#include <deal.II/lac/solver_control.h>

Inheritance diagram for ReductionControl:

Public Member Functions
	ReductionControl (const unsigned int maxiter=100, const double tolerance=1.e-10, const double reduce=1.e-2, const bool log_history=false, const bool log_result=true)

	ReductionControl (const SolverControl &c)

ReductionControl &	operator= (const SolverControl &c)

virtual	~ReductionControl () override=default

void	parse_parameters (ParameterHandler &param)

virtual State	check (const unsigned int step, const double check_value) override

double	reduction () const

double	set_reduction (const double)

Public Member Functions inherited from SolverControl
	SolverControl (const unsigned int n=100, const double tol=1.e-10, const bool log_history=false, const bool log_result=true)

virtual	~SolverControl () override=default

void	parse_parameters (ParameterHandler &param)

State	last_check () const

double	initial_value () const

double	last_value () const

unsigned int	last_step () const

unsigned int	max_steps () const

unsigned int	set_max_steps (const unsigned int)

void	set_failure_criterion (const double rel_failure_residual)

void	clear_failure_criterion ()

double	tolerance () const

double	set_tolerance (const double)

void	enable_history_data ()

const std::vector< double > &	get_history_data () const

double	average_reduction () const

double	final_reduction () const

double	step_reduction (unsigned int step) const

void	log_history (const bool)

bool	log_history () const

unsigned int	log_frequency (unsigned int)

void	log_result (const bool)

bool	log_result () const

Public Member Functions inherited from Subscriptor
	Subscriptor ()

	Subscriptor (const Subscriptor &)

	Subscriptor (Subscriptor &&) noexcept

virtual	~Subscriptor ()

Subscriptor &	operator= (const Subscriptor &)

Subscriptor &	operator= (Subscriptor &&) noexcept

void	subscribe (std::atomic< bool > *const validity, const std::string &identifier="") const

void	unsubscribe (std::atomic< bool > *const validity, const std::string &identifier="") const

unsigned int	n_subscriptions () const

template<typename StreamType >
void	list_subscribers (StreamType &stream) const

void	list_subscribers () const

template<class Archive >
void	serialize (Archive &ar, const unsigned int version)

Static Public Member Functions
static void	declare_parameters (ParameterHandler &param)

Static Public Member Functions inherited from SolverControl
static void	declare_parameters (ParameterHandler &param)

static ::ExceptionBase &	ExcHistoryDataRequired ()

Static Public Member Functions inherited from Subscriptor
static ::ExceptionBase &	ExcInUse (int arg1, std::string arg2, std::string arg3)

static ::ExceptionBase &	ExcNoSubscriber (std::string arg1, std::string arg2)

Protected Attributes
double	reduce

double	reduced_tol

Protected Attributes inherited from SolverControl
unsigned int	maxsteps

double	tol

State	lcheck

double	initial_val

double	lvalue

unsigned int	lstep

bool	check_failure

double	relative_failure_residual

double	failure_residual

bool	m_log_history

unsigned int	m_log_frequency

bool	m_log_result

bool	history_data_enabled

std::vector< double >	history_data

Additional Inherited Members
Public Types inherited from SolverControl
enum	State { iterate = 0, success, failure }

Detailed Description

Specialization of SolverControl which returns success if either the specified tolerance is achieved or if the initial residual (or whatever criterion was chosen by the solver class) is reduced by a given factor. This is useful in cases where you don't want to solve exactly, but rather want to gain two digits or if the maximal number of iterations is achieved. For example: The maximal number of iterations is 20, the reduction factor is 1% and the tolerance is 0.1%. The initial residual is 2.5. The process will break if 20 iteration are completed or the new residual is less then 2.5*1% or if it is less then 0.1%.

Author: Guido Kanschat

Definition at line 427 of file solver_control.h.

Constructor & Destructor Documentation

◆ ReductionControl() [1/2]

ReductionControl::ReductionControl	(	const unsigned int	maxiter = `100`,
		const double	tolerance = `1.e-10`,
		const double	reduce = `1.e-2`,
		const bool	log_history = `false`,
		const bool	log_result = `true`
	)

Constructor. Provide the reduction factor in addition to arguments that have the same meaning as those of the constructor of the SolverControl constructor.

Definition at line 227 of file solver_control.cc.

◆ ReductionControl() [2/2]

ReductionControl::ReductionControl ( const SolverControl & c )

Initialize with a SolverControl object. The result will emulate SolverControl by setting reduce to zero.

Definition at line 238 of file solver_control.cc.

◆ ~ReductionControl()

virtual ReductionControl::~ReductionControl ( )

overridevirtualdefault

Virtual destructor is needed as there are virtual functions in this class.

Member Function Documentation

◆ operator=()

ReductionControl & ReductionControl::operator= ( const SolverControl & c )

Assign a SolverControl object to ReductionControl. The result of the assignment will emulate SolverControl by setting reduce to zero.

Definition at line 248 of file solver_control.cc.

◆ declare_parameters()

void ReductionControl::declare_parameters ( ParameterHandler & param )

static

Interface to parameter file.

Definition at line 294 of file solver_control.cc.

◆ parse_parameters()

void ReductionControl::parse_parameters ( ParameterHandler & param )

Read parameters from file.

Definition at line 302 of file solver_control.cc.

◆ check()

SolverControl::State ReductionControl::check	(	const unsigned int	step,
		const double	check_value
	)

overridevirtual

Decide about success or failure of an iteration. This function calls the one in the base class, but sets the tolerance to reduction * initial value upon the first iteration.

Reimplemented from SolverControl.

Definition at line 258 of file solver_control.cc.

◆ reduction()

double ReductionControl::reduction ( ) const

Reduction factor.

◆ set_reduction()

double ReductionControl::set_reduction ( const double )

Change reduction factor.

Member Data Documentation

◆ reduce

double ReductionControl::reduce

protected

Desired reduction factor.

Definition at line 496 of file solver_control.h.

◆ reduced_tol

double ReductionControl::reduced_tol

protected

Reduced tolerance. Stop iterations if either this value is achieved or if the base class indicates success.

Definition at line 502 of file solver_control.h.

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

include/deal.II/lac/solver_control.h
source/lac/solver_control.cc

Public Member Functions

Static Public Member Functions

Protected Attributes

Additional Inherited Members