Sequential ILU(n) preconditioner.
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#include <dune/istl/preconditioners.hh>
template<class M, class X, class Y, int l = 1>
class Dune::SeqILUn< M, X, Y, l >
Sequential ILU(n) preconditioner.
Wraps the naked ISTL generic ILU(n) 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 | Ignored. Just there to have the same number of template arguments as other preconditioners. |
- Deprecated:
- Use SeqILU instead!
◆ domain_type
template<class M , class X , class Y , int l = 1>
The domain type of the preconditioner.
◆ field_type
template<class M , class X , class Y , int l = 1>
The field type of the preconditioner.
◆ matrix_type
template<class M , class X , class Y , int l = 1>
The matrix type the preconditioner is for.
◆ range_type
template<class M , class X , class Y , int l = 1>
The range type of the preconditioner.
◆ scalar_field_type
template<class M , class X , class Y , int l = 1>
scalar type underlying the field_type
◆ SeqILUn() [1/2]
template<class M , class X , class Y , int l = 1>
Constructor.
Constructor gets all parameters to operate the prec.
- Parameters
-
A | The matrix to operate on. |
n | The order of the ILU decomposition. |
w | The relaxation factor. |
◆ SeqILUn() [2/2]
template<class M , class X , class Y , int l = 1>
Constructor.
- Parameters
-
A | The matrix to operate on. |
configuration | ParameterTree containing preconditioner parameters. |
ParameterTree Key | Meaning |
iterations | The number of iterations to perform |
relaxation | The relaxation factor |
See ISTL_Factory for the ParameterTree layout and examples.
◆ apply()
template<class M , class X , class Y , int l = 1>
virtual void Dune::SeqILUn< M, X, Y, l >::apply |
( |
X & |
v, |
|
|
const Y & |
d |
|
) |
| |
|
inlinevirtual |
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 M , class X , class Y , int l = 1>
◆ post()
template<class M , class X , class Y , int l = 1>
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>
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: