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

Inheritance diagram for Algorithms::TimestepControl:

Public Member Functions
	TimestepControl (double start=0., double final=1., double tolerance=1.e-2, double start_step=1.e-2, double print_step=-1., double max_step=1.)

void	parse_parameters (ParameterHandler &param)

double	start () const

double	final () const

double	tolerance () const

double	step () const

double	now () const

bool	advance ()

void	start (double)

void	final (double)

void	tolerance (double)

void	start_step (const double step)

void	max_step (double)

void	restart ()

bool	print ()

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

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

Private Attributes
double	start_val

double	final_val

double	tolerance_val

double	start_step_val

double	max_step_val

double	min_step_val

double	current_step_val

double	step_val

double	now_val

double	print_step

double	next_print_val

Detailed Description

Control class for timestepping schemes. Its main task is determining the size of the next time step and the according point in the time interval. Additionally, it controls writing the solution to a file.

The size of the next time step is determined as follows:

According to the strategy, the step size is tentatively added to the current time.
If the resulting time exceeds the final time of the interval, the step size is reduced in order to meet this time.
If the resulting time is below the final time by just a fraction of the step size, the step size is increased in order to meet this time.
The resulting step size is used from the current time.

The variable print_step can be used to control the amount of output generated by the timestepping scheme.

Note: Many of the features of this class are available in DiscreteTime with a more modern interface and better programming guarantees. Consider using DiscreteTime instead of TimestepControl.

Definition at line 61 of file timestep_control.h.

Constructor & Destructor Documentation

◆ TimestepControl()

TimestepControl::TimestepControl	(	double	start = `0.`,
		double	final = `1.`,
		double	tolerance = `1.e-2`,
		double	start_step = `1.e-2`,
		double	print_step = `-1.`,
		double	max_step = `1.`
	)

Constructor setting default values

Definition at line 25 of file timestep_control.cc.

Member Function Documentation

◆ declare_parameters()

void TimestepControl::declare_parameters ( ParameterHandler & param )

static

Declare the control parameters for parameter handler.

Definition at line 51 of file timestep_control.cc.

◆ parse_parameters()

void TimestepControl::parse_parameters ( ParameterHandler & param )

Read the control parameters from a parameter handler.

This function also calls restart() to reset all other internal parameters of this class to their appropriate values based on the parameters just read.

Definition at line 64 of file timestep_control.cc.

◆ start() [1/2]

double Algorithms::TimestepControl::start ( ) const

inline

Return the left end of the time interval.

Definition at line 232 of file timestep_control.h.

◆ final() [1/2]

double Algorithms::TimestepControl::final ( ) const

inline

Return the right end of the time interval. The control mechanism ensures that the final time step ends at this point.

Definition at line 239 of file timestep_control.h.

◆ tolerance() [1/2]

double Algorithms::TimestepControl::tolerance ( ) const

inline

Return the tolerance value controlling the time steps.

Definition at line 253 of file timestep_control.h.

◆ step()

double Algorithms::TimestepControl::step ( ) const

inline

Return the size of the current time step.

Definition at line 246 of file timestep_control.h.

◆ now()

double Algorithms::TimestepControl::now ( ) const

inline

Return the current time.

Definition at line 260 of file timestep_control.h.

◆ advance()

bool TimestepControl::advance ( )

Compute the size of the next step and return true if it differs from the current step size. Advance the current time by the new step size.

Definition at line 77 of file timestep_control.cc.

◆ start() [2/2]

void Algorithms::TimestepControl::start ( double t )

inline

Set start value.

Definition at line 267 of file timestep_control.h.

◆ final() [2/2]

void Algorithms::TimestepControl::final ( double t )

inline

Set final time value.

Definition at line 274 of file timestep_control.h.

◆ tolerance() [2/2]

void Algorithms::TimestepControl::tolerance ( double t )

inline

Set tolerance

Definition at line 281 of file timestep_control.h.

◆ start_step()

void Algorithms::TimestepControl::start_step ( const double step )

inline

Set size of the first step. This may be overwritten by the time stepping strategy.

Parameters

[in] step The size of the first step, which may be overwritten by the time stepping strategy.

Definition at line 288 of file timestep_control.h.

◆ max_step()

void Algorithms::TimestepControl::max_step ( double t )

inline

Set size of the maximum step size.

Definition at line 295 of file timestep_control.h.

◆ restart()

void Algorithms::TimestepControl::restart ( )

inline

Set now() equal to start(). Initialize step() and print() to their initial values.

Definition at line 302 of file timestep_control.h.

◆ print()

bool TimestepControl::print ( )

Return true if this timestep should be written to disk.

Definition at line 102 of file timestep_control.cc.

Member Data Documentation

◆ start_val

double Algorithms::TimestepControl::start_val

private

The beginning of the time interval.

Definition at line 174 of file timestep_control.h.

◆ final_val

double Algorithms::TimestepControl::final_val

private

The end of the time interval.

Definition at line 179 of file timestep_control.h.

◆ tolerance_val

double Algorithms::TimestepControl::tolerance_val

private

The tolerance value controlling the time steps.

Definition at line 184 of file timestep_control.h.

◆ start_step_val

double Algorithms::TimestepControl::start_step_val

private

The size of the first step.

Definition at line 189 of file timestep_control.h.

◆ max_step_val

double Algorithms::TimestepControl::max_step_val

private

The maximum step size.

Definition at line 194 of file timestep_control.h.

◆ min_step_val

double Algorithms::TimestepControl::min_step_val

private

The minimum step size.

Definition at line 199 of file timestep_control.h.

◆ current_step_val

double Algorithms::TimestepControl::current_step_val

private

The size of the current time step. This may differ from step_val, if we aim at final_val.

Definition at line 205 of file timestep_control.h.

◆ step_val

double Algorithms::TimestepControl::step_val

private

The size of the current time step determined by the strategy. This may differ from current_step_val, if we aim at final_val.

Definition at line 211 of file timestep_control.h.

◆ now_val

double Algorithms::TimestepControl::now_val

private

The current time.

Definition at line 216 of file timestep_control.h.

◆ print_step

double Algorithms::TimestepControl::print_step

private

Determines the approximate time interval between generated outputs. If negative, output will be generated at all time steps.

Definition at line 222 of file timestep_control.h.

◆ next_print_val

double Algorithms::TimestepControl::next_print_val

private

If current time exceeds this value, it is time to generate the output.

Definition at line 227 of file timestep_control.h.

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

include/deal.II/algorithms/timestep_control.h
source/algorithms/timestep_control.cc

Public Member Functions

Static Public Member Functions

Private Attributes

Detailed Description

Constructor & Destructor Documentation

◆ TimestepControl()

Member Function Documentation

◆ declare_parameters()

◆ parse_parameters()

◆ start() [1/2]

◆ final() [1/2]

◆ tolerance() [1/2]

◆ step()

◆ now()

◆ advance()

◆ start() [2/2]

◆ final() [2/2]

◆ tolerance() [2/2]

◆ start_step()

◆ max_step()

◆ restart()

◆ print()

Member Data Documentation

◆ start_val

◆ final_val

◆ tolerance_val

◆ start_step_val

◆ max_step_val

◆ min_step_val

◆ current_step_val

◆ step_val

◆ now_val

◆ print_step

◆ next_print_val