Leapfrog time stepper. More...

#include <Tempus_StepperLeapfrog_decl.hpp>

Inheritance diagram for Tempus::StepperLeapfrog< Scalar >:

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

	StepperLeapfrog (const Teuchos::RCP< const Thyra::ModelEvaluator< Scalar > > &appModel, const Teuchos::RCP< StepperObserver< Scalar > > &obs, bool useFSAL, std::string ICConsistency, bool ICConsistencyCheck)
	Constructor. More...

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

std::string	getICConsistencyDefault () const

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

virtual Teuchos::RCP < StepperObserver< Scalar > >	getObserver () const
	Get 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 and make them consistent. 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 Scalar	getInitTimeStep (const Teuchos::RCP< SolutionHistory< Scalar > > &) const

virtual bool	isExplicit () const

virtual bool	isImplicit () const

virtual bool	isExplicitImplicit () const

virtual bool	isOneStepMethod () const

virtual bool	isMultiStepMethod () const

virtual OrderODE	getOrderODE () const

Overridden from Teuchos::Describable
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 void	setSolver (Teuchos::RCP< Thyra::NonlinearSolverBase< Scalar > > solver=Teuchos::null)
	Set solver. More...

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

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

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, const Teuchos::RCP< ExplicitODEParameters< Scalar > > &p)
	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, const Teuchos::RCP< ExplicitODEParameters< Scalar > > &p)
	Evaluate xDotDot = f(x, xDot, t). More...

Public Member Functions inherited from Tempus::Stepper< Scalar >
void	setStepperType (std::string s)

std::string	getStepperType () const

void	setUseFSAL (bool a)

bool	getUseFSAL () const

virtual bool	getUseFSALDefault () const

void	setICConsistency (std::string s)

std::string	getICConsistency () const

void	setICConsistencyCheck (bool c)

bool	getICConsistencyCheck () const

virtual bool	getICConsistencyCheckDefault () const

virtual std::string	description () const

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

Protected Attributes
Teuchos::RCP < StepperObserverComposite < Scalar > >	stepperObserver_

Teuchos::RCP < StepperLeapfrogObserver < Scalar > >	stepperLFObserver_

Protected Attributes inherited from Tempus::StepperExplicit< Scalar >
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::StepperLeapfrog< Scalar >

Leapfrog time stepper.

For the governing equation,

$M(t) \ddot{x} + K(t) x = F(t),$

one can write the explicit ODE system,

$\ddot{x} = f(x,t),$

where

$f(x,t) = \left(M(t)\right)^{-1} \left( F(t) - K(t) x \right).$

The Leapfrog stepper can be written as

$\begin{eqnarray*} x_{n+1} & = & x_{n} + \Delta t\, \dot{x}_{n+1/2} \\ \ddot{x}_{n+1} & = & f(x_{n+1},t_{n+1}) \\ \dot{x}_{n+3/2} & = & \dot{x}_{n+1/2} + \Delta t\, \ddot{x}_{n+1} \end{eqnarray*}$

where the position and velocity are leapfrogged over each other. On startup the velocity half-step can be obtained with

$\begin{eqnarray*} \dot{x}_{n+1/2} & = & \dot{x}_{n} + \frac{1}{2} \Delta t\, \ddot{x}_{n} \\ \dot{x}_{n+1/2} & = & \dot{x}_{n} + \frac{1}{2} \Delta t\, f(x_{n},t_{n}) \end{eqnarray*}$

and to complete the time step, the final velocity half-step is obtained with

$\begin{eqnarray*} \dot{x}_{n+1}&=&\dot{x}_{n+1/2} +\frac{1}{2} \Delta t\, \ddot{x}_{n+1} \\ \dot{x}_{n+1}&=&\dot{x}_{n+1/2} +\frac{1}{2} \Delta t\, f(x_{n+1},t_{n+1}) \end{eqnarray*}$

Algorithm

Beginning with $(x_n,\dot{x}_{n+1/2})$ or $(x_n,\dot{x}_{n})$ and/or ending with $(x_{n+1},\dot{x}_{n+3/2})$ or $(x_{n+1},\dot{x}_{n+1})$ , the algorithm for Leapfrog is

if "startup"
- $\ddot{x}_{n} \leftarrow f(x_{n},t_{n})$
- $\dot{x}_{n+1/2} \leftarrow \dot{x}_{n} + \frac{1}{2} \Delta t\, \ddot{x}_{n}$
$x_{n+1} \leftarrow x_{n} + \Delta t\, \dot{x}_{n+1/2}$
$\ddot{x}_{n+1} \leftarrow f(x_{n+1},t_{n+1})$
if "ending"
- $\dot{x}_{n+1} \leftarrow \dot{x}_{n+1/2} +\frac{1}{2} \Delta t\, \ddot{x}_{n+1}$
else
- $\dot{x}_{n+3/2} \leftarrow \dot{x}_{n+1/2} + \Delta t\, \ddot{x}_{n+1}$

The First-Step-As-Last (FSAL) principle is not used with Leapfrog because of the algorithm's prescribed order of solution update. The default is to set useFSAL=false, however useFSAL=true will also work (i.e., no-op), but issue a warning that it will have no affect.

Definition at line 77 of file Tempus_StepperLeapfrog_decl.hpp.

Constructor & Destructor Documentation

template<class Scalar >

Tempus::StepperLeapfrog< Scalar >::StepperLeapfrog ( )

Default constructor.

Requires subsequent setModel() and initialize() calls before calling takeStep().

Definition at line 20 of file Tempus_StepperLeapfrog_impl.hpp.

template<class Scalar >

Tempus::StepperLeapfrog< Scalar >::StepperLeapfrog	(	const Teuchos::RCP< const Thyra::ModelEvaluator< Scalar > > &	appModel,
		const Teuchos::RCP< StepperObserver< Scalar > > &	obs,
		bool	useFSAL,
		std::string	ICConsistency,
		bool	ICConsistencyCheck
	)

Constructor.

Definition at line 32 of file Tempus_StepperLeapfrog_impl.hpp.

Member Function Documentation

template<class Scalar >

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

virtual

Definition at line 195 of file Tempus_StepperLeapfrog_impl.hpp.

template<class Scalar >

Teuchos::RCP< Tempus::StepperState< Scalar > > Tempus::StepperLeapfrog< 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 186 of file Tempus_StepperLeapfrog_impl.hpp.

template<class Scalar >

std::string Tempus::StepperLeapfrog< Scalar >::getICConsistencyDefault ( ) const

inlinevirtual

Reimplemented from Tempus::Stepper< Scalar >.

Definition at line 136 of file Tempus_StepperLeapfrog_decl.hpp.

template<class Scalar >

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

inlinevirtual

Reimplemented from Tempus::StepperExplicit< Scalar >.

Definition at line 120 of file Tempus_StepperLeapfrog_decl.hpp.

template<class Scalar >

virtual Teuchos::RCP<StepperObserver<Scalar> > Tempus::StepperLeapfrog< Scalar >::getObserver ( ) const

inlinevirtual

Get Observer.

Implements Tempus::Stepper< Scalar >.

Definition at line 101 of file Tempus_StepperLeapfrog_decl.hpp.

template<class Scalar >

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

inlinevirtual

Implements Tempus::Stepper< Scalar >.

Definition at line 117 of file Tempus_StepperLeapfrog_decl.hpp.

template<class Scalar >

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

inlinevirtual

Implements Tempus::Stepper< Scalar >.

Definition at line 119 of file Tempus_StepperLeapfrog_decl.hpp.

template<class Scalar >

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

inlinevirtual

Implements Tempus::Stepper< Scalar >.

Definition at line 118 of file Tempus_StepperLeapfrog_decl.hpp.

template<class Scalar >

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

inlinevirtual

Implements Tempus::Stepper< Scalar >.

Definition at line 131 of file Tempus_StepperLeapfrog_decl.hpp.

template<class Scalar >

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

virtual

Implements Tempus::Stepper< Scalar >.

Definition at line 206 of file Tempus_StepperLeapfrog_impl.hpp.

template<class Scalar >

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

virtual

Initialize during construction and after changing input parameters.

Implements Tempus::Stepper< Scalar >.

Definition at line 72 of file Tempus_StepperLeapfrog_impl.hpp.

template<class Scalar >

virtual bool Tempus::StepperLeapfrog< Scalar >::isExplicit ( ) const

inlinevirtual

Reimplemented from Tempus::StepperExplicit< Scalar >.

Definition at line 124 of file Tempus_StepperLeapfrog_decl.hpp.

template<class Scalar >

virtual bool Tempus::StepperLeapfrog< Scalar >::isExplicitImplicit ( ) const

inlinevirtual

Reimplemented from Tempus::StepperExplicit< Scalar >.

Definition at line 126 of file Tempus_StepperLeapfrog_decl.hpp.

template<class Scalar >

virtual bool Tempus::StepperLeapfrog< Scalar >::isImplicit ( ) const

inlinevirtual

Reimplemented from Tempus::StepperExplicit< Scalar >.

Definition at line 125 of file Tempus_StepperLeapfrog_decl.hpp.

template<class Scalar >

virtual bool Tempus::StepperLeapfrog< Scalar >::isMultiStepMethod ( ) const

inlinevirtual

Reimplemented from Tempus::StepperExplicit< Scalar >.

Definition at line 129 of file Tempus_StepperLeapfrog_decl.hpp.

template<class Scalar >

virtual bool Tempus::StepperLeapfrog< Scalar >::isOneStepMethod ( ) const

inlinevirtual

Reimplemented from Tempus::StepperExplicit< Scalar >.

Definition at line 128 of file Tempus_StepperLeapfrog_decl.hpp.

template<class Scalar >

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

virtual

Set the initial conditions and make them consistent.

Reimplemented from Tempus::StepperExplicit< Scalar >.

Definition at line 83 of file Tempus_StepperLeapfrog_impl.hpp.

template<class Scalar >

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

virtual

Set Observer.

Implements Tempus::Stepper< Scalar >.

Definition at line 55 of file Tempus_StepperLeapfrog_impl.hpp.

template<class Scalar >

void Tempus::StepperLeapfrog< 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 108 of file Tempus_StepperLeapfrog_impl.hpp.

Member Data Documentation

template<class Scalar >

Teuchos::RCP<StepperLeapfrogObserver<Scalar> > Tempus::StepperLeapfrog< Scalar >::stepperLFObserver_

protected

Definition at line 147 of file Tempus_StepperLeapfrog_decl.hpp.

template<class Scalar >

Teuchos::RCP<StepperObserverComposite<Scalar> > Tempus::StepperLeapfrog< Scalar >::stepperObserver_

protected

Definition at line 146 of file Tempus_StepperLeapfrog_decl.hpp.

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

http://docs.trilinos.org/r12.18/packages/tempus/src/Tempus_StepperLeapfrog_decl.hpp
http://docs.trilinos.org/r12.18/packages/tempus/src/Tempus_StepperLeapfrog_impl.hpp

Public Member Functions

Protected Attributes

Detailed Description

template<class Scalar> class Tempus::StepperLeapfrog< Scalar >

Constructor & Destructor Documentation

Member Function Documentation

Member Data Documentation

template<class Scalar>
class Tempus::StepperLeapfrog< Scalar >