Ginkgo Generated from branch based on main. Ginkgo version 1.10.0
A numerical linear algebra library targeting many-core architectures
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gko::preconditioner::Ilu< LSolverTypeOrValueType, USolverTypeOrValueType, ReverseApply, IndexType > Class Template Reference

The Incomplete LU (ILU) preconditioner solves the equation $LUx = b$ for a given lower triangular matrix L, an upper triangular matrix U and the right hand side b (can contain multiple right hand sides). More...

#include <ginkgo/core/preconditioner/ilu.hpp>

Inheritance diagram for gko::preconditioner::Ilu< LSolverTypeOrValueType, USolverTypeOrValueType, ReverseApply, IndexType >:
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Collaboration diagram for gko::preconditioner::Ilu< LSolverTypeOrValueType, USolverTypeOrValueType, ReverseApply, IndexType >:
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Classes

class  Factory
struct  parameters_type

Public Types

using value_type = gko::detail::get_value_type<LSolverTypeOrValueType>
using l_solver_type
using u_solver_type
using index_type = IndexType
using transposed_type

Public Member Functions

const parameters_typeget_parameters () const
std::shared_ptr< const l_solver_type > get_l_solver () const
 Returns the solver which is used for the provided L matrix.
std::shared_ptr< const u_solver_type > get_u_solver () const
 Returns the solver which is used for the provided U matrix.
std::unique_ptr< LinOptranspose () const override
 Returns a LinOp representing the transpose of the Transposable object.
std::unique_ptr< LinOpconj_transpose () const override
 Returns a LinOp representing the conjugate transpose of the Transposable object.
Iluoperator= (const Ilu &other)
 Copy-assigns an ILU preconditioner.
Iluoperator= (Ilu &&other)
 Move-assigns an ILU preconditioner.
 Ilu (const Ilu &other)
 Copy-constructs an ILU preconditioner.
 Ilu (Ilu &&other)
 Move-constructs an ILU preconditioner.

Static Public Member Functions

static auto build () -> decltype(Factory::create())
static parameters_type parse (const config::pnode &config, const config::registry &context, const config::type_descriptor &td_for_child=config::make_type_descriptor< value_type, index_type >())
 Create the parameters from the property_tree.

Static Public Attributes

static constexpr bool performs_reverse_apply = ReverseApply

Friends

class EnableLinOp< Ilu >
class EnablePolymorphicObject< Ilu, LinOp >

Detailed Description

template<typename LSolverTypeOrValueType = solver::LowerTrs<>, typename USolverTypeOrValueType = gko::detail::transposed_type<LSolverTypeOrValueType>, bool ReverseApply = false, typename IndexType = int32>
class gko::preconditioner::Ilu< LSolverTypeOrValueType, USolverTypeOrValueType, ReverseApply, IndexType >

The Incomplete LU (ILU) preconditioner solves the equation $LUx = b$ for a given lower triangular matrix L, an upper triangular matrix U and the right hand side b (can contain multiple right hand sides).

It allows to set both the solver for L and the solver for U independently, while providing the defaults solver::LowerTrs and solver::UpperTrs, which are direct triangular solvers. For these solvers, a factory can be provided (with with_l_solver and with_u_solver) to have more control over their behavior. In particular, it is possible to use an iterative method for solving the triangular systems. The default parameters for an iterative triangluar solver are:

  • reduction factor = 1e-4
  • max iteration = <number of rows of the matrix given to the solver> Solvers without such criteria can also be used, in which case none are set.

An object of this class can be created with a matrix or a gko::Composition containing two matrices. If created with a matrix, it is factorized before creating the solver. If a gko::Composition (containing two matrices) is used, the first operand will be taken as the L matrix, the second will be considered the U matrix. ParIlu can be directly used, since it orders the factors in the correct way.

Note
When providing a gko::Composition, the first matrix must be the lower matrix ( $L$), and the second matrix must be the upper matrix ( $U$). If they are swapped, solving might crash or return the wrong result.
Do not use symmetric solvers (like CG) for L or U solvers since both matrices (L and U) are, by design, not symmetric.
This class is not thread safe (even a const object is not) because it uses an internal cache to accelerate multiple (sequential) applies. Using it in parallel can lead to segmentation faults, wrong results and other unwanted behavior.
The default template during parse is <ValueType, IndexType> not <LowerTrs, IndexType>. Only the variants with ValueType are supported in parse.
Template Parameters
LSolverTypeOrValueTypetype of the solver or the value type used for the L matrix. Defaults to solver::LowerTrs
USolverTypeOrValueTypetype of the solver or the value type used for the U matrix Defaults to solver::UpperTrs
ReverseApplydefault behavior (ReverseApply = false) is first to solve with L (Ly = b) and then with U (Ux = y). When set to true, it will solve first with U, and then with L.
IndexTypeParIluType of the indices when ParIlu is used to generate both L and U factors. Irrelevant otherwise.

Member Typedef Documentation

◆ l_solver_type

template<typename LSolverTypeOrValueType = solver::LowerTrs<>, typename USolverTypeOrValueType = gko::detail::transposed_type<LSolverTypeOrValueType>, bool ReverseApply = false, typename IndexType = int32>
using gko::preconditioner::Ilu< LSolverTypeOrValueType, USolverTypeOrValueType, ReverseApply, IndexType >::l_solver_type
Initial value:
std::conditional_t<gko::detail::is_ginkgo_linop<LSolverTypeOrValueType>,
LSolverTypeOrValueType, LinOp>
Definition lin_op.hpp:117

◆ transposed_type

template<typename LSolverTypeOrValueType = solver::LowerTrs<>, typename USolverTypeOrValueType = gko::detail::transposed_type<LSolverTypeOrValueType>, bool ReverseApply = false, typename IndexType = int32>
using gko::preconditioner::Ilu< LSolverTypeOrValueType, USolverTypeOrValueType, ReverseApply, IndexType >::transposed_type
Initial value:
gko::detail::transposed_type<LSolverTypeOrValueType>, ReverseApply,
IndexType>
Ilu(const Ilu &other)
Copy-constructs an ILU preconditioner.
Definition ilu.hpp:380

◆ u_solver_type

template<typename LSolverTypeOrValueType = solver::LowerTrs<>, typename USolverTypeOrValueType = gko::detail::transposed_type<LSolverTypeOrValueType>, bool ReverseApply = false, typename IndexType = int32>
using gko::preconditioner::Ilu< LSolverTypeOrValueType, USolverTypeOrValueType, ReverseApply, IndexType >::u_solver_type
Initial value:
std::conditional_t<gko::detail::is_ginkgo_linop<USolverTypeOrValueType>,
USolverTypeOrValueType, LinOp>

Constructor & Destructor Documentation

◆ Ilu() [1/2]

template<typename LSolverTypeOrValueType = solver::LowerTrs<>, typename USolverTypeOrValueType = gko::detail::transposed_type<LSolverTypeOrValueType>, bool ReverseApply = false, typename IndexType = int32>
gko::preconditioner::Ilu< LSolverTypeOrValueType, USolverTypeOrValueType, ReverseApply, IndexType >::Ilu ( const Ilu< LSolverTypeOrValueType, USolverTypeOrValueType, ReverseApply, IndexType > & other)
inline

Copy-constructs an ILU preconditioner.

Inherits the executor, shallow-copies the solvers and parameters.

References Ilu().

Referenced by Ilu(), Ilu(), operator=(), and operator=().

◆ Ilu() [2/2]

template<typename LSolverTypeOrValueType = solver::LowerTrs<>, typename USolverTypeOrValueType = gko::detail::transposed_type<LSolverTypeOrValueType>, bool ReverseApply = false, typename IndexType = int32>
gko::preconditioner::Ilu< LSolverTypeOrValueType, USolverTypeOrValueType, ReverseApply, IndexType >::Ilu ( Ilu< LSolverTypeOrValueType, USolverTypeOrValueType, ReverseApply, IndexType > && other)
inline

Move-constructs an ILU preconditioner.

Inherits the executor, moves the solvers and parameters. The moved-from object is empty (0x0 with nullptr solvers and default parameters)

References Ilu().

Member Function Documentation

◆ conj_transpose()

template<typename LSolverTypeOrValueType = solver::LowerTrs<>, typename USolverTypeOrValueType = gko::detail::transposed_type<LSolverTypeOrValueType>, bool ReverseApply = false, typename IndexType = int32>
std::unique_ptr< LinOp > gko::preconditioner::Ilu< LSolverTypeOrValueType, USolverTypeOrValueType, ReverseApply, IndexType >::conj_transpose ( ) const
inlineoverridevirtual

Returns a LinOp representing the conjugate transpose of the Transposable object.

Returns
a pointer to the new conjugate transposed object

Implements gko::Transposable.

References gko::as(), conj_transpose(), get_l_solver(), get_u_solver(), gko::share(), and gko::transpose().

Referenced by conj_transpose().

◆ get_l_solver()

template<typename LSolverTypeOrValueType = solver::LowerTrs<>, typename USolverTypeOrValueType = gko::detail::transposed_type<LSolverTypeOrValueType>, bool ReverseApply = false, typename IndexType = int32>
std::shared_ptr< const l_solver_type > gko::preconditioner::Ilu< LSolverTypeOrValueType, USolverTypeOrValueType, ReverseApply, IndexType >::get_l_solver ( ) const
inline

Returns the solver which is used for the provided L matrix.

Returns
the solver which is used for the provided L matrix

Referenced by conj_transpose(), and transpose().

◆ get_u_solver()

template<typename LSolverTypeOrValueType = solver::LowerTrs<>, typename USolverTypeOrValueType = gko::detail::transposed_type<LSolverTypeOrValueType>, bool ReverseApply = false, typename IndexType = int32>
std::shared_ptr< const u_solver_type > gko::preconditioner::Ilu< LSolverTypeOrValueType, USolverTypeOrValueType, ReverseApply, IndexType >::get_u_solver ( ) const
inline

Returns the solver which is used for the provided U matrix.

Returns
the solver which is used for the provided U matrix

Referenced by conj_transpose(), and transpose().

◆ operator=() [1/2]

template<typename LSolverTypeOrValueType = solver::LowerTrs<>, typename USolverTypeOrValueType = gko::detail::transposed_type<LSolverTypeOrValueType>, bool ReverseApply = false, typename IndexType = int32>
Ilu & gko::preconditioner::Ilu< LSolverTypeOrValueType, USolverTypeOrValueType, ReverseApply, IndexType >::operator= ( const Ilu< LSolverTypeOrValueType, USolverTypeOrValueType, ReverseApply, IndexType > & other)
inline

Copy-assigns an ILU preconditioner.

Preserves the executor, shallow-copies the solvers and parameters. Creates a clone of the solvers if they are on the wrong executor.

References gko::clone(), Ilu(), and gko::LinOp::operator=().

◆ operator=() [2/2]

template<typename LSolverTypeOrValueType = solver::LowerTrs<>, typename USolverTypeOrValueType = gko::detail::transposed_type<LSolverTypeOrValueType>, bool ReverseApply = false, typename IndexType = int32>
Ilu & gko::preconditioner::Ilu< LSolverTypeOrValueType, USolverTypeOrValueType, ReverseApply, IndexType >::operator= ( Ilu< LSolverTypeOrValueType, USolverTypeOrValueType, ReverseApply, IndexType > && other)
inline

Move-assigns an ILU preconditioner.

Preserves the executor, moves the solvers and parameters. Creates a clone of the solvers if they are on the wrong executor. The moved-from object is empty (0x0 with nullptr solvers and default parameters)

References gko::clone(), Ilu(), and gko::LinOp::operator=().

◆ parse()

template<typename LSolverTypeOrValueType = solver::LowerTrs<>, typename USolverTypeOrValueType = gko::detail::transposed_type<LSolverTypeOrValueType>, bool ReverseApply = false, typename IndexType = int32>
parameters_type gko::preconditioner::Ilu< LSolverTypeOrValueType, USolverTypeOrValueType, ReverseApply, IndexType >::parse ( const config::pnode & config,
const config::registry & context,
const config::type_descriptor & td_for_child = config::make_type_descriptor<value_type, index_type>() )
inlinestatic

Create the parameters from the property_tree.

Because this is directly tied to the specific type, the value/index type settings within config are ignored and type_descriptor is only used for children configs.

Parameters
configthe property tree for setting
contextthe registry
td_for_childthe type descriptor for children configs. The default uses the value/index type of this class.
Returns
parameters
Note
only support the following when using <ValueType, ValueType, ReverseApply, IndexType> not <LSolverType, USolverType, ReverseApply, IndexType> variants

◆ transpose()

template<typename LSolverTypeOrValueType = solver::LowerTrs<>, typename USolverTypeOrValueType = gko::detail::transposed_type<LSolverTypeOrValueType>, bool ReverseApply = false, typename IndexType = int32>
std::unique_ptr< LinOp > gko::preconditioner::Ilu< LSolverTypeOrValueType, USolverTypeOrValueType, ReverseApply, IndexType >::transpose ( ) const
inlineoverridevirtual

Returns a LinOp representing the transpose of the Transposable object.

Returns
a pointer to the new transposed object

Implements gko::Transposable.

References gko::as(), get_l_solver(), get_u_solver(), gko::share(), transpose(), and gko::transpose().

Referenced by transpose().


The documentation for this class was generated from the following file:
  • ginkgo/core/preconditioner/ilu.hpp