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Tempus::StepperTrapezoidal< Scalar > Class Template Reference

Trapezoidal method time stepper. More...

#include <Tempus_StepperTrapezoidal_decl.hpp>

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

Public Member Functions

 StepperTrapezoidal ()
 Default constructor.
 
 StepperTrapezoidal (const Teuchos::RCP< const Thyra::ModelEvaluator< Scalar > > &appModel, const Teuchos::RCP< Thyra::NonlinearSolverBase< Scalar > > &solver, bool useFSAL, std::string ICConsistency, bool ICConsistencyCheck, bool zeroInitialGuess, const Teuchos::RCP< StepperTrapezoidalAppAction< Scalar > > &stepperTrapAppAction)
 Constructor.
 
- Public Member Functions inherited from Tempus::StepperImplicit< Scalar >
virtual Teuchos::RCP< const Teuchos::ParameterList > getValidParameters () const override
 
Teuchos::RCP< Teuchos::ParameterList > getValidParametersBasicImplicit () const
 
void setStepperImplicitValues (Teuchos::RCP< Teuchos::ParameterList > pl)
 Set StepperImplicit member data from the ParameterList.
 
void setStepperSolverValues (Teuchos::RCP< Teuchos::ParameterList > pl)
 Set solver from ParameterList.
 
void setSolverName (std::string i)
 Set the Solver Name.
 
std::string getSolverName () const
 Get the Solver Name.
 
virtual void setModel (const Teuchos::RCP< const Thyra::ModelEvaluator< Scalar > > &appModel) override
 Set the model.
 
virtual Teuchos::RCP< const Thyra::ModelEvaluator< Scalar > > getModel () const override
 
virtual Teuchos::RCP< const WrapperModelEvaluator< Scalar > > getWrapperModel ()
 
virtual void setDefaultSolver ()
 
virtual void setSolver (Teuchos::RCP< Thyra::NonlinearSolverBase< Scalar > > solver) override
 Set solver.
 
virtual Teuchos::RCP< Thyra::NonlinearSolverBase< Scalar > > getSolver () const override
 Get solver.
 
const Thyra::SolveStatus< Scalar > solveImplicitODE (const Teuchos::RCP< Thyra::VectorBase< Scalar > > &x, const Teuchos::RCP< Thyra::VectorBase< Scalar > > &xDot, const Scalar time, const Teuchos::RCP< ImplicitODEParameters< Scalar > > &p, const Teuchos::RCP< Thyra::VectorBase< Scalar > > &y=Teuchos::null, const int index=0)
 Solve implicit ODE, f(x, xDot, t, p) = 0.
 
void evaluateImplicitODE (Teuchos::RCP< Thyra::VectorBase< Scalar > > &f, const Teuchos::RCP< Thyra::VectorBase< Scalar > > &x, const Teuchos::RCP< Thyra::VectorBase< Scalar > > &xDot, const Scalar time, const Teuchos::RCP< ImplicitODEParameters< Scalar > > &p)
 Evaluate implicit ODE residual, f(x, xDot, t, p).
 
virtual void setInitialGuess (Teuchos::RCP< const Thyra::VectorBase< Scalar > > initialGuess) override
 Pass initial guess to Newton solver (only relevant for implicit solvers)
 
virtual void setZeroInitialGuess (bool zIG)
 Set parameter so that the initial guess is set to zero (=True) or use last timestep (=False).
 
virtual bool getZeroInitialGuess () const
 
virtual Scalar getInitTimeStep (const Teuchos::RCP< SolutionHistory< Scalar > > &) const override
 
- Public Member Functions inherited from Tempus::Stepper< Scalar >
virtual std::string description () const
 
void setStepperValues (const Teuchos::RCP< Teuchos::ParameterList > pl)
 Set Stepper member data from ParameterList.
 
Teuchos::RCP< Teuchos::ParameterList > getValidParametersBasic () const
 Add basic parameters to Steppers ParameterList.
 
virtual void initialize ()
 Initialize after construction and changing input parameters.
 
virtual bool isInitialized ()
 True if stepper's member data is initialized.
 
virtual void checkInitialized ()
 Check initialization, and error out on failure.
 
void setStepperName (std::string s)
 Set the stepper name.
 
std::string getStepperName () const
 Get the stepper name.
 
std::string getStepperType () const
 Get the stepper type. The stepper type is used as an identifier for the stepper, and can only be set by the derived Stepper class.
 
void setUseFSALTrueOnly (bool a)
 
void setUseFSALFalseOnly (bool a)
 
bool getUseFSAL () const
 
void setICConsistency (std::string s)
 
std::string getICConsistency () const
 
void setICConsistencyCheck (bool c)
 
bool getICConsistencyCheck () const
 
virtual Teuchos::RCP< Thyra::VectorBase< Scalar > > getStepperX ()
 Get Stepper x.
 
virtual Teuchos::RCP< Thyra::VectorBase< Scalar > > getStepperXDot ()
 Get Stepper xDot.
 
virtual Teuchos::RCP< Thyra::VectorBase< Scalar > > getStepperXDotDot ()
 Get Stepper xDotDot.
 
virtual Teuchos::RCP< Thyra::VectorBase< Scalar > > getStepperXDotDot (Teuchos::RCP< SolutionState< Scalar > > state)
 Get xDotDot from SolutionState or Stepper storage.
 

Overridden from Teuchos::Describable

Teuchos::RCP< StepperTrapezoidalAppAction< Scalar > > stepperTrapAppAction_
 
virtual void describe (Teuchos::FancyOStream &out, const Teuchos::EVerbosityLevel verbLevel) const
 
virtual bool isValidSetup (Teuchos::FancyOStream &out) const
 

Basic stepper methods

virtual void setAppAction (Teuchos::RCP< StepperTrapezoidalAppAction< Scalar > > appAction)
 
virtual Teuchos::RCP< StepperTrapezoidalAppAction< Scalar > > getAppAction () const
 
virtual void setInitialConditions (const Teuchos::RCP< SolutionHistory< Scalar > > &solutionHistory)
 Set the initial conditions and make them consistent.
 
virtual void takeStep (const Teuchos::RCP< SolutionHistory< Scalar > > &solutionHistory)
 Take the specified timestep, dt, and return true if successful.
 
virtual Teuchos::RCP< Tempus::StepperState< Scalar > > getDefaultStepperState ()
 Get a default (initial) StepperState.
 
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 setUseFSAL (bool a)
 
virtual OrderODE getOrderODE () const
 
virtual Scalar getAlpha (const Scalar dt) const
 Return alpha = d(xDot)/dx.
 
virtual Scalar getBeta (const Scalar) const
 Return beta = d(x)/dx.
 

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.
 
virtual void setStepperXDot (Teuchos::RCP< Thyra::VectorBase< Scalar > > xDot)
 Set xDot for Stepper storage.
 
virtual void setStepperXDotDot (Teuchos::RCP< Thyra::VectorBase< Scalar > > xDotDot)
 Set x for Stepper storage.
 
void setStepperType (std::string s)
 Set the stepper type.
 
- Protected Attributes inherited from Tempus::StepperImplicit< Scalar >
Teuchos::RCP< WrapperModelEvaluator< Scalar > > wrapperModel_
 
Teuchos::RCP< Thyra::NonlinearSolverBase< Scalar > > solver_
 
Teuchos::RCP< const Thyra::VectorBase< Scalar > > initialGuess_
 
bool zeroInitialGuess_
 
std::string solverName_
 
- Protected Attributes inherited from Tempus::Stepper< Scalar >
bool useFSAL_ = false
 Use First-Same-As-Last (FSAL) principle.
 
bool isInitialized_ = false
 True if stepper's member data is initialized.
 

Detailed Description

template<class Scalar>
class Tempus::StepperTrapezoidal< Scalar >

Trapezoidal method time stepper.

For the implicit ODE system, $\mathcal{F}(\dot{x},x,t) = 0$, the solution, $\dot{x}$ and $x$, is determined using a solver (e.g., a non-linear solver, like NOX).

Algorithm The single-timestep algorithm for Trapezoidal is

\begin{center}
  \parbox{5in}{
  \rule{5in}{0.4pt} \\
  {\bf Algorithm} Trapezoidal \\
  \rule{5in}{0.4pt} \vspace{-15pt}
  \begin{enumerate}
    \setlength{\itemsep}{0pt} \setlength{\parskip}{0pt} \setlength{\parsep}{0pt}
    \item {\it appAction.execute(solutionHistory, stepper, BEGIN\_STEP)}
    \item {\bf Set ODE parameters.}
    \item \quad {\bf Time derivative: }
                $\dot{x}_{n} = \frac{(x_{n} - x_{n-1})}{(\Delta t_n/2)} - \dot{x}_{n-1}.$
    \item \quad {\bf Alpha: $\alpha = \frac{2}{\Delta t_n}$}
    \item \quad {\bf Beta: $\beta = 1$}
    \item {\it appAction.execute(solutionHistory, stepper, BEFORE\_SOLVE)}
    \item {\bf Solve $\mathcal{F}_n(\dot{x}=(x_n-x_{n-1})/(\Delta t_n/2) - \dot{x}_{n-1}, x_n, t_n)=0$ for $x_n$}
    \item {\it appAction.execute(solutionHistory, stepper, AFTER\_SOLVE)}
    \item $\dot{x}_n \leftarrow (x_n-x_{n-1})/(\Delta t_n/2) - \dot{x}_{n-1}$
    \item {\it appAction.execute(solutionHistory, stepper, END\_STEP)}
  \end{enumerate}
  \vspace{-10pt} \rule{5in}{0.4pt}
  }
\end{center}

The First-Same-As-Last (FSAL) principle is required for the Trapezoidal Stepper (i.e., useFSAL=true)! With useFSAL=true does assume that the solution, $x$, and its time derivative, $\dot{x}$, are consistent at the initial conditions (ICs), i.e., $\dot{x}_{0} = \bar{f}(x_{0},t_{0})$. This can be ensured by setting setICConsistency("Consistent"), and checked with setICConsistencyCheck(true).

Iteration Matrix, $W$. Recalling that the definition of the iteration matrix, $W$, is

\[
  W = \alpha \frac{\partial \mathcal{F}_n}{\partial \dot{x}_n}
    + \beta  \frac{\partial \mathcal{F}_n}{\partial x_n},
\]

where $ \alpha \equiv \frac{\partial \dot{x}_n(x_n) }{\partial x_n}, $ and $ \beta \equiv \frac{\partial x_n}{\partial x_n} = 1$, and the time derivative for Trapezoidal method is

\[
  \dot{x}_n = (x_n-x_{n-1})/(\Delta t/2) - \dot{x}_{n-1},
\]

we can determine that $ \alpha = \frac{2}{\Delta t} $ and $ \beta = 1 $, and therefore write

\[
  W = \frac{2}{\Delta t}
      \frac{\partial \mathcal{F}_n}{\partial \dot{x}_n}
    + \frac{\partial \mathcal{F}_n}{\partial x_n}.
\]

Definition at line 83 of file Tempus_StepperTrapezoidal_decl.hpp.

Constructor & Destructor Documentation

◆ StepperTrapezoidal() [1/2]

template<class Scalar >
Tempus::StepperTrapezoidal< Scalar >::StepperTrapezoidal ( )

Default constructor.

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

Definition at line 20 of file Tempus_StepperTrapezoidal_impl.hpp.

◆ StepperTrapezoidal() [2/2]

template<class Scalar >
Tempus::StepperTrapezoidal< Scalar >::StepperTrapezoidal ( const Teuchos::RCP< const Thyra::ModelEvaluator< Scalar > > & appModel,
const Teuchos::RCP< Thyra::NonlinearSolverBase< Scalar > > & solver,
bool useFSAL,
std::string ICConsistency,
bool ICConsistencyCheck,
bool zeroInitialGuess,
const Teuchos::RCP< StepperTrapezoidalAppAction< Scalar > > & stepperTrapAppAction )

Constructor.

Definition at line 35 of file Tempus_StepperTrapezoidal_impl.hpp.

Member Function Documentation

◆ setAppAction()

template<class Scalar >
void Tempus::StepperTrapezoidal< Scalar >::setAppAction ( Teuchos::RCP< StepperTrapezoidalAppAction< Scalar > > appAction)
virtual

Definition at line 62 of file Tempus_StepperTrapezoidal_impl.hpp.

◆ getAppAction()

template<class Scalar >
virtual Teuchos::RCP< StepperTrapezoidalAppAction< Scalar > > Tempus::StepperTrapezoidal< Scalar >::getAppAction ( ) const
inlinevirtual

Definition at line 109 of file Tempus_StepperTrapezoidal_decl.hpp.

◆ setInitialConditions()

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

Set the initial conditions and make them consistent.

Reimplemented from Tempus::StepperImplicit< Scalar >.

Definition at line 77 of file Tempus_StepperTrapezoidal_impl.hpp.

◆ takeStep()

template<class Scalar >
void Tempus::StepperTrapezoidal< 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 106 of file Tempus_StepperTrapezoidal_impl.hpp.

◆ getDefaultStepperState()

template<class Scalar >
Teuchos::RCP< Tempus::StepperState< Scalar > > Tempus::StepperTrapezoidal< 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 177 of file Tempus_StepperTrapezoidal_impl.hpp.

◆ getOrder()

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

Implements Tempus::Stepper< Scalar >.

Definition at line 122 of file Tempus_StepperTrapezoidal_decl.hpp.

◆ getOrderMin()

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

Implements Tempus::Stepper< Scalar >.

Definition at line 123 of file Tempus_StepperTrapezoidal_decl.hpp.

◆ getOrderMax()

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

Implements Tempus::Stepper< Scalar >.

Definition at line 124 of file Tempus_StepperTrapezoidal_decl.hpp.

◆ isExplicit()

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

Implements Tempus::Stepper< Scalar >.

Definition at line 126 of file Tempus_StepperTrapezoidal_decl.hpp.

◆ isImplicit()

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

Implements Tempus::Stepper< Scalar >.

Definition at line 127 of file Tempus_StepperTrapezoidal_decl.hpp.

◆ isExplicitImplicit()

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

Implements Tempus::Stepper< Scalar >.

Definition at line 128 of file Tempus_StepperTrapezoidal_decl.hpp.

◆ isOneStepMethod()

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

Implements Tempus::Stepper< Scalar >.

Definition at line 130 of file Tempus_StepperTrapezoidal_decl.hpp.

◆ isMultiStepMethod()

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

Implements Tempus::Stepper< Scalar >.

Definition at line 131 of file Tempus_StepperTrapezoidal_decl.hpp.

◆ setUseFSAL()

template<class Scalar >
virtual void Tempus::StepperTrapezoidal< Scalar >::setUseFSAL ( bool a)
inlinevirtual

Reimplemented from Tempus::Stepper< Scalar >.

Definition at line 132 of file Tempus_StepperTrapezoidal_decl.hpp.

◆ getOrderODE()

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

Implements Tempus::Stepper< Scalar >.

Definition at line 133 of file Tempus_StepperTrapezoidal_decl.hpp.

◆ getAlpha()

template<class Scalar >
virtual Scalar Tempus::StepperTrapezoidal< Scalar >::getAlpha ( const Scalar dt) const
inlinevirtual

Return alpha = d(xDot)/dx.

Implements Tempus::StepperImplicit< Scalar >.

Definition at line 137 of file Tempus_StepperTrapezoidal_decl.hpp.

◆ getBeta()

template<class Scalar >
virtual Scalar Tempus::StepperTrapezoidal< Scalar >::getBeta ( const Scalar ) const
inlinevirtual

Return beta = d(x)/dx.

Implements Tempus::StepperImplicit< Scalar >.

Definition at line 139 of file Tempus_StepperTrapezoidal_decl.hpp.

◆ describe()

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

Reimplemented from Tempus::StepperImplicit< Scalar >.

Definition at line 187 of file Tempus_StepperTrapezoidal_impl.hpp.

◆ isValidSetup()

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

Reimplemented from Tempus::StepperImplicit< Scalar >.

Definition at line 203 of file Tempus_StepperTrapezoidal_impl.hpp.

Member Data Documentation

◆ stepperTrapAppAction_

template<class Scalar >
Teuchos::RCP<StepperTrapezoidalAppAction<Scalar> > Tempus::StepperTrapezoidal< Scalar >::stepperTrapAppAction_
private

Definition at line 152 of file Tempus_StepperTrapezoidal_decl.hpp.


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