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Tempus::StepperDIRK< Scalar > Class Template Referenceabstract

Diagonally Implicit Runge-Kutta (DIRK) time stepper. More...

#include <Tempus_StepperDIRK_decl.hpp>

Inheritance diagram for Tempus::StepperDIRK< Scalar >:
Tempus::StepperImplicit< Scalar > Tempus::Stepper< Scalar > Tempus::StepperDIRK_1Stage1stOrderRadauIA< Scalar > Tempus::StepperDIRK_1StageTheta< Scalar > Tempus::StepperDIRK_2Stage2ndOrderLobattoIIIB< Scalar > Tempus::StepperDIRK_BackwardEuler< Scalar > Tempus::StepperDIRK_General< Scalar > Tempus::StepperEDIRK_2Stage3rdOrder< Scalar > Tempus::StepperEDIRK_2StageTheta< Scalar > Tempus::StepperEDIRK_TrapezoidalRule< Scalar > Tempus::StepperSDIRK_21Pair< Scalar > Tempus::StepperSDIRK_2Stage2ndOrder< Scalar > Tempus::StepperSDIRK_2Stage3rdOrder< Scalar > Tempus::StepperSDIRK_3Stage4thOrder< Scalar > Tempus::StepperSDIRK_5Stage4thOrder< Scalar > Tempus::StepperSDIRK_5Stage5thOrder< Scalar > Tempus::StepperSDIRK_ImplicitMidpoint< Scalar >

Public Member Functions

virtual Scalar getAlpha (const Scalar dt) const
 Return alpha = d(xDot)/dx. More...
 
virtual Scalar getBeta (const Scalar) const
 Return beta = d(x)/dx. More...
 
Teuchos::RCP< const
Teuchos::ParameterList > 
getValidParameters () const
 
Basic stepper methods
virtual void setObserver (Teuchos::RCP< StepperObserver< Scalar > > obs=Teuchos::null)
 Set Observer. More...
 
virtual Teuchos::RCP< const
RKButcherTableau< Scalar > > 
getTableau ()
 
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 setResetInitialGuess (bool reset_guess)
 Set parameter so that the initial guess is reset at the beginning of each timestep. More...
 
virtual bool getResetInitialGuess () const
 
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 OrderODE getOrderODE () const
 
void getValidParametersBasicDIRK (Teuchos::RCP< Teuchos::ParameterList > pl) const
 
virtual std::string getDescription () const =0
 
Overridden from Teuchos::Describable
virtual void describe (Teuchos::FancyOStream &out, const Teuchos::EVerbosityLevel verbLevel) const
 
Accessors methods
virtual void setUseEmbedded (bool a)
 Use embedded if avialable. More...
 
virtual bool getUseEmbedded () const
 
virtual bool getUseEmbeddedDefault () 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 Teuchos::RCP< const
WrapperModelEvaluator< Scalar > > 
getWrapperModel ()
 
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...
 
const Thyra::SolveStatus< Scalar > solveImplicitODE (const Teuchos::RCP< Thyra::VectorBase< Scalar > > &x)
 Solve problem using x in-place. (Needs to be deprecated!) More...
 
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)
 Solve implicit ODE, f(x, xDot, t, p) = 0. More...
 
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). More...
 
virtual void setInitialGuess (Teuchos::RCP< const Thyra::VectorBase< Scalar > > initial_guess)
 Pass initial guess to Newton solver (only relevant for implicit solvers) 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 Scalar getInitTimeStep (const Teuchos::RCP< SolutionHistory< Scalar > > &) const
 
virtual void setStepperXDot (Teuchos::RCP< Thyra::VectorBase< Scalar > > xDot)
 Set xDot for 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...
 
- 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
 
virtual std::string getICConsistencyDefault () 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 Member Functions

virtual void setupDefault ()
 Default setup for constructor. More...
 
virtual void setup (const Teuchos::RCP< const Thyra::ModelEvaluator< Scalar > > &wrapperModel, const Teuchos::RCP< StepperRKObserver< Scalar > > &obs, const Teuchos::RCP< Thyra::NonlinearSolverBase< Scalar > > &solver, bool useFSAL, std::string ICConsistency, bool ICConsistencyCheck, bool useEmbedded, bool zeroInitialGuess)
 Setup for constructor. More...
 
virtual void setupTableau ()=0
 

Protected Attributes

Teuchos::RCP< RKButcherTableau
< Scalar > > 
tableau_
 
std::vector< Teuchos::RCP
< Thyra::VectorBase< Scalar > > > 
stageXDot_
 
Teuchos::RCP
< Thyra::VectorBase< Scalar > > 
stageX_
 
Teuchos::RCP
< Thyra::VectorBase< Scalar > > 
xTilde_
 
Teuchos::RCP
< StepperRKObserverComposite
< Scalar > > 
stepperObserver_
 
bool useEmbedded_
 
Teuchos::RCP
< Thyra::VectorBase< Scalar > > 
ee_
 
Teuchos::RCP
< Thyra::VectorBase< Scalar > > 
abs_u0
 
Teuchos::RCP
< Thyra::VectorBase< Scalar > > 
abs_u
 
Teuchos::RCP
< Thyra::VectorBase< Scalar > > 
sc
 
bool resetGuess_ = true
 
- Protected Attributes inherited from Tempus::StepperImplicit< Scalar >
Teuchos::RCP
< WrapperModelEvaluator
< Scalar > > 
wrapperModel_
 
Teuchos::RCP
< Thyra::NonlinearSolverBase
< Scalar > > 
solver_
 
Teuchos::RCP< const
Thyra::VectorBase< Scalar > > 
initial_guess_
 
bool zeroInitialGuess_
 
Teuchos::RCP< StepperObserver
< Scalar > > 
stepperObserver_
 
Teuchos::RCP
< Thyra::VectorBase< Scalar > > 
stepperXDot_
 
Teuchos::RCP
< Thyra::VectorBase< Scalar > > 
stepperXDotDot_
 

Detailed Description

template<class Scalar>
class Tempus::StepperDIRK< Scalar >

Diagonally Implicit Runge-Kutta (DIRK) time stepper.

For the implicit ODE system, $\mathcal{F}(\dot{x},x,t) = 0$, the general DIRK method for $s$-stages, can be written as

\[ X_{i} = x_{n-1} + \Delta t\,\sum_{j=1}^{i-1} a_{ij}\,\bar{f}(X_{j},t_{n-1}+c_{j}\Delta t) + \Delta t\, a_{ii}\,\bar{f}(X_{i},t_{n-1}+c_{i}\Delta t) \]

\[ x_{n} = x_{n-1} + \Delta t\,\sum_{i=1}^{s}b_{i}\,\bar{f}(X_{i},t_{n-1}+c_{i}\Delta t) \]

where $\dot{x}=\bar{f}(x,t)$ is the explicit form of the ODE, $X_{i}$ are intermediate approximations to the solution at times, $t_{n-1}+c_{i}\Delta t$, (stage solutions) which may be correct to a lower order of accuracy than the solution, $x_{n}$. We should note that these lower-order approximations are combined through $b_{i}$ so that error terms cancel out and produce a more accurate solution. Note for DIRK methods that $a_{ii}=a$ for all the diagonal components is referred to as Singly Diagonal Implicit Runge-Kutta (SDIRK) methods.

Note that the stage time derivatives,

\[ \dot{X}_{i} = \bar{f}(X_{i},t_{n-1}+c_{i}\Delta t), \]

can be found via

\begin{eqnarray*} \dot{X}_{i} & = & \frac{1}{a_{ii} \Delta t} [ X_{i} - x_{n-1} - \Delta t\,\sum_{j=1}^{i-1} a_{ij}\,\dot{X}_{j} ] \\ \dot{X}_{i} & = & \frac{X_{i} - \tilde{X}}{a_{ii} \Delta t} \end{eqnarray*}

where

\[ \tilde{X} = x_{n-1} + \Delta t \sum_{j=1}^{i-1} a_{ij}\, \dot{X}_{j} \]

Recalling that the definition for a DIRK is that for $j>i$, $a_{ij} = 0$ and $a_{ii} \neq 0$ for at least one $i$. Thus for stages where $a_{ii} = 0$, we can use the explicit RK methods (see StepperExplicitRK for additional details).

Algorithm The single-timestep algorithm for DIRK is,

  • for $i = 1 \ldots s$ do
    • if $a_{ii} = 0$
      • $X_i \leftarrow x_{n-1} + \Delta t\,\sum_{j=1}^{i-1} a_{ij}\,\dot{X}_j$
      • Evaluate $\bar{f}(X_{i},t_{n-1}+c_{i}\Delta t)$
      • $\dot{X}_i \leftarrow \bar{f}(X_i,t_{n-1}+c_i\Delta t)$
    • else
      • $\tilde{X} = x_{n-1} +\Delta t \sum_{j=1}^{i-1} a_{ij}\,\dot{X}_{j}$
      • Define $\dot{X}_i \leftarrow \frac{X_{i} - \tilde{X}}{a_{ii} \Delta t}$
      • Solve $f(\dot{x} = \dot{X}_i,X_i,t_{n-1}+c_{i}\Delta t)=0$ for $X_i$
      • $\dot{X}_i \leftarrow \frac{X_{i} - \tilde{X}}{a_{ii} \Delta t}$
  • end for
  • $x_n \leftarrow x_{n-1} + \Delta t\,\sum_{i=1}^{s}b_i\,\dot{X}_i$

The First-Step-As-Last (FSAL) principle is not needed with DIRK, but maybe useful if the first stage is explicit (i.e, EDIRK). The default is to set useFSAL=false.

Definition at line 87 of file Tempus_StepperDIRK_decl.hpp.

Member Function Documentation

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

Definition at line 352 of file Tempus_StepperDIRK_impl.hpp.

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

Return alpha = d(xDot)/dx.

Implements Tempus::StepperImplicit< Scalar >.

Definition at line 148 of file Tempus_StepperDIRK_decl.hpp.

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

Return beta = d(x)/dx.

Implements Tempus::StepperImplicit< Scalar >.

Definition at line 154 of file Tempus_StepperDIRK_decl.hpp.

template<class Scalar >
Teuchos::RCP< Tempus::StepperState< Scalar > > Tempus::StepperDIRK< 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 343 of file Tempus_StepperDIRK_impl.hpp.

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

Get Observer.

Implements Tempus::Stepper< Scalar >.

Definition at line 99 of file Tempus_StepperDIRK_decl.hpp.

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

Implements Tempus::Stepper< Scalar >.

Definition at line 121 of file Tempus_StepperDIRK_decl.hpp.

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

Implements Tempus::Stepper< Scalar >.

Definition at line 123 of file Tempus_StepperDIRK_decl.hpp.

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

Implements Tempus::Stepper< Scalar >.

Definition at line 122 of file Tempus_StepperDIRK_decl.hpp.

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

Implements Tempus::Stepper< Scalar >.

Definition at line 139 of file Tempus_StepperDIRK_decl.hpp.

template<class Scalar >
virtual bool Tempus::StepperDIRK< Scalar >::getResetInitialGuess ( ) const
inlinevirtual

Definition at line 112 of file Tempus_StepperDIRK_decl.hpp.

template<class Scalar >
virtual Teuchos::RCP<const RKButcherTableau<Scalar> > Tempus::StepperDIRK< Scalar >::getTableau ( )
inlinevirtual

Definition at line 96 of file Tempus_StepperDIRK_decl.hpp.

template<class Scalar >
virtual bool Tempus::StepperDIRK< Scalar >::getUseEmbedded ( ) const
inlinevirtual

Definition at line 168 of file Tempus_StepperDIRK_decl.hpp.

template<class Scalar >
virtual bool Tempus::StepperDIRK< Scalar >::getUseEmbeddedDefault ( ) const
inlinevirtual

Definition at line 169 of file Tempus_StepperDIRK_decl.hpp.

template<class Scalar >
void Tempus::StepperDIRK< Scalar >::getValidParametersBasicDIRK ( Teuchos::RCP< Teuchos::ParameterList >  pl) const

Definition at line 67 of file Tempus_StepperDIRK_impl.hpp.

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

Initialize during construction and after changing input parameters.

Implements Tempus::Stepper< Scalar >.

Definition at line 116 of file Tempus_StepperDIRK_impl.hpp.

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

Implements Tempus::Stepper< Scalar >.

Definition at line 125 of file Tempus_StepperDIRK_decl.hpp.

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

Implements Tempus::Stepper< Scalar >.

Definition at line 134 of file Tempus_StepperDIRK_decl.hpp.

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

Implements Tempus::Stepper< Scalar >.

Definition at line 133 of file Tempus_StepperDIRK_decl.hpp.

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

Implements Tempus::Stepper< Scalar >.

Definition at line 137 of file Tempus_StepperDIRK_decl.hpp.

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

Implements Tempus::Stepper< Scalar >.

Definition at line 136 of file Tempus_StepperDIRK_decl.hpp.

template<class Scalar >
void Tempus::StepperDIRK< 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 159 of file Tempus_StepperDIRK_impl.hpp.

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

Set Observer.

Implements Tempus::Stepper< Scalar >.

Definition at line 86 of file Tempus_StepperDIRK_impl.hpp.

template<class Scalar >
virtual void Tempus::StepperDIRK< Scalar >::setResetInitialGuess ( bool  reset_guess)
inlinevirtual

Set parameter so that the initial guess is reset at the beginning of each timestep.

Definition at line 110 of file Tempus_StepperDIRK_decl.hpp.

template<class Scalar >
void Tempus::StepperDIRK< Scalar >::setup ( const Teuchos::RCP< const Thyra::ModelEvaluator< Scalar > > &  wrapperModel,
const Teuchos::RCP< StepperRKObserver< Scalar > > &  obs,
const Teuchos::RCP< Thyra::NonlinearSolverBase< Scalar > > &  solver,
bool  useFSAL,
std::string  ICConsistency,
bool  ICConsistencyCheck,
bool  useEmbedded,
bool  zeroInitialGuess 
)
protectedvirtual

Setup for constructor.

Definition at line 39 of file Tempus_StepperDIRK_impl.hpp.

template<class Scalar >
void Tempus::StepperDIRK< Scalar >::setupDefault ( )
protectedvirtual

Default setup for constructor.

Definition at line 26 of file Tempus_StepperDIRK_impl.hpp.

template<class Scalar >
virtual void Tempus::StepperDIRK< Scalar >::setUseEmbedded ( bool  a)
inlinevirtual

Use embedded if avialable.

Definition at line 167 of file Tempus_StepperDIRK_decl.hpp.

template<class Scalar >
void Tempus::StepperDIRK< 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 175 of file Tempus_StepperDIRK_impl.hpp.

Member Data Documentation

template<class Scalar >
Teuchos::RCP<Thyra::VectorBase<Scalar> > Tempus::StepperDIRK< Scalar >::abs_u
protected

Definition at line 203 of file Tempus_StepperDIRK_decl.hpp.

template<class Scalar >
Teuchos::RCP<Thyra::VectorBase<Scalar> > Tempus::StepperDIRK< Scalar >::abs_u0
protected

Definition at line 202 of file Tempus_StepperDIRK_decl.hpp.

template<class Scalar >
Teuchos::RCP<Thyra::VectorBase<Scalar> > Tempus::StepperDIRK< Scalar >::ee_
protected

Definition at line 201 of file Tempus_StepperDIRK_decl.hpp.

template<class Scalar >
bool Tempus::StepperDIRK< Scalar >::resetGuess_ = true
protected

Definition at line 206 of file Tempus_StepperDIRK_decl.hpp.

template<class Scalar >
Teuchos::RCP<Thyra::VectorBase<Scalar> > Tempus::StepperDIRK< Scalar >::sc
protected

Definition at line 204 of file Tempus_StepperDIRK_decl.hpp.

template<class Scalar >
Teuchos::RCP<Thyra::VectorBase<Scalar> > Tempus::StepperDIRK< Scalar >::stageX_
protected

Definition at line 194 of file Tempus_StepperDIRK_decl.hpp.

template<class Scalar >
std::vector<Teuchos::RCP<Thyra::VectorBase<Scalar> > > Tempus::StepperDIRK< Scalar >::stageXDot_
protected

Definition at line 193 of file Tempus_StepperDIRK_decl.hpp.

template<class Scalar >
Teuchos::RCP<StepperRKObserverComposite<Scalar> > Tempus::StepperDIRK< Scalar >::stepperObserver_
protected

Definition at line 197 of file Tempus_StepperDIRK_decl.hpp.

template<class Scalar >
Teuchos::RCP<RKButcherTableau<Scalar> > Tempus::StepperDIRK< Scalar >::tableau_
protected

Definition at line 191 of file Tempus_StepperDIRK_decl.hpp.

template<class Scalar >
bool Tempus::StepperDIRK< Scalar >::useEmbedded_
protected

Definition at line 200 of file Tempus_StepperDIRK_decl.hpp.

template<class Scalar >
Teuchos::RCP<Thyra::VectorBase<Scalar> > Tempus::StepperDIRK< Scalar >::xTilde_
protected

Definition at line 195 of file Tempus_StepperDIRK_decl.hpp.


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