Tempus_StepperTrapezoidal_decl.hpp

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//@HEADER
// *****************************************************************************
//          Tempus: Time Integration and Sensitivity Analysis Package
//
// Copyright 2017 NTESS and the Tempus contributors.
// SPDX-License-Identifier: BSD-3-Clause
// *****************************************************************************
//@HEADER

#ifndef Tempus_StepperTrapezoidal_decl_hpp
#define Tempus_StepperTrapezoidal_decl_hpp

#include "Tempus_config.hpp"
#include "Tempus_StepperImplicit.hpp"
#include "Tempus_WrapperModelEvaluator.hpp"
#include "Tempus_StepperTrapezoidalAppAction.hpp"
#include "Tempus_StepperOptimizationInterface.hpp"

namespace Tempus {

template <class Scalar>
class StepperTrapezoidal : virtual public Tempus::StepperImplicit<Scalar> {
 public:
  StepperTrapezoidal();

  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);


  virtual void setAppAction(
      Teuchos::RCP<StepperTrapezoidalAppAction<Scalar> > appAction);

  virtual Teuchos::RCP<StepperTrapezoidalAppAction<Scalar> > getAppAction()
      const
  {
    return stepperTrapAppAction_;
  }

  virtual void setInitialConditions(
      const Teuchos::RCP<SolutionHistory<Scalar> >& solutionHistory);

  virtual void takeStep(
      const Teuchos::RCP<SolutionHistory<Scalar> >& solutionHistory);

  virtual Teuchos::RCP<Tempus::StepperState<Scalar> > getDefaultStepperState();
  virtual Scalar getOrder() const { return 2.0; }
  virtual Scalar getOrderMin() const { return 2.0; }
  virtual Scalar getOrderMax() const { return 2.0; }

  virtual bool isExplicit() const { return false; }
  virtual bool isImplicit() const { return true; }
  virtual bool isExplicitImplicit() const
  {
    return isExplicit() && isImplicit();
  }
  virtual bool isOneStepMethod() const { return true; }
  virtual bool isMultiStepMethod() const { return !isOneStepMethod(); }
  virtual void setUseFSAL(bool a) { this->setUseFSALTrueOnly(a); }
  virtual OrderODE getOrderODE() const { return FIRST_ORDER_ODE; }

  virtual Scalar getAlpha(const Scalar dt) const { return Scalar(2.0) / dt; }
  virtual Scalar getBeta(const Scalar) const { return Scalar(1.0); }


  virtual void describe(Teuchos::FancyOStream& out,
                        const Teuchos::EVerbosityLevel verbLevel) const;

  virtual bool isValidSetup(Teuchos::FancyOStream& out) const;

 private:
  Teuchos::RCP<StepperTrapezoidalAppAction<Scalar> > stepperTrapAppAction_;
};

template <typename Scalar>
class StepperTrapezoidalTimeDerivative
  : virtual public Tempus::TimeDerivative<Scalar> {
 public:
  StepperTrapezoidalTimeDerivative(
      Scalar s, Teuchos::RCP<const Thyra::VectorBase<Scalar> > xOld,
      Teuchos::RCP<const Thyra::VectorBase<Scalar> > xDotOld)
  {
    initialize(s, xOld, xDotOld);
  }

  virtual ~StepperTrapezoidalTimeDerivative() {}

  virtual void compute(
      Teuchos::RCP<const Thyra::VectorBase<Scalar> > x,
      Teuchos::RCP<Thyra::VectorBase<Scalar> > xDot,
      Teuchos::RCP<Thyra::VectorBase<Scalar> > xDotDot = Teuchos::null)
  {
    xDotDot = Teuchos::null;
    // Calculate the Trapezoidal method x dot vector
    Thyra::V_StVpStV(xDot.ptr(), s_, *x, -s_, *xOld_);
    Thyra::V_VpStV(xDot.ptr(), *xDot, Scalar(-1.0), *xDotOld_);
  }

  virtual void initialize(
      Scalar s, Teuchos::RCP<const Thyra::VectorBase<Scalar> > xOld,
      Teuchos::RCP<const Thyra::VectorBase<Scalar> > xDotOld)
  {
    s_       = s;
    xOld_    = xOld;
    xDotOld_ = xDotOld;
  }

 private:
  Scalar s_;  // = 1.0/(dt/2)
  Teuchos::RCP<const Thyra::VectorBase<Scalar> > xOld_;
  Teuchos::RCP<const Thyra::VectorBase<Scalar> > xDotOld_;
};

// ------------------------------------------------------------------------
template <class Scalar>
Teuchos::RCP<StepperTrapezoidal<Scalar> > createStepperTrapezoidal(
    const Teuchos::RCP<const Thyra::ModelEvaluator<Scalar> >& model,
    Teuchos::RCP<Teuchos::ParameterList> pl);

}  // namespace Tempus

#endif  // Tempus_StepperTrapezoidal_decl_hpp