Sacado_ELRFad_SFad.hpp

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// $Id: Sacado_ELRFad_SFad.hpp,v 1.2 2007/11/14 00:18:18 etphipp Exp $ 
// $Source: /space/CVS/Trilinos/packages/sacado/src/Sacado_ELRFad_SFad.hpp,v $ 
// @HEADER
// ***********************************************************************
// 
//                           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
// published by the Free Software Foundation; either version 2.1 of the
// License, or (at your option) any later version.
//  
// This library is distributed in the hope that it will be useful, but
// WITHOUT ANY WARRANTY; without even the implied warranty of
// 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
// License along with this library; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
// USA
// Questions? Contact David M. Gay (dmgay@sandia.gov) or Eric T. Phipps
// (etphipp@sandia.gov).
// 
// ***********************************************************************
//
// The forward-mode AD classes in Sacado are a derivative work of the
// expression template classes in the Fad package by Nicolas Di Cesare.  
// The following banner is included in the original Fad source code:
//
// ************ DO NOT REMOVE THIS BANNER ****************
//
//  Nicolas Di Cesare <Nicolas.Dicesare@ann.jussieu.fr>
//  http://www.ann.jussieu.fr/~dicesare
//
//            CEMRACS 98 : C++ courses, 
//         templates : new C++ techniques 
//            for scientific computing 
// 
//********************************************************
//
//  A short implementation ( not all operators and 
//  functions are overloaded ) of 1st order Automatic
//  Differentiation in forward mode (FAD) using
//  EXPRESSION TEMPLATES.
//
//********************************************************
// @HEADER

#ifndef SACADO_ELRFAD_SFAD_HPP
#define SACADO_ELRFAD_SFAD_HPP

#include "Sacado_ELRFad_SFadTraits.hpp"
#include "Sacado_ELRFad_Expression.hpp"
#include "Sacado_StaticArrayTraits.hpp"

namespace Sacado {

  namespace ELRFad {

    template <typename T, int Num> 
    struct SFadExprTag {};

    template <typename T, int Num> 
    class Expr< SFadExprTag<T,Num> > {

    public:

      typedef T value_type;

      typedef Expr< SFadExprTag<T,Num> > base_expr_type;

      static const int num_args = 1;


      Expr() : val_( T(0.)) { ss_array<T>::zero(dx_, Num); }


      Expr(const T & x) : val_(x)  { ss_array<T>::zero(dx_, Num); }


      Expr(const int sz, const T & x);


      Expr(const int sz, const int i, const T & x);

      Expr(const Expr& x) : val_(x.val_) { 
  //ss_array<T>::copy(x.dx_, dx_, Num);
  for (int i=0; i<Num; i++)
    dx_[i] = x.dx_[i];
      }

      template <typename S> Expr(const Expr<S>& x);

      ~Expr() {}


      void diff(const int ith, const int n);


      void resize(int sz);

      void zero() { ss_array<T>::zero(dx_, Num); }



      const T& val() const { return val_;}

      T& val() { return val_;}



      int size() const { return Num;}

      bool hasFastAccess() const { return true; }

      bool isPassive() const { return false; }
      
      void setIsConstant(bool is_const) {}

      const T* dx() const { return &(dx_[0]);}

      const T& dx(int i) const { return dx_[i]; }
    
      T& fastAccessDx(int i) { return dx_[i];}

      const T& fastAccessDx(int i) const { return dx_[i];}

      void computePartials(const T& bar, T partials[]) const { 
  partials[0] = bar; 
      }

      void getTangents(int i, T dots[]) const { 
  dots[0] = this->dx_[i];
      }

      template <int Arg>
      bool isActive() const { return true; }

      template <int Arg>
      T getTangent(int i) const { return this->dx_[i]; }
    


      Expr< SFadExprTag<T,Num> >& operator=(const T& val);

      Expr< SFadExprTag<T,Num> >& 
      operator=(const Expr< SFadExprTag<T,Num> >& x);

      template <typename S> 
      Expr< SFadExprTag<T,Num> >& operator=(const Expr<S>& x); 



      Expr< SFadExprTag<T,Num> >& operator += (const T& x);

      Expr< SFadExprTag<T,Num> >& operator -= (const T& x);

      Expr< SFadExprTag<T,Num> >& operator *= (const T& x);

      Expr< SFadExprTag<T,Num> >& operator /= (const T& x);

      template <typename S> 
      Expr< SFadExprTag<T,Num> >& operator += (const Expr<S>& x);

      template <typename S> 
      Expr< SFadExprTag<T,Num> >& operator -= (const Expr<S>& x);
  
      template <typename S> 
      Expr< SFadExprTag<T,Num> >& operator *= (const Expr<S>& x);

      template <typename S> 
      Expr< SFadExprTag<T,Num> >& operator /= (const Expr<S>& x);


    protected:

      T val_;

      T dx_[Num];

      // Functor for mpl::for_each to compute the local accumulation
      // of a tangent derivative
      template <typename ExprT>
      struct LocalAccumOp {
  typedef typename ExprT::value_type value_type;
  static const int N = ExprT::num_args;
  const ExprT& x;
  mutable value_type t;
  value_type partials[N];
  int i;
  inline LocalAccumOp(const ExprT& x_) :
    x(x_) { x.computePartials(value_type(1.), partials); }
  template <typename ArgT>
  inline void operator () (ArgT arg) const {
    const int Arg = ArgT::value;
    if (x.template isActive<Arg>())
      t += partials[Arg] * x.template getTangent<Arg>(i);
  }
      };

    }; // class Expr<SFadExprTag>


    template <typename ValueT, int Num,
        typename ScalarT = typename ScalarValueType<ValueT>::type >
    class SFad : 
      public Expr< SFadExprTag<ValueT,Num > > {

    public:



      SFad() : 
  Expr< SFadExprTag< ValueT,Num > >() {}


      SFad(const ValueT & x) : 
  Expr< SFadExprTag< ValueT,Num > >(x) {}


      SFad(const ScalarT& x) : 
  Expr< SFadExprTag< ValueT,Num > >(ValueT(x)) {}


      SFad(const int sz, const ValueT & x) : 
  Expr< SFadExprTag< ValueT,Num > >(sz,x) {}


      SFad(const int sz, const int i, const ValueT & x) : 
  Expr< SFadExprTag< ValueT,Num > >(sz,i,x) {}

      SFad(const SFad& x) : 
  Expr< SFadExprTag< ValueT,Num > >(x) {}

      template <typename S> SFad(const Expr<S>& x) : 
  Expr< SFadExprTag< ValueT,Num > >(x) {}


      ~SFad() {}

      SFad& operator=(const ValueT& val) {
  Expr< SFadExprTag< ValueT,Num > >::operator=(val);
  return *this;
      }

      SFad& operator=(const ScalarT& val) {
  Expr< SFadExprTag< ValueT,Num > >::operator=(ValueT(val));
  return *this;
      }

      SFad& operator=(const SFad& x) {
  Expr< SFadExprTag< ValueT,Num > >::operator=(static_cast<const Expr< SFadExprTag< ValueT,Num > >&>(x));
  return *this;
      }

      template <typename S> SFad& operator=(const Expr<S>& x) 
      {
  Expr< SFadExprTag< ValueT,Num > >::operator=(x);
  return *this;
      }

    }; // class SFad<ValueT,Num,ScalarT>


    template <typename ValueT, int Num>
    class SFad<ValueT,Num,ValueT> : 
      public Expr< SFadExprTag<ValueT,Num >  >{

    public:



      SFad() : Expr< SFadExprTag< ValueT,Num > >() {}


      SFad(const ValueT & x) : 
  Expr< SFadExprTag< ValueT,Num > >(x) {}


      SFad(const int sz, const ValueT & x) : 
  Expr< SFadExprTag< ValueT,Num > >(sz,x) {}


      SFad(const int sz, const int i, const ValueT & x) : 
  Expr< SFadExprTag< ValueT,Num > >(sz,i,x) {}

      SFad(const SFad& x) : 
  Expr< SFadExprTag< ValueT,Num > >(x) {}

      template <typename S> SFad(const Expr<S>& x) : 
  Expr< SFadExprTag< ValueT,Num > >(x) {}


      ~SFad() {}

      SFad& operator=(const ValueT& val) {
  Expr< SFadExprTag< ValueT,Num > >::operator=(val);
  return *this;
      }

      SFad& operator=(const SFad& x) {
  Expr< SFadExprTag< ValueT,Num > >::operator=(static_cast<const Expr< SFadExprTag< ValueT,Num > >&>(x));
  return *this;
      }

      template <typename S> SFad& operator=(const Expr<S>& x) 
      {
  Expr< SFadExprTag< ValueT,Num > >::operator=(x);
  return *this;
      }

    }; // class SFad<ValueT,Num>

    template <typename T, int Num>
    struct ExprPromote< Expr< SFadExprTag<T,Num> >, T > {
      typedef Expr< SFadExprTag<T,Num> > type;
    };
    
    template <typename T, int Num>
    struct ExprPromote< T, Expr< SFadExprTag<T,Num> > > {
      typedef Expr< SFadExprTag<T,Num> > type;
    };

    template <typename T, int Num>
    std::ostream& operator << (std::ostream& os, 
             const Expr< SFadExprTag<T,Num> >& x) {
      os << x.val() << "  [";
      
      for (int i=0; i< x.size(); i++) {
  os << " " << x.dx(i);
      }

      os << " ]\n";
      return os;
    }

  } // namespace ELRFad

} // namespace Sacado

#include "Sacado_ELRFad_SFadImp.hpp"
#include "Sacado_ELRFad_Ops.hpp"

#endif // SACADO_ELRFAD_SFAD_HPP

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