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A numerical linear algebra library targeting many-core architectures
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gko::preconditioner::Ilu< LSolverType, USolverType, 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>

Collaboration diagram for gko::preconditioner::Ilu< LSolverType, USolverType, ReverseApply, IndexType >:
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Classes

class  Factory
 
struct  parameters_type
 

Public Types

using value_type = typename LSolverType::value_type
 
using l_solver_type = LSolverType
 
using u_solver_type = USolverType
 
using index_type = IndexType
 
using transposed_type = Ilu< typename USolverType::transposed_type, typename LSolverType::transposed_type, ReverseApply, IndexType >
 
- Public Types inherited from gko::EnablePolymorphicAssignment< Ilu< LSolverType, USolverType, ReverseApply, IndexType > >
using result_type = Ilu< LSolverType, USolverType, ReverseApply, IndexType >
 
- Public Types inherited from gko::ConvertibleTo< Ilu< LSolverType, USolverType, ReverseApply, IndexType > >
using result_type = Ilu< LSolverType, USolverType, ReverseApply, IndexType >
 

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. More...
 
std::shared_ptr< const u_solver_type > get_u_solver () const
 Returns the solver which is used for the provided U matrix. More...
 
std::unique_ptr< LinOptranspose () const override
 Returns a LinOp representing the transpose of the Transposable object. More...
 
std::unique_ptr< LinOpconj_transpose () const override
 Returns a LinOp representing the conjugate transpose of the Transposable object. More...
 
- Public Member Functions inherited from gko::EnableLinOp< Ilu< LSolverType, USolverType, ReverseApply, IndexType > >
const Ilu< LSolverType, USolverType, ReverseApply, IndexType > * apply (const LinOp *b, LinOp *x) const
 
Ilu< LSolverType, USolverType, ReverseApply, IndexType > * apply (const LinOp *b, LinOp *x)
 
const Ilu< LSolverType, USolverType, ReverseApply, IndexType > * apply (const LinOp *alpha, const LinOp *b, const LinOp *beta, LinOp *x) const
 
Ilu< LSolverType, USolverType, ReverseApply, IndexType > * apply (const LinOp *alpha, const LinOp *b, const LinOp *beta, LinOp *x)
 
- Public Member Functions inherited from gko::EnableAbstractPolymorphicObject< Ilu< LSolverType, USolverType, ReverseApply, IndexType >, LinOp >
std::unique_ptr< Ilu< LSolverType, USolverType, ReverseApply, IndexType > > create_default (std::shared_ptr< const Executor > exec) const
 
std::unique_ptr< Ilu< LSolverType, USolverType, ReverseApply, IndexType > > create_default () const
 
std::unique_ptr< Ilu< LSolverType, USolverType, ReverseApply, IndexType > > clone (std::shared_ptr< const Executor > exec) const
 
std::unique_ptr< Ilu< LSolverType, USolverType, ReverseApply, IndexType > > clone () const
 
Ilu< LSolverType, USolverType, ReverseApply, IndexType > * copy_from (const PolymorphicObject *other)
 
Ilu< LSolverType, USolverType, ReverseApply, IndexType > * copy_from (std::unique_ptr< PolymorphicObject > other)
 
Ilu< LSolverType, USolverType, ReverseApply, IndexType > * clear ()
 
- Public Member Functions inherited from gko::LinOp
LinOpapply (const LinOp *b, LinOp *x)
 Applies a linear operator to a vector (or a sequence of vectors). More...
 
const LinOpapply (const LinOp *b, LinOp *x) const
 Applies a linear operator to a vector (or a sequence of vectors). More...
 
LinOpapply (const LinOp *alpha, const LinOp *b, const LinOp *beta, LinOp *x)
 Performs the operation x = alpha * op(b) + beta * x. More...
 
const LinOpapply (const LinOp *alpha, const LinOp *b, const LinOp *beta, LinOp *x) const
 Performs the operation x = alpha * op(b) + beta * x. More...
 
const dim< 2 > & get_size () const noexcept
 Returns the size of the operator. More...
 
virtual bool apply_uses_initial_guess () const
 Returns true if the linear operator uses the data given in x as an initial guess. More...
 
- Public Member Functions inherited from gko::EnableAbstractPolymorphicObject< LinOp >
std::unique_ptr< LinOpcreate_default (std::shared_ptr< const Executor > exec) const
 
std::unique_ptr< LinOpcreate_default () const
 
std::unique_ptr< LinOpclone (std::shared_ptr< const Executor > exec) const
 
std::unique_ptr< LinOpclone () const
 
LinOpcopy_from (const PolymorphicObject *other)
 
LinOpcopy_from (std::unique_ptr< PolymorphicObject > other)
 
LinOpclear ()
 
- Public Member Functions inherited from gko::PolymorphicObject
PolymorphicObjectoperator= (const PolymorphicObject &)
 
std::unique_ptr< PolymorphicObjectcreate_default (std::shared_ptr< const Executor > exec) const
 Creates a new "default" object of the same dynamic type as this object. More...
 
std::unique_ptr< PolymorphicObjectcreate_default () const
 Creates a new "default" object of the same dynamic type as this object. More...
 
std::unique_ptr< PolymorphicObjectclone (std::shared_ptr< const Executor > exec) const
 Creates a clone of the object. More...
 
std::unique_ptr< PolymorphicObjectclone () const
 Creates a clone of the object. More...
 
PolymorphicObjectcopy_from (const PolymorphicObject *other)
 Copies another object into this object. More...
 
PolymorphicObjectcopy_from (std::unique_ptr< PolymorphicObject > other)
 Moves another object into this object. More...
 
PolymorphicObjectclear ()
 Transforms the object into its default state. More...
 
std::shared_ptr< const Executorget_executor () const noexcept
 Returns the Executor of the object. More...
 
- Public Member Functions inherited from gko::log::EnableLogging< PolymorphicObject >
void add_logger (std::shared_ptr< const Logger > logger) override
 Adds a new logger to the list of subscribed loggers. More...
 
void remove_logger (const Logger *logger) override
 Removes a logger from the list of subscribed loggers. More...
 
- Public Member Functions inherited from gko::EnablePolymorphicAssignment< Ilu< LSolverType, USolverType, ReverseApply, IndexType > >
void convert_to (result_type *result) const override
 Converts the implementer to an object of type result_type. More...
 
void move_to (result_type *result) override
 Converts the implementer to an object of type result_type by moving data from this object. More...
 

Static Public Member Functions

static auto build () -> decltype(Factory ::create())
 

Static Public Attributes

static constexpr bool performs_reverse_apply = ReverseApply
 

Friends

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

Detailed Description

template<typename LSolverType = solver::LowerTrs<>, typename USolverType = solver::UpperTrs<>, bool ReverseApply = false, typename IndexType = int32>
class gko::preconditioner::Ilu< LSolverType, USolverType, 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_factory and with_u_solver_factory) 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:

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.
Template Parameters
LSolverTypetype of the solver used for the L matrix. Defaults to solver::LowerTrs
USolverTypetype of the solver 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 Function Documentation

◆ conj_transpose()

template<typename LSolverType = solver::LowerTrs<>, typename USolverType = solver::UpperTrs<>, bool ReverseApply = false, typename IndexType = int32>
std::unique_ptr<LinOp> gko::preconditioner::Ilu< LSolverType, USolverType, ReverseApply, IndexType >::conj_transpose ( ) const
inlineoverridevirtual

◆ get_l_solver()

template<typename LSolverType = solver::LowerTrs<>, typename USolverType = solver::UpperTrs<>, bool ReverseApply = false, typename IndexType = int32>
std::shared_ptr<const l_solver_type> gko::preconditioner::Ilu< LSolverType, USolverType, 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 gko::preconditioner::Ilu< LSolverType, USolverType, ReverseApply, IndexType >::conj_transpose(), and gko::preconditioner::Ilu< LSolverType, USolverType, ReverseApply, IndexType >::transpose().

◆ get_u_solver()

template<typename LSolverType = solver::LowerTrs<>, typename USolverType = solver::UpperTrs<>, bool ReverseApply = false, typename IndexType = int32>
std::shared_ptr<const u_solver_type> gko::preconditioner::Ilu< LSolverType, USolverType, 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 gko::preconditioner::Ilu< LSolverType, USolverType, ReverseApply, IndexType >::conj_transpose(), and gko::preconditioner::Ilu< LSolverType, USolverType, ReverseApply, IndexType >::transpose().

◆ transpose()

template<typename LSolverType = solver::LowerTrs<>, typename USolverType = solver::UpperTrs<>, bool ReverseApply = false, typename IndexType = int32>
std::unique_ptr<LinOp> gko::preconditioner::Ilu< LSolverType, USolverType, ReverseApply, IndexType >::transpose ( ) const
inlineoverridevirtual

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