A time step calculator that uses the smallest global physics suggested dt and the result of the previous time step to determine the next time step size. More...

#include <stability_dt.h>

Inheritance diagram for wxm::dt_calc::stability_dt:

Detailed Description

A time step calculator that uses the smallest global physics suggested dt and the result of the previous time step to determine the next time step size.

First, the success of the last time step and global minimum physics suggested dt is found (through MPI all reduce).

The next suggested time step is determined based on three cases:

Case 1: If previous attempted step was a failure AND current suggested dt is smaller then the dt of the last time step, apply a safety factor to the current minimum suggested dt.
Case 2a: If last time step was a success, stability dt will try to grow the previous time step by _growth_factor.
Case 2b: If the current suggested dt is less than the increased time step, the suggested minimum dt is used instead.

Finally, if the dt decided on is less than user provided _min_dt, the simulation exits.

Public Member Functions
	stability_dt (const WmConstOpaquePtr &parent_solver)

void	setup (const WxCryptSet &wxc) override
	Setup object using supplied crypset.

TimestepDecision	test_dt (const WxStepperStatus &stab) override
	Test whether the provided step status is acceptable, and recommend a timestep to take.

Public Member Functions inherited from wxm::dt_calc::time_stepper_base
	time_stepper_base (const WmConstOpaquePtr &parent_solver)

void	setup (const WxCryptSet &wxc) override
	Setup object using supplied crypset.

bool	needsDomain () const override
	Return true if this updater needs a domain to work on.

WxStepperStatus	step () override
	not used, just here to have the WxStepper interface

void	typeCheck () override
	not used, just here to implement WmHostAction interface

virtual bool	allow_retry () const

virtual TimestepDecision	test_dt (const WxStepperStatus &status)=0
	Test whether the provided step status is acceptable, and recommend a timestep to take.

Public Member Functions inherited from WmHostAction
	~WmHostAction () override
	Destroy hostaction.

void	setup (const WxCryptSet &wxc) override
	Setup hostaction object using supplied cryptset.

std::vector< std::string >	readVarNames () const
	Get names of all read variables used.

std::vector< std::string >	writeVarNames () const
	Get names of all write variables used.

unsigned	numExpectedReadVars () const
	Return number of read variables expected by this hostaction, or minimum number required for hostactions allowing variable number of read vars.

unsigned	numExpectedWriteVars () const
	Return number of write variables expected by this hostaction, or minimum number required for hostactions allowing variable number of write vars.

bool	allowsVariableReadVars () const
	Does this hostaction allow variable number of read variables?

bool	allowsVariableWriteVars () const
	Does this hostaction allow variable number of write variables?

virtual bool	needsDomain () const
	Return true if this updater needs a domain to work on.

void	setParentStepHandler (WmExecutionStep< WmHostAction > *parentStepHandler)
	Set enclosing step handler TODO: convert this to being a friend function or something.

unsigned	numActualReadVars () const
	Get number of actual read variables used when user calls this hostaction.

unsigned	numActualWriteVars () const
	Get number of actual write variables used when user calls this hostaction.

const WmDomain &	getDomain () const
	Get (unstructured) domain on which host action works.

std::vector< std::string >	getWriteVarList () const
	Returns list of write variables for this hostaction.

std::vector< std::string >	getReadVarList () const
	Returns list of read variables for this hostaction.

const WmSolverBase &	getParent () const
	Get parent solver object.

Public Member Functions inherited from WxStepper
	WxStepper ()
	Create a new stepper.

virtual	~WxStepper ()
	Dtor: destroy object.

void	setDt (time_t dt)
	Set time-step for the step method.

time_t	getDt () const
	Get time-step for the step method.

void	setTimeData (const WxStepper &timeData)
	Set time data for the step method.

void	setCurrentTime (time_t tcurr)
	Set current time.

time_t	incrementCurrentTime (time_t tadd)
	Increment current time.

time_t	getCurrentTime () const
	Get the current time.

void	setCurrentFrame (int frame)
	Set current frame number.

int	incrementCurrentFrame ()
	Increment current frame number.

int	getCurrentFrame () const
	Get the current frame number.

virtual WxStepperStatus	step ()=0
	Advance the stepper by assigned time step.

virtual WxStepperStatus	end ()
	Perform actions only done at simulation end.

Public Member Functions inherited from WxObject
virtual	~WxObject ()
	Dtor: destroy object.

void	setIo (WxIoBase &io)
	Set the I/O pointer for use in object.

void	setMsg (WxMsgBase &msg)
	Set the msg pointer for use in object.

WxIoBase &	getIo ()
	Return reference to I/O object.

const WxIoBase &	getIo () const
	Return constant reference to I/O object.

WxMsgBase &	getMsg ()
	Return reference to msg object.

const WxMsgBase &	getMsg () const
	Return const reference to msg object.

virtual void	setup (const WxCryptSet &wxc)
	Setup object using supplied crypset.

virtual void	init ()
	Initialize the object.

virtual void	finishBuild ()
	Finish building the object.

virtual void	load (WxIoBase &io, const WxIoNodeType &grpNode)
	Load object from file.

virtual void	dump (WxIoBase &io, WxIoNodeType &grpNode) const
	Dump object to file.

virtual std::string	name () const
	Get name of object.

void	setName (const std::string &nm)
	Set object's name.

Additional Inherited Members
Public Types inherited from WxStepper
typedef real	time_t
	Time scalar data type.

Public Attributes inherited from wxm::dt_calc::time_stepper_base
real	init_dt

Protected Member Functions inherited from WmHostAction
	WmHostAction (const WmConstOpaquePtr &parent_solver)
	Create new hostaction.

const std::type_info &	getVarType (const std::string &variableName) const
	Get a variable types from the parent solver.

const wxm::variable::variable_t &	getReadVar (unsigned pos) const
	Get a reference to a read variable.

wxm::variable::variable_t &	getWriteVar (unsigned pos) const
	Get a reference to a write variable.

virtual void	typeCheck ()=0
	Check that the provided variables meet the expected variable types for this hostaction.

Protected Member Functions inherited from WxObject
	WxObject ()
	Create object, that will be initialized subsequently.

	WxObject (const std::string &name)
	Create object with given name bypassing object setup phase Protected because there is no reason to have a WxObject directly, as it is meant to be a parent class.

Protected Attributes inherited from WmHostAction
bool	_allReadVarsSameType

bool	_allWriteVarsSameType

bool	_allowsVariableReadVars

bool	_allowsVariableWriteVars

bool	_WriteVarConditionHasBeenSet

bool	_ReadVarConditionHasBeenSet

unsigned	_numExpectedReadVars

unsigned	_numExpectedWriteVars

Constructor & Destructor Documentation

◆ stability_dt()

wxm::dt_calc::stability_dt::stability_dt ( const WmConstOpaquePtr & parent_solver )

inline

Member Function Documentation

◆ setup()

void wxm::dt_calc::stability_dt::setup ( const WxCryptSet & wxc )

overridevirtual

Setup object using supplied crypset.

This method should read in parameters needed to initialize it. May only be called once.

Parameters

wxc	Cryptset using which the object is set up.

Reimplemented from WxObject.

◆ test_dt()

TimestepDecision wxm::dt_calc::stability_dt::test_dt ( const WxStepperStatus & status )

overridevirtual

Test whether the provided step status is acceptable, and recommend a timestep to take.

It is the job of this method to reduce over all MPI ranks.

Parameters

status The combination of WxStepperStatus instances returned by all of the host actions which ran on this rank, during the current time step.

Returns: a decision on whether this timestep was successful, and the dt of the next timestep that should be taken.

Implements wxm::dt_calc::time_stepper_base.

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

src/hostactions/time_step/stability_dt.h