Forward Euler time stepper. More...

#include <Tempus_StepperForwardEuler_decl.hpp>

Inheritance diagram for Tempus::StepperForwardEuler< Scalar >:

Public Member Functions
	StepperForwardEuler ()
	Default constructor. More...

	StepperForwardEuler (const Teuchos::RCP< const Thyra::ModelEvaluator< Scalar > > &appModel, Teuchos::RCP< Teuchos::ParameterList > pList=Teuchos::null)
	Constructor. More...

Basic stepper methods
virtual void	setObserver (Teuchos::RCP< StepperObserver< Scalar > > obs=Teuchos::null)
	Set Observer. More...

virtual void	initialize ()
	Initialize during construction and after changing input parameters. More...

virtual void	setInitialConditions (const Teuchos::RCP< SolutionHistory< Scalar > > &solutionHistory)
	Set the initial conditions, make them consistent, and set needed memory. More...

virtual void	takeStep (const Teuchos::RCP< SolutionHistory< Scalar > > &solutionHistory)
	Take the specified timestep, dt, and return true if successful. More...

virtual Teuchos::RCP < Tempus::StepperState< Scalar > >	getDefaultStepperState ()
	Get a default (initial) StepperState. More...

virtual Scalar	getOrder () const

virtual Scalar	getOrderMin () const

virtual Scalar	getOrderMax () const

virtual OrderODE	getOrderODE () const

ParameterList methods
void	setParameterList (const Teuchos::RCP< Teuchos::ParameterList > &pl)

Teuchos::RCP < Teuchos::ParameterList >	getNonconstParameterList ()

Teuchos::RCP < Teuchos::ParameterList >	unsetParameterList ()

Teuchos::RCP< const Teuchos::ParameterList >	getValidParameters () const

Teuchos::RCP < Teuchos::ParameterList >	getDefaultParameters () const

Overridden from Teuchos::Describable
virtual std::string	description () const

virtual void	describe (Teuchos::FancyOStream &out, const Teuchos::EVerbosityLevel verbLevel) const

Public Member Functions inherited from Tempus::StepperExplicit< Scalar >
virtual void	setModel (const Teuchos::RCP< const Thyra::ModelEvaluator< Scalar > > &appModel)

virtual void	setNonConstModel (const Teuchos::RCP< Thyra::ModelEvaluator< Scalar > > &appModel)

virtual Teuchos::RCP< const Thyra::ModelEvaluator< Scalar > >	getModel ()

virtual Scalar	getInitTimeStep (const Teuchos::RCP< SolutionHistory< Scalar > > &) const

virtual void	setSolver (std::string solverName)
	Set solver via ParameterList solver name. More...

virtual void	setSolver (Teuchos::RCP< Teuchos::ParameterList > solverPL=Teuchos::null)
	Set solver via solver ParameterList. More...

virtual void	setSolver (Teuchos::RCP< Thyra::NonlinearSolverBase< Scalar > > solver)
	Set solver. More...

virtual Teuchos::RCP < Thyra::NonlinearSolverBase < Scalar > >	getSolver () const
	Get solver. More...

virtual std::string	getStepperType () const

virtual void	setInitialGuess (Teuchos::RCP< const Thyra::VectorBase< Scalar > >)
	Pass initial guess to Newton solver (only relevant for implicit solvers) More...

virtual bool	isExplicit () const

virtual bool	isImplicit () const

virtual bool	isExplicitImplicit () const

virtual bool	isOneStepMethod () const

virtual bool	isMultiStepMethod () const

virtual bool	getEmbedded () const

virtual void	setUseFSAL (bool a)

virtual bool	getUseFSAL () const

virtual void	setICConsistency (std::string s)

virtual std::string	getICConsistency () const

virtual void	setICConsistencyCheck (bool c)

virtual bool	getICConsistencyCheck () const

virtual void	setStepperX (Teuchos::RCP< Thyra::VectorBase< Scalar > > x)
	Set x for Stepper storage. More...

virtual void	setStepperXDot (Teuchos::RCP< Thyra::VectorBase< Scalar > > xDot)
	Set xDot for Stepper storage. More...

virtual void	setStepperXDotDot (Teuchos::RCP< Thyra::VectorBase< Scalar > > xDotDot)
	Set x for Stepper storage. More...

virtual Teuchos::RCP < Thyra::VectorBase< Scalar > >	getStepperX (Teuchos::RCP< SolutionState< Scalar > > state)
	Get x from SolutionState or Stepper storage. More...

virtual Teuchos::RCP < Thyra::VectorBase< Scalar > >	getStepperXDot (Teuchos::RCP< SolutionState< Scalar > > state)
	Get xDot from SolutionState or Stepper storage. More...

virtual Teuchos::RCP < Thyra::VectorBase< Scalar > >	getStepperXDotDot (Teuchos::RCP< SolutionState< Scalar > > state)
	Get xDotDot from SolutionState or Stepper storage. More...

virtual void	evaluateExplicitODE (Teuchos::RCP< Thyra::VectorBase< Scalar > > xDot, Teuchos::RCP< const Thyra::VectorBase< Scalar > > x, const Scalar time)
	Evaluate xDot = f(x,t). More...

virtual void	evaluateExplicitODE (Teuchos::RCP< Thyra::VectorBase< Scalar > > xDotDot, Teuchos::RCP< const Thyra::VectorBase< Scalar > > x, Teuchos::RCP< const Thyra::VectorBase< Scalar > > xDot, const Scalar time)
	Evaluate xDotDot = f(x, xDot, t). More...

Public Member Functions inherited from Tempus::Stepper< Scalar >
virtual void	modelWarning () const

void	getValidParametersBasic (Teuchos::RCP< Teuchos::ParameterList > pl) const

virtual void	createSubSteppers (std::vector< Teuchos::RCP< const Thyra::ModelEvaluator< Scalar > > >)

void	validExplicitODE (const Teuchos::RCP< const Thyra::ModelEvaluator< Scalar > > &model) const
	Validate that the model supports explicit ODE evaluation, f(x,t) [=xdot]. More...

void	validSecondOrderExplicitODE (const Teuchos::RCP< const Thyra::ModelEvaluator< Scalar > > &model) const
	Validate that the model supports explicit second order ODE evaluation, f(x,xdot,t) [=xdotdot]. More...

void	validImplicitODE_DAE (const Teuchos::RCP< const Thyra::ModelEvaluator< Scalar > > &model) const
	Validate ME supports implicit ODE/DAE evaluation, f(xdot,x,t) [= 0]. More...

void	validSecondOrderODE_DAE (const Teuchos::RCP< const Thyra::ModelEvaluator< Scalar > > &model) const
	Validate ME supports 2nd order implicit ODE/DAE evaluation, f(xdotdot,xdot,x,t) [= 0]. More...

Teuchos::RCP < Teuchos::ParameterList >	defaultSolverParameters () const

Protected Attributes
Teuchos::RCP < StepperForwardEulerObserver < Scalar > >	stepperFEObserver_

Protected Attributes inherited from Tempus::StepperExplicit< Scalar >
Teuchos::RCP < Teuchos::ParameterList >	stepperPL_

Teuchos::RCP< const Thyra::ModelEvaluator< Scalar > >	appModel_
	Explicit ODE ModelEvaluator. More...

Thyra::ModelEvaluatorBase::InArgs < Scalar >	inArgs_

Thyra::ModelEvaluatorBase::OutArgs < Scalar >	outArgs_

Teuchos::RCP< StepperObserver < Scalar > >	stepperObserver_

Teuchos::RCP < Thyra::VectorBase< Scalar > >	stepperX_

Teuchos::RCP < Thyra::VectorBase< Scalar > >	stepperXDot_

Teuchos::RCP < Thyra::VectorBase< Scalar > >	stepperXDotDot_

Detailed Description

template<class Scalar>
class Tempus::StepperForwardEuler< Scalar >

Forward Euler time stepper.

For the explicit ODE system,

$\dot{x} = \bar{f}(x,t),$

the Forward Euler stepper can be written as

$x_{n} = x_{n-1} + \Delta t\, \bar{f}(x_{n-1},t_{n-1})$

Forward Euler is an explicit time stepper (i.e., no solver used). Note that the time derivative by definition is

$\dot{x}_{n} = \bar{f}(x_{n},t_{n}),$

Algorithm The single-timestep algorithm for Forward Euler is simply,

$\dot{x}_{n-1} \leftarrow \bar{f}(x_{n-1},t_{n-1})$
$x_{n} \leftarrow x_{n-1} + \Delta t\, \dot{x}_{n-1}$

Note that $x_n$ and $\dot{x}_{n-1}$ are not at the same time level at the end of the time step (i.e., they are not sync'ed).

To have them at the same time level, we can use the First-Step-As-Last (FSAL) principle where the function evaulation from the last time step can be used as the first function evalulation of the current step. For the Forward Euler, the FSAL algorithm is

$x_{n} \leftarrow x_{n-1} + \Delta t\, \dot{x}_{n-1}$
$\dot{x}_n \leftarrow \bar{f}(x_{n},t_{n})$

The default for Forward Euler is to use FSAL (useFSAL=true).

Definition at line 53 of file Tempus_StepperForwardEuler_decl.hpp.

Constructor & Destructor Documentation

template<class Scalar >

Tempus::StepperForwardEuler< Scalar >::StepperForwardEuler ( )

Default constructor.

Constructs with a default ParameterList.
Can reset ParameterList with setParameterList().
Requires subsequent setModel() and initialize() calls before calling takeStep().

Definition at line 19 of file Tempus_StepperForwardEuler_impl.hpp.

template<class Scalar >

Tempus::StepperForwardEuler< Scalar >::StepperForwardEuler	(	const Teuchos::RCP< const Thyra::ModelEvaluator< Scalar > > &	appModel,
		Teuchos::RCP< Teuchos::ParameterList >	pList = `Teuchos::null`
	)

Constructor.

Definition at line 26 of file Tempus_StepperForwardEuler_impl.hpp.

Member Function Documentation

template<class Scalar >

void Tempus::StepperForwardEuler< Scalar >::describe	(	Teuchos::FancyOStream &	out,
		const Teuchos::EVerbosityLevel	verbLevel
	)		const

virtual

Definition at line 183 of file Tempus_StepperForwardEuler_impl.hpp.

template<class Scalar >

std::string Tempus::StepperForwardEuler< Scalar >::description ( ) const

virtual

Definition at line 175 of file Tempus_StepperForwardEuler_impl.hpp.

template<class Scalar >

Teuchos::RCP< Teuchos::ParameterList > Tempus::StepperForwardEuler< Scalar >::getDefaultParameters ( ) const

virtual

Implements Tempus::Stepper< Scalar >.

Definition at line 231 of file Tempus_StepperForwardEuler_impl.hpp.

template<class Scalar >

Teuchos::RCP< Tempus::StepperState< Scalar > > Tempus::StepperForwardEuler< Scalar >::getDefaultStepperState ( )

virtual

Get a default (initial) StepperState.

Provide a StepperState to the SolutionState. This Stepper does not have any special state data, so just provide the base class StepperState with the Stepper description. This can be checked to ensure that the input StepperState can be used by this Stepper.

Implements Tempus::Stepper< Scalar >.

Definition at line 166 of file Tempus_StepperForwardEuler_impl.hpp.

template<class Scalar >

Teuchos::RCP< Teuchos::ParameterList > Tempus::StepperForwardEuler< Scalar >::getNonconstParameterList ( )

Definition at line 246 of file Tempus_StepperForwardEuler_impl.hpp.

template<class Scalar >

virtual Scalar Tempus::StepperForwardEuler< Scalar >::getOrder ( ) const

inlinevirtual

Implements Tempus::Stepper< Scalar >.

Definition at line 89 of file Tempus_StepperForwardEuler_decl.hpp.

template<class Scalar >

virtual Scalar Tempus::StepperForwardEuler< Scalar >::getOrderMax ( ) const

inlinevirtual

Implements Tempus::Stepper< Scalar >.

Definition at line 91 of file Tempus_StepperForwardEuler_decl.hpp.

template<class Scalar >

virtual Scalar Tempus::StepperForwardEuler< Scalar >::getOrderMin ( ) const

inlinevirtual

Implements Tempus::Stepper< Scalar >.

Definition at line 90 of file Tempus_StepperForwardEuler_decl.hpp.

template<class Scalar >

virtual OrderODE Tempus::StepperForwardEuler< Scalar >::getOrderODE ( ) const

inlinevirtual

Implements Tempus::Stepper< Scalar >.

Definition at line 93 of file Tempus_StepperForwardEuler_decl.hpp.

template<class Scalar >

Teuchos::RCP< const Teuchos::ParameterList > Tempus::StepperForwardEuler< Scalar >::getValidParameters ( ) const

Definition at line 216 of file Tempus_StepperForwardEuler_impl.hpp.

template<class Scalar >

void Tempus::StepperForwardEuler< Scalar >::initialize ( )

virtual

Initialize during construction and after changing input parameters.

Implements Tempus::Stepper< Scalar >.

Definition at line 62 of file Tempus_StepperForwardEuler_impl.hpp.

template<class Scalar >

void Tempus::StepperForwardEuler< Scalar >::setInitialConditions ( const Teuchos::RCP< SolutionHistory< Scalar > > & solutionHistory )

virtual

Set the initial conditions, make them consistent, and set needed memory.

Reimplemented from Tempus::StepperExplicit< Scalar >.

Definition at line 74 of file Tempus_StepperForwardEuler_impl.hpp.

template<class Scalar >

void Tempus::StepperForwardEuler< Scalar >::setObserver ( Teuchos::RCP< StepperObserver< Scalar > > obs = Teuchos::null )

virtual

Set Observer.

Implements Tempus::Stepper< Scalar >.

Definition at line 42 of file Tempus_StepperForwardEuler_impl.hpp.

template<class Scalar >

void Tempus::StepperForwardEuler< Scalar >::setParameterList ( const Teuchos::RCP< Teuchos::ParameterList > & pl )

Definition at line 193 of file Tempus_StepperForwardEuler_impl.hpp.

template<class Scalar >

void Tempus::StepperForwardEuler< Scalar >::takeStep ( const Teuchos::RCP< SolutionHistory< Scalar > > & solutionHistory )

virtual

Take the specified timestep, dt, and return true if successful.

Implements Tempus::Stepper< Scalar >.

Definition at line 89 of file Tempus_StepperForwardEuler_impl.hpp.

template<class Scalar >

Teuchos::RCP< Teuchos::ParameterList > Tempus::StepperForwardEuler< Scalar >::unsetParameterList ( )

Definition at line 254 of file Tempus_StepperForwardEuler_impl.hpp.

Member Data Documentation

template<class Scalar >

Teuchos::RCP<StepperForwardEulerObserver<Scalar> > Tempus::StepperForwardEuler< Scalar >::stepperFEObserver_

protected

Definition at line 114 of file Tempus_StepperForwardEuler_decl.hpp.

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

http://docs.trilinos.org/r12.16/packages/tempus/src/Tempus_StepperForwardEuler_decl.hpp
http://docs.trilinos.org/r12.16/packages/tempus/src/Tempus_StepperForwardEuler_impl.hpp

Public Member Functions

Protected Attributes

Detailed Description

template<class Scalar> class Tempus::StepperForwardEuler< Scalar >

Constructor & Destructor Documentation

Member Function Documentation

Member Data Documentation

template<class Scalar>
class Tempus::StepperForwardEuler< Scalar >