BelosOperator.hpp

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// @HEADER
// *****************************************************************************
//                 Belos: Block Linear Solvers Package
//
// Copyright 2004-2016 NTESS and the Belos contributors.
// SPDX-License-Identifier: BSD-3-Clause
// *****************************************************************************
// @HEADER

#ifndef BELOS_OPERATOR_HPP
#define BELOS_OPERATOR_HPP


#include "BelosConfigDefs.hpp"
#include "BelosOperatorTraits.hpp"
#include "BelosMultiVec.hpp"
#ifdef HAVE_BELOS_EXPERIMENTAL
#  include "BelosInnerSolver.hpp"
#endif // HAVE_BELOS_EXPERIMENTAL


namespace Belos {

  template <class ScalarType>
  class Operator {
  public:

    
    Operator() {};
    
    virtual ~Operator() {};
    


    virtual void 
    Apply (const MultiVec<ScalarType>& x, 
     MultiVec<ScalarType>& y, 
     ETrans trans=NOTRANS) const = 0;

    virtual bool HasApplyTranspose () const {
      return false;
    }
  };
  
  //
  // Implementation of the Belos::OperatorTraits for Belos::Operator 
  //                                               and Belos::MultiVec.
  //
  
  template<class ScalarType> 
  class OperatorTraits<ScalarType, MultiVec<ScalarType>, Operator<ScalarType> > 
  {
  public:
    static void 
    Apply (const Operator<ScalarType>& Op, 
     const MultiVec<ScalarType>& x, 
     MultiVec<ScalarType>& y,
     ETrans trans=NOTRANS)
    { 
      Op.Apply (x, y, trans); 
    }

    static bool
    HasApplyTranspose (const Operator<ScalarType>& Op)
    {
      return Op.HasApplyTranspose ();
    }
  };

#ifdef HAVE_BELOS_EXPERIMENTAL

  template<class Scalar>
  class OperatorInnerSolver : public Operator<Scalar> {
  public:
    typedef Scalar scalar_type;
    typedef MultiVec<Scalar> multivector_type;
    typedef Operator<Scalar> operator_type;
    typedef InnerSolver<scalar_type, multivector_type, operator_type> inner_solver_type;

    OperatorInnerSolver (const Teuchos::RCP<inner_solver_type>& solver) :
      solver_ (solver)
    {}
    virtual ~OperatorInnerSolver() {}

    Teuchos::RCP<inner_solver_type> getInnerSolver() const {
      return solver_;
    }

    virtual void 
    Apply (const multivector_type& X,
     multivector_type& Y,
     ETrans mode = NOTRANS) const
    {
      using Teuchos::rcpFromRef;

      TEUCHOS_TEST_FOR_EXCEPTION(mode != NOTRANS, std::invalid_argument,
       "Belos::OperatorInnerSolver only supports applying the"
       " operator itself, not its transpose or conjugate "
       "transpose.");
      solver_->solve (rcpFromRef (Y), rcpFromRef (X));
    }

    virtual bool HasApplyTranspose() const {
      return false;
    }

  private:
    OperatorInnerSolver ();

    Teuchos::RCP<inner_solver_type> solver_;
  };

  template <class Scalar>
  class InnerSolverTraits<Scalar, MultiVec<Scalar>, Operator<Scalar> > {
  public:
    typedef Scalar scalar_type;
    typedef MultiVec<scalar_type> multivector_type;
    typedef Operator<scalar_type> operator_type;
    typedef InnerSolver<scalar_type, multivector_type, operator_type> inner_solver_type;
    typedef OperatorInnerSolver<scalar_type> wrapper_type;

    static Teuchos::RCP<operator_type>
    makeInnerSolverOperator (const Teuchos::RCP<inner_solver_type>& solver)
    {
      using Teuchos::rcp;
      using Teuchos::rcp_implicit_cast;
      return rcp_implicit_cast<operator_type> (rcp (new wrapper_type (solver)));
    }

    static Teuchos::RCP<inner_solver_type>
    getInnerSolver (const Teuchos::RCP<operator_type>& op)
    {
      using Teuchos::RCP;
      using Teuchos::rcp_dynamic_cast;
      RCP<wrapper_type> wrapper = rcp_dynamic_cast<wrapper_type> (op, true);
      return wrapper->getInnerSolver();
    }
  };
#endif // HAVE_BELOS_EXPERIMENTAL
  
} // end Belos namespace

#endif

// end of file BelosOperator.hpp