gko::experimental::reorder::Mc64< ValueType, IndexType > Class Template Reference

#include <ginkgo/core/reorder/mc64.hpp>

Inheritance diagram for gko::experimental::reorder::Mc64< ValueType, IndexType >:

Classes
struct	parameters_type

Public Types
using	value_type = ValueType
using	index_type = IndexType
using	result_type = Composition< value_type >
using	matrix_type = matrix::Csr< value_type, index_type >
Public Types inherited from gko::EnablePolymorphicAssignment< ConcreteType, ResultType >
using	result_type = ResultType
Public Types inherited from gko::ConvertibleTo< ResultType >
using	result_type = ResultType

Public Member Functions
const parameters_type &	get_parameters () const
std::unique_ptr< result_type >	generate (std::shared_ptr< const LinOp > system_matrix) const
Public Member Functions inherited from gko::EnableAbstractPolymorphicObject< AbstractObject, PolymorphicBase >
std::unique_ptr< AbstractObject >	create_default (std::shared_ptr< const Executor > exec) const
std::unique_ptr< AbstractObject >	create_default () const
std::unique_ptr< AbstractObject >	clone (std::shared_ptr< const Executor > exec) const
std::unique_ptr< AbstractObject >	clone () const
AbstractObject *	copy_from (const PolymorphicObject *other)
template<typename Derived >
std::enable_if_t< std::is_base_of< PolymorphicObject, std::decay_t< Derived > >::value, AbstractObject > *	copy_from (std::unique_ptr< Derived > &&other)
template<typename Derived >
std::enable_if_t< std::is_base_of< PolymorphicObject, std::decay_t< Derived > >::value, AbstractObject > *	copy_from (const std::unique_ptr< Derived > &other)
AbstractObject *	copy_from (const std::shared_ptr< const PolymorphicObject > &other)
AbstractObject *	move_from (ptr_param< PolymorphicObject > other)
AbstractObject *	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
std::unique_ptr< PolymorphicObject >	create_default () const
std::unique_ptr< PolymorphicObject >	clone (std::shared_ptr< const Executor > exec) const
std::unique_ptr< PolymorphicObject >	clone () const
PolymorphicObject *	copy_from (const PolymorphicObject *other)
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)
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)
PolymorphicObject *	copy_from (const std::shared_ptr< const PolymorphicObject > &other)
PolymorphicObject *	move_from (ptr_param< PolymorphicObject > other)
PolymorphicObject *	clear ()
std::shared_ptr< const Executor >	get_executor () const noexcept
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< ConcreteType, ResultType >
void	convert_to (result_type *result) const override
void	move_to (result_type *result) override
Public Member Functions inherited from gko::ConvertibleTo< ResultType >
void	convert_to (ptr_param< result_type > result) const
void	move_to (ptr_param< result_type > result)

Static Public Member Functions
static parameters_type	build ()

Friends
class	EnablePolymorphicObject< Mc64< ValueType, IndexType >, LinOpFactory >
class	enable_parameters_type< parameters_type, Mc64< ValueType, IndexType > >

Additional Inherited Members
Protected Member Functions inherited from gko::EnablePolymorphicObject< ConcreteObject, PolymorphicBase >
std::unique_ptr< PolymorphicObject >	create_default_impl (std::shared_ptr< const Executor > exec) const override
PolymorphicObject *	copy_from_impl (const PolymorphicObject *other) override
PolymorphicObject *	copy_from_impl (std::unique_ptr< PolymorphicObject > other) override
PolymorphicObject *	move_from_impl (PolymorphicObject *other) override
PolymorphicObject *	move_from_impl (std::unique_ptr< PolymorphicObject > other) override
PolymorphicObject *	clear_impl () override
Protected Member Functions inherited from gko::PolymorphicObject
	PolymorphicObject (std::shared_ptr< const Executor > exec)
	PolymorphicObject (const PolymorphicObject &other)
Protected Member Functions inherited from gko::log::EnableLogging< PolymorphicObject >
void	log (Params &&... params) const
Protected Attributes inherited from gko::log::EnableLogging< PolymorphicObject >
std::vector< std::shared_ptr< const Logger > >	loggers_

Detailed Description

template<typename ValueType = default_precision, typename IndexType = int32>
class gko::experimental::reorder::Mc64< ValueType, IndexType >

MC64 is an algorithm for permuting large entries to the diagonal of a sparse matrix. This approach can increase numerical stability of e.g. an LU factorization without pivoting. Under the assumption of working on a nonsingular square matrix, the algorithm computes a minimum weight perfect matching on a weighted edge bipartite graph of the matrix. It is described in detail in "On Algorithms for Permuting Large Entries to the Diagonal of a Sparse Matrix" (Duff, Koster, 2001, DOI: 10.1137/S0895479899358443). There are two strategies for choosing the weights supported:

• Maximizing the product of the absolute values on the diagonal. For this strategy, the weights are computed as \(c(i, j) = \log_2(a_i) - \log_2(|a(i, j)|)\) if \(a(i, j) \neq 0 \) and \(c(i, j) = \infty\) otherwise. Here, a_i is the maximum absolute value in row i of the matrix A. In this case, the implementation computes a row permutation P and row and column scaling coefficients L and R such that the matrix P*L*A*R has values with unity absolute value on the diagonal and smaller or equal entries everywhere else.
• Maximizing the sum of the absolute values on the diagonal. For this strategy, the weights are computed as \(c(i, j) = a_i - |a(i, j)|\) if \(a(i, j) \neq 0\) and \(c(i, j) = \infty\) otherwise. In this case, no scaling coefficients are computed.

This class creates a Combination of two ScaledPermutations representing the row and column permutation and scaling factors computed by this algorithm.

Template Parameters

ValueType	Type of the values of all matrices used in this class
IndexType	Type of the indices of all matrices used in this class

Member Function Documentation

build()

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

static parameters_type gko::experimental::reorder::Mc64< ValueType, IndexType >::build ( )

inlinestatic

Creates a new parameter_type to set up the factory.

generate()

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

std::unique_ptr< result_type > gko::experimental::reorder::Mc64< ValueType, IndexType >::generate

(

std::shared_ptr< const LinOp >

system_matrix

)

const

Note

This function overrides the default LinOpFactory::generate to return a Permutation instead of a generic LinOp, which would need to be cast to ScaledPermutation again to access its indices. It is only necessary because smart pointers aren't covariant.

get_parameters()

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

const parameters_type & gko::experimental::reorder::Mc64< ValueType, IndexType >::get_parameters ( ) const

inline

Returns the parameters used to construct the factory.

Returns

the parameters used to construct the factory.

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

• ginkgo/core/reorder/mc64.hpp