Tempus_StepperNewmarkExplicitAForm_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_StepperNewmarkExplicitAForm_decl_hpp
#define Tempus_StepperNewmarkExplicitAForm_decl_hpp

#include "Tempus_config.hpp"
#include "Tempus_Stepper.hpp"

namespace Tempus {


/** \brief Newmark Explicit time stepper.  This is the specific case of the
 *  more general Newmark time stepper in the case this stepper is explicit (beta = 0).
 *  Newmark Explicit is hence an explicit time stepper (i.e., no solver used).
 */
template<class Scalar>
class StepperNewmarkExplicitAForm : virtual public Tempus::Stepper<Scalar>
{
public:

  /// Constructor
  StepperNewmarkExplicitAForm(
    const Teuchos::RCP<const Thyra::ModelEvaluator<Scalar> >& appModel,
    Teuchos::RCP<Teuchos::ParameterList> pList = Teuchos::null);

  /// \name Basic 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 void setSolver(std::string solverName);
    virtual void setSolver(
      Teuchos::RCP<Teuchos::ParameterList> solverPL=Teuchos::null);
    virtual void setSolver(
        Teuchos::RCP<Thyra::NonlinearSolverBase<Scalar> > solver);
    virtual Teuchos::RCP<Thyra::NonlinearSolverBase<Scalar> > getSolver() const
      { return Teuchos::null; }

    virtual void setObserver(
      Teuchos::RCP<StepperObserver<Scalar> > obs = Teuchos::null){}

    /// Initialize during construction and after changing input parameters.
    virtual void initialize();

    /// Take the specified timestep, dt, and return true if successful.
    virtual void takeStep(
      const Teuchos::RCP<SolutionHistory<Scalar> >& solutionHistory);

    /// Pass initial guess to Newton solver (only relevant for implicit solvers)
    virtual void setInitialGuess(Teuchos::RCP<const Thyra::VectorBase<Scalar> > initial_guess)
       {initial_guess_ = initial_guess;}

    virtual std::string getStepperType() const
     { return stepperPL_->get<std::string>("Stepper Type"); }

    /// Get a default (initial) StepperState
    virtual Teuchos::RCP<Tempus::StepperState<Scalar> > getDefaultStepperState();
    virtual Scalar getOrder() const {
      if (gamma_ == 0.5) return 2.0;
      else return 1.0;
    }
    virtual Scalar getOrderMin() const {return 1.0;}
    virtual Scalar getOrderMax() const {return 2.0;}
    virtual Scalar getInitTimeStep(
        const Teuchos::RCP<SolutionHistory<Scalar> >& solutionHistory) const
      {return std::numeric_limits<Scalar>::max();}

    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();}
  //@}

  /// \name 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;
  //@}

  /// \name Overridden from Teuchos::Describable
  //@{
    virtual std::string description() const;
    virtual void describe(Teuchos::FancyOStream        & out,
                          const Teuchos::EVerbosityLevel verbLevel) const;
  //@}

    void predictVelocity(Thyra::VectorBase<Scalar>& vPred,
                             const Thyra::VectorBase<Scalar>& v,
                             const Thyra::VectorBase<Scalar>& a,
                             const Scalar dt) const;

    void predictDisplacement(Thyra::VectorBase<Scalar>& dPred,
                               const Thyra::VectorBase<Scalar>& d,
                               const Thyra::VectorBase<Scalar>& v,
                               const Thyra::VectorBase<Scalar>& a,
                               const Scalar dt) const;

    void correctVelocity(Thyra::VectorBase<Scalar>& v,
                             const Thyra::VectorBase<Scalar>& vPred,
                             const Thyra::VectorBase<Scalar>& a,
                             const Scalar dt) const;


private:

  /// Default Constructor -- not allowed

private:

  /// Default Constructor -- not allowed
  StepperNewmarkExplicitAForm();

protected:

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

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

  Scalar gamma_;

  Teuchos::RCP<Teuchos::FancyOStream> out_;

  Teuchos::RCP<const Thyra::VectorBase<Scalar> >      initial_guess_;


};
} // namespace Tempus

#endif // Tempus_StepperNewmarkExplicitAForm_decl_hpp