// $Id$ 
// $Source$ 
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// ***********************************************************************
// 
//                           Sacado Package
//                 Copyright (2006) Sandia Corporation
// 
// Under the terms of Contract DE-AC04-94AL85000 with Sandia Corporation,
// the U.S. Government retains certain rights in this software.
// 
// This library is free software; you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as
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// This library is distributed in the hope that it will be useful, but
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
// Lesser General Public License for more details.
//  
// You should have received a copy of the GNU Lesser General Public
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// Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301
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// Questions? Contact David M. Gay (dmgay@sandia.gov) or Eric T. Phipps
// (etphipp@sandia.gov).
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#ifndef SACADO_CACHEFAD_DFAD_HPP
#define SACADO_CACHEFAD_DFAD_HPP

#include "Sacado_CacheFad_GeneralFadExpr.hpp"
#include "Sacado_CacheFad_DFadTraits.hpp"
#include "Sacado_Fad_DynamicStorage.hpp"
#include "Sacado_dummy_arg.hpp"

namespace Sacado {

  namespace CacheFad {

    /*! 
     * \brief Forward-mode AD class using dynamic memory allocation and
     * caching expression templates.
     */
    /*!
     * This is a user-level class for forward mode AD with dynamic
     * memory allocation, and is appropriate for whenever the number
     * of derivative components is not known at compile time.  The user
     * interface is provided by Sacado::CacheFad::GeneralFad.  It is similar
     * to Sacado::Fad::DFad, except it uses the caching expression templates
     * that cache the results of val() calculations for later dx() 
     * calculations.
     */
    template <typename ValueT>
    class DFad : public Expr< GeneralFad<ValueT,
					 Fad::DynamicStorage<ValueT> > > {

    public:

      //! Typename of scalar's (which may be different from ValueT)
      typedef typename ScalarType<ValueT>::type ScalarT;
      typedef typename GeneralFad<ValueT,Fad::DynamicStorage<ValueT> >::value_type value_type;
      typedef typename GeneralFad<ValueT,Fad::DynamicStorage<ValueT> >::scalar_type scalar_type;

      //! Turn DFad into a meta-function class usable with mpl::apply
      template <typename T> 
      struct apply {
	typedef DFad<T> type;
      };

      /*!
       * @name Initialization methods
       */
      //@{

      //! Default constructor.
      /*!
       * Initializes value to 0 and derivative array is empty
       */
      DFad() : 
	Expr< GeneralFad< ValueT,Fad::DynamicStorage<ValueT> > >() {}

      //! Constructor with supplied value \c x of type ValueT
      /*!
       * Initializes value to \c x and derivative array is empty
       */
      DFad(const ValueT& x) : 
	Expr< GeneralFad< ValueT,Fad::DynamicStorage<ValueT> > >(x) {}

      //! Constructor with supplied value \c x of type ScalarT
      /*!
       * Initializes value to \c ValueT(x) and derivative array is empty.
       * Creates a dummy overload when ValueT and ScalarT are the same type.
       */
      DFad(const typename dummy<ValueT,ScalarT>::type& x) : 
	Expr< GeneralFad< ValueT,Fad::DynamicStorage<ValueT> > >(ValueT(x)) {}

      //! Constructor with size \c sz and value \c x
      /*!
       * Initializes value to \c x and derivative array 0 of length \c sz
       */
      DFad(const int sz, const ValueT& x) : 
	Expr< GeneralFad< ValueT,Fad::DynamicStorage<ValueT> > >(sz,x) {}

      //! Constructor with size \c sz, index \c i, and value \c x
      /*!
       * Initializes value to \c x and derivative array of length \c sz
       * as row \c i of the identity matrix, i.e., sets derivative component
       * \c i to 1 and all other's to zero.
       */
      DFad(const int sz, const int i, const ValueT & x) : 
	Expr< GeneralFad< ValueT,Fad::DynamicStorage<ValueT> > >(sz,i,x) {}

      //! Copy constructor
      DFad(const DFad& x) : 
	Expr< GeneralFad< ValueT,Fad::DynamicStorage<ValueT> > >(x) {}

      //! Copy constructor from any Expression object
      template <typename S> DFad(const Expr<S>& x) : 
	Expr< GeneralFad< ValueT,Fad::DynamicStorage<ValueT> > >(x) {}

      //@}

      //! Destructor
      ~DFad() {}

      //! Assignment operator with constant right-hand-side
      DFad& operator=(const ValueT& v) {
	GeneralFad< ValueT,Fad::DynamicStorage<ValueT> >::operator=(v);
	return *this;
      }

      //! Assignment operator with constant right-hand-side
      /*!
       * Creates a dummy overload when ValueT and ScalarT are the same type.
       */
      DFad& operator=(const typename dummy<ValueT,ScalarT>::type& v) {
	GeneralFad< ValueT,Fad::DynamicStorage<ValueT> >::operator=(ValueT(v));
	return *this;
      }

      //! Assignment operator with DFad right-hand-side
      DFad& operator=(const DFad& x) {
	GeneralFad< ValueT,Fad::DynamicStorage<ValueT> >::operator=(static_cast<const GeneralFad< ValueT,Fad::DynamicStorage<ValueT> >&>(x));
	return *this;
      }

      //! Assignment operator with any expression right-hand-side
      template <typename S> DFad& operator=(const Expr<S>& x) 
      {
	GeneralFad< ValueT,Fad::DynamicStorage<ValueT> >::operator=(x);
	return *this;
      }
	
    }; // class DFad<ValueT>

  } // namespace CacheFad

} // namespace Sacado

#endif // SACADO_CACHEFAD_DFAD_HPP
