Rs implements the Ruge–Stueben (classical) Algebraic Multigrid (AMG) coarsening strategy for M-matrices. More...

#include <ginkgo/core/multigrid/rs.hpp>

Inheritance diagram for gko::multigrid::Rs< ValueType, IndexType >:

Collaboration diagram for gko::multigrid::Rs< ValueType, IndexType >:

Classes
class	Factory

struct	parameters_type

Public Types
using	value_type = ValueType

using	index_type = IndexType

Public Types inherited from gko::EnablePolymorphicAssignment< Rs< ValueType, IndexType > >
using	result_type = Rs< ValueType, IndexType >

Public Types inherited from gko::ConvertibleTo< Rs< ValueType, IndexType > >
using	result_type = Rs< ValueType, IndexType >

Public Types inherited from gko::multigrid::EnableMultigridLevel< ValueType >
using	value_type = ValueType

Public Types inherited from gko::UseComposition< ValueType >
using	value_type = ValueType

Public Member Functions
std::shared_ptr< const LinOp >	get_system_matrix () const
	Returns the system operator (matrix) of the linear system. More...

const parameters_type &	get_parameters () const

Public Member Functions inherited from gko::EnableAbstractPolymorphicObject< Rs< ValueType, IndexType >, LinOp >
std::unique_ptr< Rs< ValueType, IndexType > >	create_default (std::shared_ptr< const Executor > exec) const

std::unique_ptr< Rs< ValueType, IndexType > >	create_default () const

std::unique_ptr< Rs< ValueType, IndexType > >	clone (std::shared_ptr< const Executor > exec) const

std::unique_ptr< Rs< ValueType, IndexType > >	clone () const

Rs< ValueType, IndexType > *	copy_from (const PolymorphicObject *other)

std::enable_if_t< std::is_base_of< PolymorphicObject, std::decay_t< Derived > >::value, Rs< ValueType, IndexType > > *	copy_from (std::unique_ptr< Derived > &&other)

std::enable_if_t< std::is_base_of< PolymorphicObject, std::decay_t< Derived > >::value, Rs< ValueType, IndexType > > *	copy_from (const std::unique_ptr< Derived > &other)

Rs< ValueType, IndexType > *	copy_from (const std::shared_ptr< const PolymorphicObject > &other)

Rs< ValueType, IndexType > *	move_from (ptr_param< PolymorphicObject > other)

Rs< ValueType, IndexType > *	clear ()

Public Member Functions inherited from gko::LinOp
void	apply (ptr_param< const LinOp > b, ptr_param< LinOp > x) const
	Applies a linear operator to a vector (or a sequence of vectors). More...

void	apply (ptr_param< const LinOp > alpha, ptr_param< const LinOp > b, ptr_param< const LinOp > beta, ptr_param< 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...

LinOp &	operator= (const LinOp &)=default
	Copy-assigns a LinOp. More...

LinOp &	operator= (LinOp &&other)
	Move-assigns a LinOp. More...

	LinOp (const LinOp &)=default
	Copy-constructs a LinOp. More...

	LinOp (LinOp &&other)
	Move-constructs a LinOp. More...

Public Member Functions inherited from gko::EnableAbstractPolymorphicObject< LinOp >
std::unique_ptr< LinOp >	create_default (std::shared_ptr< const Executor > exec) const

std::unique_ptr< LinOp >	create_default () const

std::unique_ptr< LinOp >	clone (std::shared_ptr< const Executor > exec) const

std::unique_ptr< LinOp >	clone () const

LinOp *	copy_from (const PolymorphicObject *other)

std::enable_if_t< std::is_base_of< PolymorphicObject, std::decay_t< Derived > >::value, LinOp > *	copy_from (std::unique_ptr< Derived > &&other)

std::enable_if_t< std::is_base_of< PolymorphicObject, std::decay_t< Derived > >::value, LinOp > *	copy_from (const std::unique_ptr< Derived > &other)

LinOp *	copy_from (const std::shared_ptr< const PolymorphicObject > &other)

LinOp *	move_from (ptr_param< PolymorphicObject > other)

LinOp *	clear ()

Public Member Functions inherited from gko::PolymorphicObject
PolymorphicObject &	operator= (const PolymorphicObject &)

std::unique_ptr< PolymorphicObject >	create_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< PolymorphicObject >	create_default () const
	Creates a new "default" object of the same dynamic type as this object. More...

std::unique_ptr< PolymorphicObject >	clone (std::shared_ptr< const Executor > exec) const
	Creates a clone of the object. More...

std::unique_ptr< PolymorphicObject >	clone () const
	Creates a clone of the object. More...

PolymorphicObject *	copy_from (const PolymorphicObject *other)
	Copies another object into this object. More...

template<typename Derived , typename Deleter >
std::enable_if_t< std::is_base_of< PolymorphicObject, std::decay_t< Derived > >::value, PolymorphicObject > *	copy_from (std::unique_ptr< Derived, Deleter > &&other)
	Moves another object into this object. More...

template<typename Derived , typename Deleter >
std::enable_if_t< std::is_base_of< PolymorphicObject, std::decay_t< Derived > >::value, PolymorphicObject > *	copy_from (const std::unique_ptr< Derived, Deleter > &other)
	Copies another object into this object. More...

PolymorphicObject *	copy_from (const std::shared_ptr< const PolymorphicObject > &other)
	Copies another object into this object. More...

PolymorphicObject *	move_from (ptr_param< PolymorphicObject > other)
	Moves another object into this object. More...

PolymorphicObject *	clear ()
	Transforms the object into its default state. More...

std::shared_ptr< const Executor >	get_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

void	remove_logger (const Logger *logger) override

void	remove_logger (ptr_param< const Logger > logger)

const std::vector< std::shared_ptr< const Logger > > &	get_loggers () const override

void	clear_loggers () override

Public Member Functions inherited from gko::log::Loggable
void	remove_logger (ptr_param< const Logger > logger)

Public Member Functions inherited from gko::EnablePolymorphicAssignment< Rs< ValueType, 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...

Public Member Functions inherited from gko::ConvertibleTo< Rs< ValueType, IndexType > >
void	convert_to (ptr_param< result_type > result) const

void	move_to (ptr_param< result_type > result)

Public Member Functions inherited from gko::multigrid::EnableMultigridLevel< ValueType >
std::shared_ptr< const LinOp >	get_fine_op () const override
	Returns the operator on fine level. More...

std::shared_ptr< const LinOp >	get_restrict_op () const override
	Returns the restrict operator. More...

std::shared_ptr< const LinOp >	get_coarse_op () const override
	Returns the operator on coarse level. More...

std::shared_ptr< const LinOp >	get_prolong_op () const override
	Returns the prolong operator. More...

Public Member Functions inherited from gko::UseComposition< ValueType >
std::shared_ptr< Composition< ValueType > >	get_composition () const
	Returns the composition operators. More...

std::shared_ptr< const LinOp >	get_operator_at (size_type index) const
	Returns the operator at index-th position of composition. More...

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< ValueType, IndexType >())

Friends
class	EnableLinOp< Rs >

class	EnablePolymorphicObject< Rs, LinOp >

Detailed Description

template<typename ValueType = default_precision, typename IndexType = int32>
class gko::multigrid::Rs< ValueType, IndexType >

Rs implements the Ruge–Stueben (classical) Algebraic Multigrid (AMG) coarsening strategy for M-matrices.

Given a sparse system $Ax = b$ , it produces one level of an AMG hierarchy: a C/F splitting, a prolongation operator $P$ , and a coarse-grid operator $A_c = R A P$ .

Coarsening proceeds in three steps. First, neighbour $j$ is marked as strongly influencing row $i$ when $-a_{ij} \ge \theta \cdot \max_{k \neq i}(-a_{ik})$ . Second, a greedy pass selects C-points by repeatedly picking the undecided node with the most strong neighbours, marking its undecided strong neighbours as F-points, and updating neighbour counts accordingly. Third, we create the coarse grid and compute the interpolation via the classical RS direct interpolation formula, accounting for both strong C- and F-neighbours.

Ruge, J. W., & Stueben, K. (1987). Algebraic multigrid, Multigrid Methods (Vol. 3, pp. 73–130). Society for Industrial and Applied Mathematics. https://doi.org/10.1137/1.9781611971057.ch4

Template Parameters

ValueType	precision of matrix elements
IndexType	precision of matrix indexes

Member Function Documentation

◆ get_system_matrix()

template<typename ValueType = default_precision, typename IndexType = int32>

std::shared_ptr<const LinOp> gko::multigrid::Rs< ValueType, IndexType >::get_system_matrix ( ) const

inline

Returns the system operator (matrix) of the linear system.

Returns: the system operator (matrix)

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

ginkgo/core/multigrid/rs.hpp

Classes

Public Types

Public Member Functions

Static Public Member Functions

Friends

Detailed Description

template<typename ValueType = default_precision, typename IndexType = int32> class gko::multigrid::Rs< ValueType, IndexType >

Member Function Documentation

◆ get_system_matrix()

template<typename ValueType = default_precision, typename IndexType = int32>
class gko::multigrid::Rs< ValueType, IndexType >