gko::solver::Cg< ValueType > Class Template Reference

CG or the conjugate gradient method is an iterative type Krylov subspace method which is suitable for symmetric positive definite methods. More...

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

Inheritance diagram for gko::solver::Cg< ValueType >:

Collaboration diagram for gko::solver::Cg< ValueType >:

Classes
struct	parameters_type
class	Factory

Public Types
using	value_type = ValueType
using	transposed_type = Cg<ValueType>
Public Types inherited from gko::EnablePolymorphicAssignment< Cg< default_precision > >
using	result_type

Public Member Functions
std::unique_ptr< LinOp >	transpose () const override
	Returns a LinOp representing the transpose of the Transposable object.
std::unique_ptr< LinOp >	conj_transpose () const override
	Returns a LinOp representing the conjugate transpose of the Transposable object.
bool	apply_uses_initial_guess () const override
	Return true as iterative solvers use the data in x as an initial guess.
const parameters_type &	get_parameters () const
Public Member Functions inherited from gko::EnableLinOp< Cg< default_precision > >
const Cg< default_precision > *	apply (ptr_param< const LinOp > b, ptr_param< LinOp > x) const
Public Member Functions inherited from gko::EnablePolymorphicAssignment< Cg< default_precision > >
void	convert_to (result_type *result) const override
void	move_to (result_type *result) override
Public Member Functions inherited from gko::solver::EnableSolverBase< Cg< default_precision > >
EnableSolverBase &	operator= (const EnableSolverBase &other)
	Creates a shallow copy of the provided system matrix, clones it onto this executor if executors don't match.
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.
Public Member Functions inherited from gko::solver::EnableIterativeBase< Cg< default_precision > >
EnableIterativeBase &	operator= (const EnableIterativeBase &other)
	Creates a shallow copy of the provided stopping criterion, clones it onto this executor if executors don't match.
void	set_stop_criterion_factory (std::shared_ptr< const stop::CriterionFactory > new_stop_factory) override
	Sets the stopping criterion of the solver.
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.
Public Member Functions inherited from gko::solver::EnablePreconditionable< Cg< default_precision > >
void	set_preconditioner (std::shared_ptr< const LinOp > new_precond) override
	Sets the preconditioner operator used by the Preconditionable.
EnablePreconditionable &	operator= (const EnablePreconditionable &other)
	Creates a shallow copy of the provided preconditioner, clones it onto this executor if executors don't match.
Public Member Functions inherited from gko::Preconditionable
virtual std::shared_ptr< const LinOp >	get_preconditioner () const
	Returns the preconditioner operator used by the Preconditionable.

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 >())
	Create the parameters from the property_tree.

Friends
class	EnableLinOp< Cg >
class	EnablePolymorphicObject< Cg, LinOp >

Detailed Description

template<typename ValueType = default_precision>
class gko::solver::Cg< ValueType >

CG or the conjugate gradient method is an iterative type Krylov subspace method which is suitable for symmetric positive definite methods.

Though this method performs very well for symmetric positive definite matrices, it is in general not suitable for general matrices.

The implementation in Ginkgo makes use of the merged kernel to make the best use of data locality. The inner operations in one iteration of CG are merged into 2 separate steps.

Template Parameters

ValueType

precision of matrix elements

Member Function Documentation

apply_uses_initial_guess()

template<typename ValueType = default_precision>

bool gko::solver::Cg< ValueType >::apply_uses_initial_guess ( ) const

inlineoverride

Return true as iterative solvers use the data in x as an initial guess.

Returns

true as iterative solvers use the data in x as an initial guess.

conj_transpose()

template<typename ValueType = default_precision>

std::unique_ptr< LinOp > gko::solver::Cg< ValueType >::conj_transpose ( ) const

overridevirtual

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

Returns

a pointer to the new conjugate transposed object

Implements gko::Transposable.

parse()

template<typename ValueType = default_precision>

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

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. The default uses the value type of this class.

Returns

parameters

transpose()

template<typename ValueType = default_precision>

std::unique_ptr< LinOp > gko::solver::Cg< ValueType >::transpose ( ) const

overridevirtual

Returns a LinOp representing the transpose of the Transposable object.

Returns

a pointer to the new transposed object

Implements gko::Transposable.

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

• ginkgo/core/solver/cg.hpp