#include <deal.II/algorithms/newton.h>

Inheritance diagram for Algorithms::Newton< VectorType >:

[legend]

Public Member Functions
	Newton (OperatorBase &residual, OperatorBase &inverse_derivative)

void	parse_parameters (ParameterHandler &param)

void	initialize (OutputOperator< VectorType > &output)

virtual void	operator() (AnyData &out, const AnyData &in) override

virtual void	notify (const Event &) override

double	threshold (double new_value)

void	clear_events ()

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

EnableObserverPointer functionality
Classes derived from EnableObserverPointer provide a facility to subscribe to this object. This is mostly used by the ObserverPointer class.
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

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

static ::ExceptionBase &	ExcInUse (int arg1, std::string arg2, std::string arg3)

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

Public Attributes
ReductionControl	control

bool	debug_vectors

unsigned int	debug

Protected Attributes
Event	notifications

Private Types
using	map_value_type = decltype(counter_map)::value_type

using	map_iterator = decltype(counter_map)::iterator

Private Member Functions
void	check_no_subscribers () const noexcept

Private Attributes
ObserverPointer< OperatorBase, Newton< VectorType > >	residual

ObserverPointer< OperatorBase, Newton< VectorType > >	inverse_derivative

ObserverPointer< OutputOperator< VectorType >, Newton< VectorType > >	data_out

bool	assemble_now

unsigned int	n_stepsize_iterations

double	assemble_threshold

std::atomic< unsigned int >	counter

std::map< std::string, unsigned int >	counter_map

std::vector< std::atomic< bool > * >	validity_pointers

const std::type_info *	object_info

Static Private Attributes
static std::mutex	mutex

Detailed Description

template<typename VectorType>
class Algorithms::Newton< VectorType >

Operator class performing Newton's iteration with standard step size control and adaptive matrix generation.

This class performs a Newton iteration up to convergence determined by control. If after an update the norm of the residual has become larger, then step size control is activated and the update is subsequently divided by two until the residual actually becomes smaller (or the minimal scaling factor determined by n_stepsize_iterations is reached).

Since assembling matrices, depending on the implementation, tends to be costly, this method applies an adaptive reassembling strategy. Only if the reduction factor for the residual is more than threshold, the event Algorithms::bad_derivative is submitted to inverse_derivative. It is up to this object to implement reassembling accordingly.

Contents of the AnyData objects

The only value used by the Newton method is the first vector in the parameter out of operator()(). It serves as the start vector of Newton's method and in the end contains the solution. All other vectors of out are ignored by Newton's method and its inner Operator objects. All vectors of in are forwarded to the inner Operator objects, with additional information added as follows.

When calling (*residual)(), the AnyData in given to the Newton iteration is prepended by a vector "Newton iterate", the current value of the Newton iterate, which can be used to evaluate the residual at this point.

For the call to (*inverse_derivative), the vector "Newton residual" is inserted before "Newton iterate".

Definition at line 71 of file newton.h.

Member Typedef Documentation

◆ map_value_type

using EnableObserverPointer::map_value_type = decltype(counter_map)::value_type

privateinherited

The data type used in counter_map.

Definition at line 238 of file enable_observer_pointer.h.

◆ map_iterator

using EnableObserverPointer::map_iterator = decltype(counter_map)::iterator

privateinherited

The iterator type used in counter_map.

Definition at line 243 of file enable_observer_pointer.h.

Constructor & Destructor Documentation

◆ Newton()

template<typename VectorType >

Algorithms::Newton< VectorType >::Newton	(	OperatorBase &	residual,
		OperatorBase &	inverse_derivative
	)

Constructor, receiving the applications computing the residual and solving the linear problem, respectively.

Member Function Documentation

◆ declare_parameters()

template<typename VectorType >

static void Algorithms::Newton< VectorType >::declare_parameters ( ParameterHandler & param )

static

Declare the parameters applicable to Newton's method.

◆ parse_parameters()

template<typename VectorType >

void Algorithms::Newton< VectorType >::parse_parameters ( ParameterHandler & param )

Read the parameters in the ParameterHandler.

◆ initialize()

template<typename VectorType >

void Algorithms::Newton< VectorType >::initialize ( OutputOperator< VectorType > & output )

Initialize the pointer data_out for debugging.

◆ operator()()

template<typename VectorType >

virtual void Algorithms::Newton< VectorType >::operator()	(	AnyData &	out,
		const AnyData &	in
	)

overridevirtual

The actual Newton iteration. The initial value is in out(0), which also contains the result after convergence. Values in in are not used by Newton, but will be handed down to the objects residual and inverse_derivative.

Implements Algorithms::OperatorBase.

◆ notify()

template<typename VectorType >

virtual void Algorithms::Newton< VectorType >::notify ( const Event & e )

overridevirtual

Register an event triggered by an outer iteration.

Reimplemented from Algorithms::OperatorBase.

◆ threshold()

template<typename VectorType >

double Algorithms::Newton< VectorType >::threshold ( double new_value )

Set the maximal residual reduction allowed without triggering assembling in the next step. Return the previous value.

◆ clear_events()

void Algorithms::OperatorBase::clear_events ( )

inherited

Clear all notifications.

Definition at line 46 of file operator.cc.

◆ subscribe()

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

inherited

Subscribes a user of the object by storing the pointer validity. The subscriber may be identified by text supplied as identifier.

Definition at line 131 of file enable_observer_pointer.cc.

◆ unsubscribe()

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

inherited

Unsubscribes a user from the object.

Note: The identifier and the validity pointer must be the same as the one supplied to subscribe().

Definition at line 151 of file enable_observer_pointer.cc.

◆ n_subscriptions()

unsigned int EnableObserverPointer::n_subscriptions ( ) const

inlineinherited

Return the present number of subscriptions to this object. This allows to use this class for reference counted lifetime determination where the last one to unsubscribe also deletes the object.

Definition at line 322 of file enable_observer_pointer.h.

◆ list_subscribers() [1/2]

template<typename StreamType >

void EnableObserverPointer::list_subscribers ( StreamType & stream ) const

inlineinherited

List the subscribers to the input stream.

Definition at line 339 of file enable_observer_pointer.h.

◆ list_subscribers() [2/2]

void EnableObserverPointer::list_subscribers ( ) const

inherited

List the subscribers to deallog.

Definition at line 199 of file enable_observer_pointer.cc.

◆ serialize()

template<class Archive >

void EnableObserverPointer::serialize	(	Archive &	ar,
		const unsigned int	version
	)

inlineinherited

Read or write the data of this object to or from a stream for the purpose of serialization using the BOOST serialization library.

This function does not actually serialize any of the member variables of this class. The reason is that what this class stores is only who subscribes to this object, but who does so at the time of storing the contents of this object does not necessarily have anything to do with who subscribes to the object when it is restored. Consequently, we do not want to overwrite the subscribers at the time of restoring, and then there is no reason to write the subscribers out in the first place.

Definition at line 331 of file enable_observer_pointer.h.

◆ check_no_subscribers()

void EnableObserverPointer::check_no_subscribers ( ) const

privatenoexceptinherited

Check that there are no objects subscribing to this object. If this check passes then it is safe to destroy the current object. It this check fails then this function will either abort or print an error message to deallog (by using the AssertNothrow mechanism), but will not throw an exception.

Note: Since this function is just a consistency check it does nothing in release mode.; If this function is called when there is an uncaught exception then, rather than aborting, this function prints an error message to the standard error stream and returns.

Definition at line 53 of file enable_observer_pointer.cc.

Member Data Documentation

◆ control

template<typename VectorType >

ReductionControl Algorithms::Newton< VectorType >::control

Control object for the Newton iteration.

Definition at line 120 of file newton.h.

◆ residual

template<typename VectorType >

ObserverPointer<OperatorBase, Newton<VectorType> > Algorithms::Newton< VectorType >::residual

private

The operator computing the residual.

Definition at line 126 of file newton.h.

◆ inverse_derivative

template<typename VectorType >

ObserverPointer<OperatorBase, Newton<VectorType> > Algorithms::Newton< VectorType >::inverse_derivative

private

The operator applying the inverse derivative to the residual.

Definition at line 131 of file newton.h.

◆ data_out

template<typename VectorType >

ObserverPointer<OutputOperator<VectorType>, Newton<VectorType> > Algorithms::Newton< VectorType >::data_out

private

The operator handling the output in case the debug_vectors is true. Call the initialize function first.

Definition at line 137 of file newton.h.

◆ assemble_now

template<typename VectorType >

bool Algorithms::Newton< VectorType >::assemble_now

private

This flag is set by the function assemble(), indicating that the matrix must be assembled anew upon start.

Definition at line 143 of file newton.h.

◆ n_stepsize_iterations

template<typename VectorType >

unsigned int Algorithms::Newton< VectorType >::n_stepsize_iterations

private

A flag used to decide how many stepsize iteration should be made. Default is the original value of 21.

Enter zero here to turn off stepsize control.

Note: Controlled by Stepsize iterations in parameter file

Definition at line 153 of file newton.h.

◆ assemble_threshold

template<typename VectorType >

double Algorithms::Newton< VectorType >::assemble_threshold

private

Threshold for re-assembling matrix.

If the quotient of two consecutive residuals is smaller than this threshold, the system matrix is not assembled in this step.

Note: This parameter should be adjusted to the residual gain of the inner solver.

The default values is zero, resulting in reassembling in every Newton step.

Definition at line 167 of file newton.h.

◆ debug_vectors

template<typename VectorType >

bool Algorithms::Newton< VectorType >::debug_vectors

Print residual, update and updated solution after each step into file Newton_NNN?

Definition at line 174 of file newton.h.

◆ debug

template<typename VectorType >

unsigned int Algorithms::Newton< VectorType >::debug

Write debug output to deallog; the higher the number, the more output.

Definition at line 179 of file newton.h.

◆ notifications

Event Algorithms::OperatorBase::notifications

protectedinherited

Accumulate events here. If any of those is set, the function solve() of a terminal application must take care of reassembling the matrix.

Definition at line 96 of file operator.h.

◆ counter

std::atomic<unsigned int> EnableObserverPointer::counter

mutableprivateinherited

Store the number of objects which subscribed to this object. Initially, this number is zero, and upon destruction it shall be zero again (i.e. all objects which subscribed should have unsubscribed again).

The creator (and owner) of an object is counted in the map below if HE manages to supply identification.

We use the mutable keyword in order to allow subscription to constant objects also.

This counter may be read from and written to concurrently in multithreaded code: hence we use the std::atomic class template.

Definition at line 227 of file enable_observer_pointer.h.

◆ counter_map

std::map<std::string, unsigned int> EnableObserverPointer::counter_map

mutableprivateinherited

In this map, we count subscriptions for each different identification string supplied to subscribe().

Definition at line 233 of file enable_observer_pointer.h.

◆ validity_pointers

std::vector<std::atomic<bool> *> EnableObserverPointer::validity_pointers

mutableprivateinherited

In this vector, we store pointers to the validity bool in the ObserverPointer objects that subscribe to this class.

Definition at line 249 of file enable_observer_pointer.h.

◆ object_info

const std::type_info* EnableObserverPointer::object_info

mutableprivateinherited

Pointer to the typeinfo object of this object, from which we can later deduce the class name. Since this information on the derived class is neither available in the destructor, nor in the constructor, we obtain it in between and store it here.

Definition at line 257 of file enable_observer_pointer.h.

◆ mutex

std::mutex EnableObserverPointer::mutex

staticprivateinherited

A mutex used to ensure data consistency when accessing the mutable members of this class. This lock is used in the subscribe() and unsubscribe() functions, as well as in list_subscribers().

Definition at line 280 of file enable_observer_pointer.h.

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

include/deal.II/algorithms/newton.h

Public Member Functions

Static Public Member Functions

Public Attributes

Protected Attributes

Private Types

Private Member Functions

Private Attributes

Static Private Attributes

Detailed Description

Contents of the AnyData objects

Member Typedef Documentation

◆ map_value_type

◆ map_iterator

Constructor & Destructor Documentation

◆ Newton()

Member Function Documentation

◆ declare_parameters()

◆ parse_parameters()

◆ initialize()

◆ operator()()

◆ notify()

◆ threshold()

◆ clear_events()

◆ subscribe()

◆ unsubscribe()

◆ n_subscriptions()

◆ list_subscribers() [1/2]

◆ list_subscribers() [2/2]

◆ serialize()

◆ check_no_subscribers()

Member Data Documentation

◆ control

◆ residual

◆ inverse_derivative

◆ data_out

◆ assemble_now

◆ n_stepsize_iterations

◆ assemble_threshold

◆ debug_vectors

◆ debug

◆ notifications

◆ counter

◆ counter_map

◆ validity_pointers

◆ object_info

◆ mutex