dune-istl  2.7.1
Public Types | Public Member Functions | Protected Attributes | List of all members
Dune::SeqILU< M, X, Y, l > Class Template Reference

Sequential ILU preconditioner. More...

#include <dune/istl/preconditioners.hh>

Inheritance diagram for Dune::SeqILU< M, X, Y, l >:
Inheritance graph

Public Types

typedef std::remove_const< M >::type matrix_type
 The matrix type the preconditioner is for. More...
 
typedef matrix_type ::block_type block_type
 block type of matrix More...
 
typedef X domain_type
 The domain type of the preconditioner. More...
 
typedef Y range_type
 The range type of the preconditioner. More...
 
typedef X::field_type field_type
 The field type of the preconditioner. More...
 
typedef Simd::Scalar< field_typescalar_field_type
 scalar type underlying the field_type More...
 
typedef ILU::CRS< block_type, typename M::allocator_type > CRS
 type of ILU storage More...
 

Public Member Functions

 SeqILU (const M &A, scalar_field_type w, const bool resort=false)
 Constructor. More...
 
 SeqILU (const M &A, const ParameterTree &config)
 Constructor. More...
 
 SeqILU (const M &A, int n, scalar_field_type w, const bool resort=false)
 Constructor. More...
 
virtual void pre (X &x, Y &b)
 Prepare the preconditioner. More...
 
virtual void apply (X &v, const Y &d)
 Apply the preconditioner. More...
 
virtual void post (X &x)
 Clean up. More...
 
virtual SolverCategory::Category category () const
 Category of the preconditioner (see SolverCategory::Category) More...
 

Protected Attributes

std::unique_ptr< matrix_typeILU_
 The ILU(n) decomposition of the matrix. As storage a BCRSMatrix is used. More...
 
CRS lower_
 The ILU(n) decomposition of the matrix. As storage a CRS structure is used. More...
 
CRS upper_
 
std::vector< block_type, typename matrix_type::allocator_type > inv_
 
const scalar_field_type w_
 The relaxation factor to use. More...
 
const bool wNotIdentity_
 true if w != 1.0 More...
 

Detailed Description

template<class M, class X, class Y, int l = 1>
class Dune::SeqILU< M, X, Y, l >

Sequential ILU preconditioner.

Wraps the naked ISTL generic ILU preconditioner into the solver framework.

Template Parameters
MThe matrix type to operate on
XType of the update
YType of the defect
lIgnored. Just there to have the same number of template arguments as other preconditioners.

Member Typedef Documentation

◆ block_type

template<class M , class X , class Y , int l = 1>
typedef matrix_type :: block_type Dune::SeqILU< M, X, Y, l >::block_type

block type of matrix

◆ CRS

template<class M , class X , class Y , int l = 1>
typedef ILU::CRS< block_type , typename M::allocator_type> Dune::SeqILU< M, X, Y, l >::CRS

type of ILU storage

◆ domain_type

template<class M , class X , class Y , int l = 1>
typedef X Dune::SeqILU< M, X, Y, l >::domain_type

The domain type of the preconditioner.

◆ field_type

template<class M , class X , class Y , int l = 1>
typedef X::field_type Dune::SeqILU< M, X, Y, l >::field_type

The field type of the preconditioner.

◆ matrix_type

template<class M , class X , class Y , int l = 1>
typedef std::remove_const<M>::type Dune::SeqILU< M, X, Y, l >::matrix_type

The matrix type the preconditioner is for.

◆ range_type

template<class M , class X , class Y , int l = 1>
typedef Y Dune::SeqILU< M, X, Y, l >::range_type

The range type of the preconditioner.

◆ scalar_field_type

template<class M , class X , class Y , int l = 1>
typedef Simd::Scalar<field_type> Dune::SeqILU< M, X, Y, l >::scalar_field_type

scalar type underlying the field_type

Constructor & Destructor Documentation

◆ SeqILU() [1/3]

template<class M , class X , class Y , int l = 1>
Dune::SeqILU< M, X, Y, l >::SeqILU ( const M &  A,
scalar_field_type  w,
const bool  resort = false 
)
inline

Constructor.

Constructor invoking ILU(0) gets all parameters to operate the prec.

Parameters
AThe matrix to operate on.
wThe relaxation factor.
resorttrue if a resort of the computed ILU for improved performance should be done.

◆ SeqILU() [2/3]

template<class M , class X , class Y , int l = 1>
Dune::SeqILU< M, X, Y, l >::SeqILU ( const M &  A,
const ParameterTree &  config 
)
inline

Constructor.

Parameters
AThe matrix to operate on.
configurationParameterTree containing preconditioner parameters.
ParameterTree Key Meaning
n The order of the ILU decomposition
relaxation The relaxation factor
resort True if a resort of the computed ILU for improved performance should be done.

See ISTL_Factory for the ParameterTree layout and examples.

◆ SeqILU() [3/3]

template<class M , class X , class Y , int l = 1>
Dune::SeqILU< M, X, Y, l >::SeqILU ( const M &  A,
int  n,
scalar_field_type  w,
const bool  resort = false 
)
inline

Constructor.

Constructor invoking ILU(n).

Parameters
AThe matrix to operate on.
nThe order of the ILU decomposition.
wThe relaxation factor.
resorttrue if a resort of the computed ILU for improved performance should be done.

Member Function Documentation

◆ apply()

template<class M , class X , class Y , int l = 1>
virtual void Dune::SeqILU< M, X, Y, l >::apply ( X &  v,
const Y &  d 
)
inlinevirtual

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]vThe update to be computed
dThe current defect.

Implements Dune::Preconditioner< X, Y >.

◆ category()

template<class M , class X , class Y , int l = 1>
virtual SolverCategory::Category Dune::SeqILU< M, X, Y, l >::category ( ) const
inlinevirtual

Category of the preconditioner (see SolverCategory::Category)

Implements Dune::Preconditioner< X, Y >.

◆ post()

template<class M , class X , class Y , int l = 1>
virtual void Dune::SeqILU< M, X, Y, l >::post ( X &  x)
inlinevirtual

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
xThe right hand side of the equation.

Implements Dune::Preconditioner< X, Y >.

◆ pre()

template<class M , class X , class Y , int l = 1>
virtual void Dune::SeqILU< M, X, Y, l >::pre ( X &  x,
Y &  b 
)
inlinevirtual

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 = ...; // 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
xThe left hand side of the equation.
bThe right hand side of the equation.

Implements Dune::Preconditioner< X, Y >.

Member Data Documentation

◆ ILU_

template<class M , class X , class Y , int l = 1>
std::unique_ptr< matrix_type > Dune::SeqILU< M, X, Y, l >::ILU_
protected

The ILU(n) decomposition of the matrix. As storage a BCRSMatrix is used.

◆ inv_

template<class M , class X , class Y , int l = 1>
std::vector< block_type, typename matrix_type::allocator_type > Dune::SeqILU< M, X, Y, l >::inv_
protected

◆ lower_

template<class M , class X , class Y , int l = 1>
CRS Dune::SeqILU< M, X, Y, l >::lower_
protected

The ILU(n) decomposition of the matrix. As storage a CRS structure is used.

◆ upper_

template<class M , class X , class Y , int l = 1>
CRS Dune::SeqILU< M, X, Y, l >::upper_
protected

◆ w_

template<class M , class X , class Y , int l = 1>
const scalar_field_type Dune::SeqILU< M, X, Y, l >::w_
protected

The relaxation factor to use.

◆ wNotIdentity_

template<class M , class X , class Y , int l = 1>
const bool Dune::SeqILU< M, X, Y, l >::wNotIdentity_
protected

true if w != 1.0


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