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Tempus::StepperLeapfrog< Scalar > Class Template Reference

Leapfrog time stepper. More...

#include <Tempus_StepperLeapfrog_decl.hpp>

Inheritance diagram for Tempus::StepperLeapfrog< Scalar >:
Tempus::StepperExplicit< Scalar > Tempus::Stepper< 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
 
virtual bool isValidSetup (Teuchos::FancyOStream &out) 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 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 Teuchos::RCP< const
Thyra::ModelEvaluator< Scalar > > 
getModel ()
 
virtual void setSolver (Teuchos::RCP< Thyra::NonlinearSolverBase< Scalar > > solver)
 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 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 >
virtual void setNonConstModel (const Teuchos::RCP< Thyra::ModelEvaluator< Scalar > > &)
 
virtual void initialize ()
 Initialize after construction and changing input parameters. More...
 
virtual bool isInitialized ()
 True if stepper's member data is initialized. More...
 
virtual void checkInitialized ()
 Check initialization, and error out on failure. More...
 
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 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 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_
 
- Protected Attributes inherited from Tempus::Stepper< Scalar >
bool isInitialized_ = false
 True if stepper's member data is initialized. More...
 

Additional Inherited Members

- Protected Member Functions inherited from Tempus::Stepper< Scalar >
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...
 

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.

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

Reimplemented from Tempus::StepperExplicit< Scalar >.

Definition at line 193 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 184 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 133 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 117 of file Tempus_StepperLeapfrog_decl.hpp.

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

Get Observer.

Reimplemented from 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 114 of file Tempus_StepperLeapfrog_decl.hpp.

template<class Scalar >
virtual Scalar Tempus::StepperLeapfrog< Scalar >::getOrderMax ( ) const
inlinevirtual

Implements Tempus::Stepper< Scalar >.

Definition at line 116 of file Tempus_StepperLeapfrog_decl.hpp.

template<class Scalar >
virtual Scalar Tempus::StepperLeapfrog< Scalar >::getOrderMin ( ) const
inlinevirtual

Implements Tempus::Stepper< Scalar >.

Definition at line 115 of file Tempus_StepperLeapfrog_decl.hpp.

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

Implements Tempus::Stepper< Scalar >.

Definition at line 128 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 226 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 121 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 123 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 122 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 126 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 125 of file Tempus_StepperLeapfrog_decl.hpp.

template<class Scalar >
bool Tempus::StepperLeapfrog< Scalar >::isValidSetup ( Teuchos::FancyOStream &  out) const
virtual

Reimplemented from Tempus::StepperExplicit< Scalar >.

Definition at line 208 of file Tempus_StepperLeapfrog_impl.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 78 of file Tempus_StepperLeapfrog_impl.hpp.

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

Set Observer.

Reimplemented from 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 103 of file Tempus_StepperLeapfrog_impl.hpp.

Member Data Documentation

template<class Scalar >
Teuchos::RCP<StepperLeapfrogObserver<Scalar> > Tempus::StepperLeapfrog< Scalar >::stepperLFObserver_
protected

Definition at line 146 of file Tempus_StepperLeapfrog_decl.hpp.

template<class Scalar >
Teuchos::RCP<StepperObserverComposite<Scalar> > Tempus::StepperLeapfrog< Scalar >::stepperObserver_
protected

Definition at line 145 of file Tempus_StepperLeapfrog_decl.hpp.


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