AppFrame::TimestepControl Class Reference

Control class for timestepping schemes. More...

#include <timestep_control.h>

Inheritance diagram for AppFrame::TimestepControl:

Collaboration diagram for AppFrame::TimestepControl:

Public Types
enum	Strategy { uniform, doubling, inner_residual }
	The time stepping strategies. More...

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., bool autonomous=false)
	Constructor setting default values.
void	parse_parameters (ParameterHandler &param)
double	start () const
	The left end of the time interval.
double	final () const
	The right end of the time interval.
double	tolerance () const
	The tolerance value controlling the time steps.
double	step () const
	The size of the current time step.
double	now () const
	The current time.
double	next (const double indicator)
	Compute the next time step according to tolerance() and the strategy().
bool	autonomous () const
	Returns true if the problem is autonomous (and therefore, no assembling is required in the time steps).
void	start (double)
	Set start value.
void	final (double)
	Set final time value.
void	tolerance (double)
	Set tolerance.
void	strategy (Strategy)
	Set strategy.
void	start_step (double)
	Set size of the first step.
void	max_step (double)
	Set size of the maximum step size.
void	autonomous (bool)
	Set the autonomous flag.
void	restart ()
	Set now() equal to start().
bool	print ()
	Return true if this timestep should be written to disk.
void	file_name_format (const char *)
	Set the output name template.
const char *	file_name_format ()

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

Private Attributes
double	start_val
double	final_val
double	tolerance_val
Strategy	strategy_val
double	start_step_val
double	max_step_val
double	min_step_val
double	current_step_val
	The size of the current time step.
double	step_val
bool	is_autonomous
double	now_val
double	print_step
double	next_print_val
char	format [30]

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.

Member Enumeration Documentation

enum AppFrame::TimestepControl::Strategy

The time stepping strategies.

These controlled by the value of TimestepControl::tolerance() and TimestepControl::start_step().

Enumerator:

uniform	Choose a uniform time step.
doubling	Start with the time step size given and double it in every step.
inner_residual	Modifies the time step according to the start residual of the inner iteration of the previous time step. This is meant to generate a sequence of time steps approaching infinity fast (for computing a stationary limit), while keeping an inner Newton iteration in its domain of convergence. If this residual was larger than the tolerance, divide the time step by two. If the residual was smaller than one half of tolerance, the time step is doubled.

Constructor & Destructor Documentation

AppFrame::TimestepControl::TimestepControl	(	double	start = 0.,
		double	final = 1.,
		double	tolerance = 1.e-2,
		double	start_step = 1.e-2,
		double	print_step = -1.,
		bool	autonomous = false
	)

Constructor setting default values.

Member Function Documentation

bool AppFrame::TimestepControl::autonomous ( ) const

inline

Returns true if the problem is autonomous (and therefore, no assembling is required in the time steps).

void AppFrame::TimestepControl::autonomous ( bool  b )

inline

Set the autonomous flag.

static void AppFrame::TimestepControl::declare_parameters ( ParameterHandler &  param )

static

void AppFrame::TimestepControl::file_name_format ( const char *  fmt )

inline

Set the output name template.

const char * AppFrame::TimestepControl::file_name_format ( )

inline

double AppFrame::TimestepControl::final ( ) const

inline

The right end of the time interval.

The control mechanism ensures that the final time step ends at this point.

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

inline

Set final time value.

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

inline

Set size of the maximum step size.

double AppFrame::TimestepControl::next

(

const double

indicator

)

Compute the next time step according to tolerance() and the strategy().

Takes the control object of the inner iteration for input.

double AppFrame::TimestepControl::now ( ) const

inline

The current time.

void AppFrame::TimestepControl::parse_parameters

(

ParameterHandler &

param

)

bool AppFrame::TimestepControl::print

(

)

Return true if this timestep should be written to disk.

void AppFrame::TimestepControl::restart ( )

inline

Set now() equal to start().

Initialize step() and print() to their initial values.

double AppFrame::TimestepControl::start ( ) const

inline

The left end of the time interval.

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

inline

Set start value.

void AppFrame::TimestepControl::start_step ( double  t )

inline

Set size of the first step.

This may be overwritten by the time stepping strategy.

double AppFrame::TimestepControl::step ( ) const

inline

The size of the current time step.

void AppFrame::TimestepControl::strategy ( Strategy  t )

inline

Set strategy.

double AppFrame::TimestepControl::tolerance ( ) const

inline

The tolerance value controlling the time steps.

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

inline

Set tolerance.

Member Data Documentation

double AppFrame::TimestepControl::current_step_val

private

The size of the current time step.

This may differ from step_val, if we aimed at a print_step.

double AppFrame::TimestepControl::final_val

private

char AppFrame::TimestepControl::format[30]

private

bool AppFrame::TimestepControl::is_autonomous

private

double AppFrame::TimestepControl::max_step_val

private

double AppFrame::TimestepControl::min_step_val

private

double AppFrame::TimestepControl::next_print_val

private

double AppFrame::TimestepControl::now_val

private

double AppFrame::TimestepControl::print_step

private

double AppFrame::TimestepControl::start_step_val

private

double AppFrame::TimestepControl::start_val

private

double AppFrame::TimestepControl::step_val

private

Strategy AppFrame::TimestepControl::strategy_val

private

double AppFrame::TimestepControl::tolerance_val

private

---

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

• timestep_control.h