | Type of the defect |
◆ domain_type
template<class X , class Y >
The domain type of the preconditioner.
◆ field_type
template<class X , class Y >
The field type of the preconditioner.
◆ range_type
template<class X , class Y >
The range type of the preconditioner.
◆ scalar_field_type
template<class X , class Y >
scalar type underlying the field_type
◆ Richardson() [1/2]
template<class X , class Y >
Constructor.
Constructor gets all parameters to operate the prec.
- Parameters
-
◆ Richardson() [2/2]
template<class X , class Y >
Constructor.
- Parameters
-
configuration | ParameterTree containing preconditioner parameters. |
ParameterTree Key | Meaning |
relaxation | The relaxation factor |
See ISTL_Factory for the ParameterTree layout and examples.
◆ apply()
template<class X , class Y >
Apply the precondioner.
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
where
is the approximate inverse of the operator
characterizing the preconditioner.
- Parameters
-
[out] | v | The update to be computed |
| d | The current defect. |
Implements Dune::Preconditioner< X, Y >.
◆ category()
template<class X , class Y >
◆ post()
template<class X , class Y >
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 X , class Y >
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 mangement.
X x(0.0);
Y b = ...;
Preconditioner<X,Y> prec(...);
prec.pre(x,b);
prec.apply(x,b);
prec.post(x);
- Parameters
-
x | The left hand side of the equation. |
b | The right hand side of the equation. |
Implements Dune::Preconditioner< X, Y >.
The documentation for this class was generated from the following file: