Tempus_StepperExplicit_decl.hpp

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// @HEADER
// ****************************************************************************
//                Tempus: Copyright (2017) Sandia Corporation
//
// Distributed under BSD 3-clause license (See accompanying file Copyright.txt)
// ****************************************************************************
// @HEADER

#ifndef Tempus_StepperExplicit_decl_hpp
#define Tempus_StepperExplicit_decl_hpp

// Tempus
#include "Tempus_Stepper.hpp"


template<class Scalar>
class ExplicitODEParameters
{
  public:
    /// Constructor
    ExplicitODEParameters()
      : timeStepSize_(Scalar(0.0)), stageNumber_(0)
    {}
    /// Constructor
    ExplicitODEParameters(Scalar timeStepSize, int stageNumber = 0)
      : timeStepSize_(timeStepSize), stageNumber_(stageNumber)
    {}

    Scalar                                timeStepSize_;
    int                                   stageNumber_;
};


namespace Tempus {


/** \brief Thyra Base interface for implicit time steppers.
 *
 */
template<class Scalar>
class StepperExplicit : virtual public Tempus::Stepper<Scalar>
{
public:

  /// \name Basic explicit stepper methods
  //@{
    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(){return appModel_;}

    virtual Scalar getInitTimeStep(
        const Teuchos::RCP<SolutionHistory<Scalar> >& /* solutionHistory */) const
      {return std::numeric_limits<Scalar>::max();}

    /// Set the initial conditions, make them consistent, and set needed memory.
    virtual void setInitialConditions (
      const Teuchos::RCP<SolutionHistory<Scalar> >& solutionHistory);

    virtual void setSolver(
      Teuchos::RCP<Thyra::NonlinearSolverBase<Scalar> > solver = Teuchos::null);

    virtual Teuchos::RCP<Thyra::NonlinearSolverBase<Scalar> > getSolver() const
      { return Teuchos::null; }

    /// Pass initial guess to Newton solver (only relevant for implicit solvers)
    //  thus a no-op for explicit steppers.
    virtual void setInitialGuess(
      Teuchos::RCP<const Thyra::VectorBase<Scalar> > /* initial_guess */){}

    virtual bool isExplicit()         const {return true;}
    virtual bool isImplicit()         const {return false;}
    virtual bool isExplicitImplicit() const
      {return isExplicit() and isImplicit();}
    virtual bool isOneStepMethod()    const {return true;}
    virtual bool isMultiStepMethod()  const {return !isOneStepMethod();}

    /// Set x for Stepper storage.
    virtual void setStepperX(Teuchos::RCP<Thyra::VectorBase<Scalar> > x)
      { stepperX_ = x; }
    /// Set xDot for Stepper storage.
    virtual void setStepperXDot(Teuchos::RCP<Thyra::VectorBase<Scalar> > xDot)
      { stepperXDot_ = xDot; }
    /// Set x for Stepper storage.
    virtual void setStepperXDotDot(Teuchos::RCP<Thyra::VectorBase<Scalar> > xDotDot)
      { stepperXDotDot_ = xDotDot; }

    /// Get x from SolutionState or Stepper storage.
    virtual Teuchos::RCP<Thyra::VectorBase<Scalar> > getStepperX(
      Teuchos::RCP<SolutionState<Scalar> > state);
    /// Get xDot from SolutionState or Stepper storage.
    virtual Teuchos::RCP<Thyra::VectorBase<Scalar> > getStepperXDot(
      Teuchos::RCP<SolutionState<Scalar> > state);
    /// Get xDotDot from SolutionState or Stepper storage.
    virtual Teuchos::RCP<Thyra::VectorBase<Scalar> > getStepperXDotDot(
      Teuchos::RCP<SolutionState<Scalar> > state);

    /// Evaluate xDot = f(x,t).
    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 xDotDot = f(x, xDot, t).
    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 );
  //@}

protected:

  /// Explicit ODE ModelEvaluator
  Teuchos::RCP<const Thyra::ModelEvaluator<Scalar> > appModel_;

  Thyra::ModelEvaluatorBase::InArgs<Scalar>          inArgs_;
  Thyra::ModelEvaluatorBase::OutArgs<Scalar>         outArgs_;

  Teuchos::RCP<StepperObserver<Scalar> >             stepperObserver_;

  // RCP to state or temporary storage if needed.
  Teuchos::RCP<Thyra::VectorBase<Scalar> >           stepperX_;
  Teuchos::RCP<Thyra::VectorBase<Scalar> >           stepperXDot_;
  Teuchos::RCP<Thyra::VectorBase<Scalar> >           stepperXDotDot_;
};

} // namespace Tempus
#endif // Tempus_StepperExplicit_decl_hpp