Multigrid methods have a hierarchy of many levels, whose corase level is a subset of the fine level, of the problem. More...

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

Inheritance diagram for gko::solver::Multigrid:

[legend]

Collaboration diagram for gko::solver::Multigrid:

[legend]

Classes
class	Factory

struct	parameters_type

Public Member Functions
bool	apply_uses_initial_guess () const override
	Return true as iterative solvers use the data in x as an initial guess or false if multigrid always set the input as zero. More...

std::vector< std::shared_ptr< const gko::multigrid::MultigridLevel > >	get_mg_level_list () const
	Gets the list of MultigridLevel operators. More...

std::vector< std::shared_ptr< const LinOp > >	get_pre_smoother_list () const
	Gets the list of pre-smoother operators. More...

std::vector< std::shared_ptr< const LinOp > >	get_mid_smoother_list () const
	Gets the list of mid-smoother operators. More...

std::vector< std::shared_ptr< const LinOp > >	get_post_smoother_list () const
	Gets the list of post-smoother operators. More...

std::shared_ptr< const LinOp >	get_coarsest_solver () const
	Gets the operator at the coarsest level. More...

multigrid::cycle	get_cycle () const
	Get the cycle of multigrid. More...

void	set_cycle (multigrid::cycle cycle)
	Set the cycle of multigrid. More...

const parameters_type &	get_parameters () const

Public Member Functions inherited from gko::EnableLinOp< ConcreteLinOp, PolymorphicBase >
const ConcreteLinOp *	apply (ptr_param< const LinOp > b, ptr_param< LinOp > x) const

ConcreteLinOp *	apply (ptr_param< const LinOp > b, ptr_param< LinOp > x)

const ConcreteLinOp *	apply (ptr_param< const LinOp > alpha, ptr_param< const LinOp > b, ptr_param< const LinOp > beta, ptr_param< LinOp > x) const

ConcreteLinOp *	apply (ptr_param< const LinOp > alpha, ptr_param< const LinOp > b, ptr_param< const LinOp > beta, ptr_param< LinOp > x)

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

std::unique_ptr< ConcreteLinOp >	create_default () const

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

std::unique_ptr< ConcreteLinOp >	clone () const

ConcreteLinOp *	copy_from (const PolymorphicObject *other)

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

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

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

ConcreteLinOp *	move_from (ptr_param< PolymorphicObject > other)

ConcreteLinOp *	clear ()

Public Member Functions inherited from gko::EnablePolymorphicAssignment< ConcreteLinOp >
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< ConcreteLinOp >
void	convert_to (ptr_param< result_type > result) const

void	move_to (ptr_param< result_type > result)

Public Member Functions inherited from gko::solver::EnableSolverBase< Multigrid >
EnableSolverBase &	operator= (const EnableSolverBase &other)
	Creates a shallow copy of the provided system matrix, clones it onto this executor if executors don't match.

EnableSolverBase &	operator= (EnableSolverBase &&other)
	Moves the provided system matrix, clones it onto this executor if executors don't match. More...

	EnableSolverBase (std::shared_ptr< const LinOp > system_matrix)

	EnableSolverBase (const EnableSolverBase &other)
	Creates a shallow copy of the provided system matrix.

	EnableSolverBase (EnableSolverBase &&other)
	Moves the provided system matrix. More...

int	get_num_workspace_ops () const override

std::vector< std::string >	get_workspace_op_names () const override

std::vector< int >	get_workspace_scalars () const override
	Returns the IDs of all scalars (workspace vectors with system dimension-independent size, usually 1 x num_rhs).

std::vector< int >	get_workspace_vectors () const override
	Returns the IDs of all vectors (workspace vectors with system dimension-dependent size, usually system_matrix_size x num_rhs).

Public Member Functions inherited from gko::solver::SolverBase< LinOp >
std::shared_ptr< const LinOp >	get_system_matrix () const
	Returns the system matrix, with its concrete type, used by the solver. More...

Public Member Functions inherited from gko::solver::EnableIterativeBase< Multigrid >
EnableIterativeBase &	operator= (const EnableIterativeBase &other)
	Creates a shallow copy of the provided stopping criterion, clones it onto this executor if executors don't match.

EnableIterativeBase &	operator= (EnableIterativeBase &&other)
	Moves the provided stopping criterion, clones it onto this executor if executors don't match. More...

	EnableIterativeBase (std::shared_ptr< const stop::CriterionFactory > stop_factory)

	EnableIterativeBase (const EnableIterativeBase &other)
	Creates a shallow copy of the provided stopping criterion.

	EnableIterativeBase (EnableIterativeBase &&other)
	Moves the provided stopping criterion. More...

void	set_stop_criterion_factory (std::shared_ptr< const stop::CriterionFactory > new_stop_factory) override
	Sets the stopping criterion of the solver. More...

Public Member Functions inherited from gko::solver::IterativeBase
std::shared_ptr< const stop::CriterionFactory >	get_stop_criterion_factory () const
	Gets the stopping criterion factory of the solver. 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<>())
	Create the parameters from the property_tree. More...

Friends
class	EnableLinOp< Multigrid >

class	EnablePolymorphicObject< Multigrid, LinOp >

class	EnableApplyWithInitialGuess< Multigrid >

Additional Inherited Members
Public Types inherited from gko::EnablePolymorphicAssignment< ConcreteLinOp >
using	result_type = ConcreteLinOp

Public Types inherited from gko::ConvertibleTo< ConcreteLinOp >
using	result_type = ConcreteLinOp

Detailed Description

Multigrid methods have a hierarchy of many levels, whose corase level is a subset of the fine level, of the problem.

The coarse level solves the system on the residual of fine level and fine level will use the coarse solution to correct its own result. Multigrid solves the problem by relatively cheap step in each level and refining the result when prolongating back.

The main step of each level

Presmooth (solve on the fine level)
Calculate residual
Restrict (reduce the problem dimension)
Solve residual in next level
Prolongate (return to the fine level size)
Postsmooth (correct the answer in fine level)

Ginkgo uses the index from 0 for finest level (original problem size) ~ N for the coarsest level (the coarsest solver), and its level counts is N (N multigrid level generation).

Member Function Documentation

◆ apply_uses_initial_guess()

bool gko::solver::Multigrid::apply_uses_initial_guess ( ) const

inlineoverride

Return true as iterative solvers use the data in x as an initial guess or false if multigrid always set the input as zero.

Returns: bool it is related to parameters variable zero_guess

References gko::solver::provided.

◆ get_coarsest_solver()

std::shared_ptr<const LinOp> gko::solver::Multigrid::get_coarsest_solver ( ) const

inline

Gets the operator at the coarsest level.

Returns: the coarsest operator

◆ get_cycle()

multigrid::cycle gko::solver::Multigrid::get_cycle ( ) const

inline

Get the cycle of multigrid.

Returns: the multigrid::cycle

References gko::solver::Multigrid::parameters_type::cycle.

◆ get_mg_level_list()

std::vector<std::shared_ptr<const gko::multigrid::MultigridLevel> > gko::solver::Multigrid::get_mg_level_list ( ) const

inline

Gets the list of MultigridLevel operators.

Returns: the list of MultigridLevel operators

◆ get_mid_smoother_list()

std::vector<std::shared_ptr<const LinOp> > gko::solver::Multigrid::get_mid_smoother_list ( ) const

inline

Gets the list of mid-smoother operators.

Returns: the list of mid-smoother operators

◆ get_post_smoother_list()

std::vector<std::shared_ptr<const LinOp> > gko::solver::Multigrid::get_post_smoother_list ( ) const

inline

Gets the list of post-smoother operators.

Returns: the list of post-smoother operators

◆ get_pre_smoother_list()

std::vector<std::shared_ptr<const LinOp> > gko::solver::Multigrid::get_pre_smoother_list ( ) const

inline

Gets the list of pre-smoother operators.

Returns: the list of pre-smoother operators

◆ parse()

static parameters_type gko::solver::Multigrid::parse	(	const config::pnode &	config,
		const config::registry &	context,
		const config::type_descriptor &	td_for_child = `config::make_type_descriptor<>()`
	)

static

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

config	the property tree for setting
context	the registry
td_for_child	the type descriptor for children configs

Returns: parameters

Note: Multigrid does not support the selector option in file config

◆ set_cycle()

void gko::solver::Multigrid::set_cycle ( multigrid::cycle cycle )

inline

Set the cycle of multigrid.

Parameters

multigrid::cycle the new cycle

References gko::solver::Multigrid::parameters_type::cycle.

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

ginkgo/core/solver/multigrid.hpp

Classes

Public Member Functions

Static Public Member Functions

Friends

Additional Inherited Members

Detailed Description

Member Function Documentation

◆ apply_uses_initial_guess()

◆ get_coarsest_solver()

◆ get_cycle()

◆ get_mg_level_list()

◆ get_mid_smoother_list()

◆ get_post_smoother_list()

◆ get_pre_smoother_list()

◆ parse()

◆ set_cycle()