// $Id$ 
// $Source$ 
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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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#ifndef SACADO_ELRFAD_SLFAD_HPP
#define SACADO_ELRFAD_SLFAD_HPP

#include "Sacado_ELRFad_GeneralFadExpr.hpp"
#include "Sacado_ELRFad_SLFadTraits.hpp"
#include "Sacado_Fad_StaticStorage.hpp"
#include "Sacado_dummy_arg.hpp"

namespace Sacado {

  namespace ELRFad {

    /*! 
     * \brief Forward-mode AD class using static memory allocation
     * with long arrays and expression templates with expression-level
     * reverse mode.
     */
    /*!
     * This is the user-level class for forward mode AD with static
     * memory allocation, and is appropriate for whenever the number
     * of derivative components is known at compile time.  The largest size
     * of the derivative array is fixed by the template parameter \c Num
     * while the actual size used is set by the \c sz argument to the 
     * constructor or the \c n argument to diff().  The user
     * interface is provided by Sacado::Fad::GeneralFad.
     */
    template <typename ValueT, int Num>
    class SLFad : 
      public Expr< GeneralFad<ValueT,Fad::StaticStorage<ValueT,Num> > > {

    public:

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

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

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

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

      //! Constructor with supplied value \c x
      /*!
       * Initializes value to \c x and derivative array is empty
       */
      SLFad(const ValueT& x) : 
	Expr< GeneralFad< ValueT,Fad::StaticStorage<ValueT,Num> > >(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.
       */
      SLFad(const typename dummy<ValueT,ScalarT>::type& x) : 
	Expr< GeneralFad< ValueT,Fad::StaticStorage<ValueT,Num> > >(ValueT(x)) {}

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

      //! Copy constructor
      SLFad(const SLFad& x) : 
	Expr< GeneralFad< ValueT,Fad::StaticStorage<ValueT,Num> > >(x) {}

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

      //@}

      //! Destructor
      ~SLFad() {}

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

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

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

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

    }; // class SLFad<ValueT,Num>

  } // namespace ELRFad

} // namespace Sacado

#endif // SACADO_ELRFAD_SLFAD_HPP
