gko::multigrid::Pgm< ValueType, IndexType > Class Template Reference

Parallel graph match (Pgm) is the aggregate method introduced in the paper M. More...

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

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

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

Classes
struct	parameters_type
class	Factory

Public Types
using	value_type = ValueType
using	index_type = IndexType
Public Types inherited from gko::EnablePolymorphicAssignment< Pgm< default_precision, int32 > >
using	result_type
Public Types inherited from gko::multigrid::EnableMultigridLevel< default_precision >
using	value_type
Public Types inherited from gko::UseComposition< default_precision >
using	value_type

Public Member Functions
std::shared_ptr< const LinOp >	get_system_matrix () const
	Returns the system operator (matrix) of the linear system.
IndexType *	get_agg () noexcept
	Returns the aggregate group.
const IndexType *	get_const_agg () const noexcept
	Returns the aggregate group.
const parameters_type &	get_parameters () const
Public Member Functions inherited from gko::EnableLinOp< Pgm< default_precision, int32 > >
const Pgm< default_precision, int32 > *	apply (ptr_param< const LinOp > b, ptr_param< LinOp > x) const
Public Member Functions inherited from gko::EnablePolymorphicAssignment< Pgm< default_precision, int32 > >
void	convert_to (result_type *result) const override
void	move_to (result_type *result) override
Public Member Functions inherited from gko::multigrid::EnableMultigridLevel< default_precision >
std::shared_ptr< const LinOp >	get_fine_op () const override
	Returns the operator on fine level.
std::shared_ptr< const LinOp >	get_restrict_op () const override
	Returns the restrict operator.
std::shared_ptr< const LinOp >	get_coarse_op () const override
	Returns the operator on coarse level.
std::shared_ptr< const LinOp >	get_prolong_op () const override
	Returns the prolong operator.
Public Member Functions inherited from gko::UseComposition< default_precision >
std::shared_ptr< Composition< default_precision > >	get_composition () const
	Returns the composition operators.
std::shared_ptr< const LinOp >	get_operator_at (size_type index) const
	Returns the operator at index-th position of composition.

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 >())
	Create the parameters from the property_tree.

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

Detailed Description

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

Parallel graph match (Pgm) is the aggregate method introduced in the paper M.

Naumov et al., "AmgX: A Library for GPU Accelerated Algebraic Multigrid and Preconditioned Iterative Methods". Current implementation only contains size = 2 version.

Pgm creates the aggregate group according to the matrix value not the structure. Pgm gives two steps (one-phase handshaking) to group the elements. 1: get the strongest neighbor of each unaggregated element. 2: group the elements whose strongest neighbor is each other. repeating until reaching the given conditions. After that, the un-aggregated elements are assigned to an aggregated group or are left alone.

Template Parameters

ValueType	precision of matrix elements
IndexType	precision of matrix indexes

Member Function Documentation

get_agg()

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

IndexType * gko::multigrid::Pgm< ValueType, IndexType >::get_agg ( )

inlinenoexcept

Returns the aggregate group.

Aggregate group whose size is same as the number of rows. Stores the mapping information from row index to coarse row index. i.e., agg[row_idx] = coarse_row_idx.

Returns

the aggregate group.

get_const_agg()

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

const IndexType * gko::multigrid::Pgm< ValueType, IndexType >::get_const_agg ( ) const

inlinenoexcept

Returns the aggregate group.

Aggregate group whose size is same as the number of rows. Stores the mapping information from row index to coarse row index. i.e., agg[row_idx] = coarse_row_idx.

Returns

the aggregate group.

Note

This is the constant version of the function, which can be significantly more memory efficient than the non-constant version, so always prefer this version.

get_system_matrix()

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

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

inline

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

Returns

the system operator (matrix)

parse()

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

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

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/index type of this class.

Returns

parameters

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

• ginkgo/core/distributed/matrix.hpp
• ginkgo/core/multigrid/pgm.hpp