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Tempus::StepperBDF2< Scalar > Class Template Reference

BDF2 (Backward-Difference-Formula-2) time stepper. More...

#include <Tempus_StepperBDF2_decl.hpp>

Inheritance diagram for Tempus::StepperBDF2< Scalar >:
Tempus::StepperImplicit< Scalar > Tempus::Stepper< Scalar >

Public Member Functions

 StepperBDF2 (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...
 
void setStartUpStepper (std::string startupStepperName)
 Set the stepper to use in first step. More...
 
void setStartUpStepper (Teuchos::RCP< Teuchos::ParameterList >startUpStepperPL=Teuchos::null)
 Set the start up stepper to the supplied Parameter sublist. More...
 
virtual void initialize ()
 Initialize during construction and after changing input parameters. 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 bool isExplicit () const
 
virtual bool isImplicit () const
 
virtual bool isExplicitImplicit () const
 
virtual bool isOneStepMethod () const
 
virtual bool isMultiStepMethod () const
 
virtual void computeStartUp (const Teuchos::RCP< SolutionHistory< Scalar > > &solutionHistory)
 Compute the first time step given the supplied startup stepper. More...
 
virtual void setInitialGuess (Teuchos::RCP< const Thyra::VectorBase< Scalar > > initial_guess)
 Pass initial guess to Newton solver. More...
 
virtual Teuchos::RCP< Thyra::VectorBase< Scalar > > getXDotTemp (Teuchos::RCP< Thyra::VectorBase< Scalar > > x)
 Provide temporary xDot memory for Stepper if SolutionState doesn't. More...
 
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
 
- Public Member Functions inherited from Tempus::StepperImplicit< 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 (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
 
const Thyra::SolveStatus< Scalar > solveImplicitODE (const Teuchos::RCP< Thyra::VectorBase< Scalar > > &x)
 Solve problem using x in-place. More...
 
virtual void setZeroInitialGuess (bool zIG)
 Set parameter so that the initial guess is set to zero (=True) or use last timestep (=False). More...
 
virtual bool getZeroInitialGuess () const
 
virtual bool getEmbedded () const
 
virtual Scalar getInitTimeStep (const Teuchos::RCP< SolutionHistory< Scalar > > &solutionHistory) const
 
- Public Member Functions inherited from Tempus::Stepper< Scalar >
virtual void createSubSteppers (std::vector< Teuchos::RCP< const Thyra::ModelEvaluator< Scalar > > > models)
 
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
 

Overridden from Teuchos::Describable

Teuchos::RCP< Stepper< Scalar > > startUpStepper_
 
Teuchos::RCP< StepperObserver< Scalar > > stepperObserver_
 
Teuchos::RCP< StepperBDF2Observer< Scalar > > stepperBDF2Observer_
 
Scalar order_
 
Teuchos::RCP< Thyra::VectorBase< Scalar > > xDotTemp_
 
Teuchos::RCP< const Thyra::VectorBase< Scalar > > initial_guess_
 
virtual std::string description () const
 
virtual void describe (Teuchos::FancyOStream &out, const Teuchos::EVerbosityLevel verbLevel) const
 
 StepperBDF2 ()
 Default Constructor – not allowed. More...
 

Additional Inherited Members

- Protected Attributes inherited from Tempus::StepperImplicit< Scalar >
Teuchos::RCP< Teuchos::ParameterList > stepperPL_
 
Teuchos::RCP< WrapperModelEvaluator< Scalar > > wrapperModel_
 
Teuchos::RCP< Thyra::NonlinearSolverBase< Scalar > > solver_
 
Teuchos::RCP< const Thyra::VectorBase< Scalar > > initial_guess_
 

Detailed Description

template<class Scalar>
class Tempus::StepperBDF2< Scalar >

BDF2 (Backward-Difference-Formula-2) time stepper.

For the implicit ODE system, $f(\dot{x},x,t) = 0$, the solution, $\dot{x}$ and $x$, is determined using a solver (e.g., a non-linear solver, like NOX). This stepper allows for a variable time-step $dt$. It is a 3-step method.

Algorithm

  • Select initial guess $x_n$ for $n$.
  • Compute $x_n$ for n=1 using some time-integration scheme, e.g., Backward Euler or RK4.
  • Solve

    \[ f\left(\dot{x} = \frac{x_{n-1}-x_{n-2}}{\tau_{n-1}} + \left(\frac{1}{\tau_{n-1}-\tau_n} \right) \left(\frac{x_n-x_{n-1}}{\tau_{n-1} + \tau_n} - \frac{x_{n-1}-x_{n-2}}{\tau_{n-1}}\right) (2\tau_n + \tau_{n-1}), x_n, t_n\right) = 0 \]

    for $x_n$ (n > 1) where

    \[ \tau_n = t_n - t_{n-1}. \]

Definition at line 44 of file Tempus_StepperBDF2_decl.hpp.

Constructor & Destructor Documentation

◆ StepperBDF2() [1/2]

template<class Scalar >
Tempus::StepperBDF2< Scalar >::StepperBDF2 ( const Teuchos::RCP< const Thyra::ModelEvaluator< Scalar > > &  appModel,
Teuchos::RCP< Teuchos::ParameterList >  pList = Teuchos::null 
)

Constructor.

Definition at line 27 of file Tempus_StepperBDF2_impl.hpp.

◆ StepperBDF2() [2/2]

template<class Scalar>
Tempus::StepperBDF2< Scalar >::StepperBDF2 ( )
private

Default Constructor – not allowed.

Member Function Documentation

◆ computeStartUp()

template<class Scalar >
void Tempus::StepperBDF2< Scalar >::computeStartUp ( const Teuchos::RCP< SolutionHistory< Scalar > > &  solutionHistory)
virtual

Compute the first time step given the supplied startup stepper.

Definition at line 258 of file Tempus_StepperBDF2_impl.hpp.

◆ describe()

template<class Scalar >
void Tempus::StepperBDF2< Scalar >::describe ( Teuchos::FancyOStream &  out,
const Teuchos::EVerbosityLevel  verbLevel 
) const
virtual

Definition at line 298 of file Tempus_StepperBDF2_impl.hpp.

◆ description()

template<class Scalar >
std::string Tempus::StepperBDF2< Scalar >::description ( ) const
virtual

Definition at line 290 of file Tempus_StepperBDF2_impl.hpp.

◆ getDefaultParameters()

template<class Scalar >
Teuchos::RCP< Teuchos::ParameterList > Tempus::StepperBDF2< Scalar >::getDefaultParameters ( ) const
virtual

Implements Tempus::Stepper< Scalar >.

Definition at line 353 of file Tempus_StepperBDF2_impl.hpp.

◆ getDefaultStepperState()

template<class Scalar >
Teuchos::RCP< Tempus::StepperState< Scalar > > Tempus::StepperBDF2< 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 281 of file Tempus_StepperBDF2_impl.hpp.

◆ getNonconstParameterList()

template<class Scalar >
Teuchos::RCP< Teuchos::ParameterList > Tempus::StepperBDF2< Scalar >::getNonconstParameterList ( )

Definition at line 373 of file Tempus_StepperBDF2_impl.hpp.

◆ getOrder()

template<class Scalar>
virtual Scalar Tempus::StepperBDF2< Scalar >::getOrder ( ) const
inlinevirtual

Implements Tempus::Stepper< Scalar >.

Definition at line 71 of file Tempus_StepperBDF2_decl.hpp.

◆ getOrderMax()

template<class Scalar>
virtual Scalar Tempus::StepperBDF2< Scalar >::getOrderMax ( ) const
inlinevirtual

Implements Tempus::Stepper< Scalar >.

Definition at line 73 of file Tempus_StepperBDF2_decl.hpp.

◆ getOrderMin()

template<class Scalar>
virtual Scalar Tempus::StepperBDF2< Scalar >::getOrderMin ( ) const
inlinevirtual

Implements Tempus::Stepper< Scalar >.

Definition at line 72 of file Tempus_StepperBDF2_decl.hpp.

◆ getValidParameters()

template<class Scalar >
Teuchos::RCP< const Teuchos::ParameterList > Tempus::StepperBDF2< Scalar >::getValidParameters ( ) const

Definition at line 338 of file Tempus_StepperBDF2_impl.hpp.

◆ getXDotTemp()

template<class Scalar >
Teuchos::RCP< Thyra::VectorBase< Scalar > > Tempus::StepperBDF2< Scalar >::getXDotTemp ( Teuchos::RCP< Thyra::VectorBase< Scalar > >  x)
virtual

Provide temporary xDot memory for Stepper if SolutionState doesn't.

Definition at line 248 of file Tempus_StepperBDF2_impl.hpp.

◆ initialize()

template<class Scalar >
void Tempus::StepperBDF2< Scalar >::initialize ( )
virtual

Initialize during construction and after changing input parameters.

Implements Tempus::Stepper< Scalar >.

Definition at line 143 of file Tempus_StepperBDF2_impl.hpp.

◆ isExplicit()

template<class Scalar>
virtual bool Tempus::StepperBDF2< Scalar >::isExplicit ( ) const
inlinevirtual

Implements Tempus::Stepper< Scalar >.

Definition at line 75 of file Tempus_StepperBDF2_decl.hpp.

◆ isExplicitImplicit()

template<class Scalar>
virtual bool Tempus::StepperBDF2< Scalar >::isExplicitImplicit ( ) const
inlinevirtual

Implements Tempus::Stepper< Scalar >.

Definition at line 77 of file Tempus_StepperBDF2_decl.hpp.

◆ isImplicit()

template<class Scalar>
virtual bool Tempus::StepperBDF2< Scalar >::isImplicit ( ) const
inlinevirtual

Implements Tempus::Stepper< Scalar >.

Definition at line 76 of file Tempus_StepperBDF2_decl.hpp.

◆ isMultiStepMethod()

template<class Scalar>
virtual bool Tempus::StepperBDF2< Scalar >::isMultiStepMethod ( ) const
inlinevirtual

Implements Tempus::Stepper< Scalar >.

Definition at line 80 of file Tempus_StepperBDF2_decl.hpp.

◆ isOneStepMethod()

template<class Scalar>
virtual bool Tempus::StepperBDF2< Scalar >::isOneStepMethod ( ) const
inlinevirtual

Implements Tempus::Stepper< Scalar >.

Definition at line 79 of file Tempus_StepperBDF2_decl.hpp.

◆ setInitialGuess()

template<class Scalar>
virtual void Tempus::StepperBDF2< Scalar >::setInitialGuess ( Teuchos::RCP< const Thyra::VectorBase< Scalar > >  initial_guess)
inlinevirtual

Pass initial guess to Newton solver.

Reimplemented from Tempus::StepperImplicit< Scalar >.

Definition at line 88 of file Tempus_StepperBDF2_decl.hpp.

◆ setObserver()

template<class Scalar >
void Tempus::StepperBDF2< Scalar >::setObserver ( Teuchos::RCP< StepperObserver< Scalar > >  obs = Teuchos::null)
virtual

Set Observer.

Implements Tempus::Stepper< Scalar >.

Definition at line 122 of file Tempus_StepperBDF2_impl.hpp.

◆ setParameterList()

template<class Scalar >
void Tempus::StepperBDF2< Scalar >::setParameterList ( const Teuchos::RCP< Teuchos::ParameterList > &  pl)

Definition at line 308 of file Tempus_StepperBDF2_impl.hpp.

◆ setStartUpStepper() [1/2]

template<class Scalar >
void Tempus::StepperBDF2< Scalar >::setStartUpStepper ( std::string  startupStepperName)

Set the stepper to use in first step.

Set the startup stepper to a pre-defined stepper in the ParameterList.

The startup stepper is set to stepperName sublist in the Stepper's ParameterList. The stepperName sublist should already be defined in the Stepper's ParameterList. Otherwise it will fail.

Definition at line 48 of file Tempus_StepperBDF2_impl.hpp.

◆ setStartUpStepper() [2/2]

template<class Scalar >
void Tempus::StepperBDF2< Scalar >::setStartUpStepper ( Teuchos::RCP< Teuchos::ParameterList >  startupStepperPL = Teuchos::null)

Set the start up stepper to the supplied Parameter sublist.

This adds a new start up stepper Parameter sublist to the Stepper's ParameterList. If the start up stepper sublist is null, it tests if the stepper sublist is set in the Stepper's ParameterList.

Definition at line 69 of file Tempus_StepperBDF2_impl.hpp.

◆ takeStep()

template<class Scalar >
void Tempus::StepperBDF2< 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 159 of file Tempus_StepperBDF2_impl.hpp.

◆ unsetParameterList()

template<class Scalar >
Teuchos::RCP< Teuchos::ParameterList > Tempus::StepperBDF2< Scalar >::unsetParameterList ( )

Definition at line 381 of file Tempus_StepperBDF2_impl.hpp.

Member Data Documentation

◆ initial_guess_

template<class Scalar>
Teuchos::RCP<const Thyra::VectorBase<Scalar> > Tempus::StepperBDF2< Scalar >::initial_guess_
private

Definition at line 126 of file Tempus_StepperBDF2_decl.hpp.

◆ order_

template<class Scalar>
Scalar Tempus::StepperBDF2< Scalar >::order_
private

Definition at line 123 of file Tempus_StepperBDF2_decl.hpp.

◆ startUpStepper_

template<class Scalar>
Teuchos::RCP<Stepper<Scalar> > Tempus::StepperBDF2< Scalar >::startUpStepper_
private

Definition at line 119 of file Tempus_StepperBDF2_decl.hpp.

◆ stepperBDF2Observer_

template<class Scalar>
Teuchos::RCP<StepperBDF2Observer<Scalar> > Tempus::StepperBDF2< Scalar >::stepperBDF2Observer_
private

Definition at line 122 of file Tempus_StepperBDF2_decl.hpp.

◆ stepperObserver_

template<class Scalar>
Teuchos::RCP<StepperObserver<Scalar> > Tempus::StepperBDF2< Scalar >::stepperObserver_
private

Definition at line 121 of file Tempus_StepperBDF2_decl.hpp.

◆ xDotTemp_

template<class Scalar>
Teuchos::RCP<Thyra::VectorBase<Scalar> > Tempus::StepperBDF2< Scalar >::xDotTemp_
private

Definition at line 125 of file Tempus_StepperBDF2_decl.hpp.

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