Sacado_Fad_SFad.hpp

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// @HEADER
// *****************************************************************************
//                           Sacado Package
//
// Copyright 2006 NTESS and the Sacado contributors.
// SPDX-License-Identifier: LGPL-2.1-or-later
//
// ***********************************************************************
//
// 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_FAD_SFAD_HPP
#define SACADO_FAD_SFAD_HPP

#include "Sacado_ConfigDefs.h"

#ifdef SACADO_NEW_FAD_DESIGN_IS_DEFAULT

#include "Sacado_Fad_Exp_SFad.hpp"

namespace Sacado {
  namespace Fad {
    template <typename T, int Num>
    using SFad = Exp::GeneralFad< Exp::StaticFixedStorage<T,Num> >;
  }
}

#else

#include "Sacado_Fad_SFadTraits.hpp"
#include "Sacado_Fad_Expression.hpp"
#include "Sacado_StaticArrayTraits.hpp"

namespace Sacado {

  namespace Fad {

#ifndef SACADO_FAD_DERIV_LOOP
#if defined(SACADO_VIEW_CUDA_HIERARCHICAL_DFAD) && !defined(SACADO_DISABLE_CUDA_IN_KOKKOS) && defined(__CUDA_ARCH__)
#define SACADO_FAD_DERIV_LOOP(I,SZ) for (int I=threadIdx.x; I<SZ; I+=blockDim.x)
#else
#define SACADO_FAD_DERIV_LOOP(I,SZ) for (int I=0; I<SZ; ++I)
#endif
#endif

#ifndef SACADO_FAD_THREAD_SINGLE
#if (defined(SACADO_VIEW_CUDA_HIERARCHICAL) || defined(SACADO_VIEW_CUDA_HIERARCHICAL_DFAD)) && !defined(SACADO_DISABLE_CUDA_IN_KOKKOS) && defined(__CUDA_ARCH__)
#define SACADO_FAD_THREAD_SINGLE if (threadIdx.x == 0)
#else
#define SACADO_FAD_THREAD_SINGLE /* */
#endif
#endif

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

    // Forward declaration
    template <typename T, int Num> class SFad;

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

    public:

      typedef typename RemoveConst<T>::type value_type;

      typedef typename ScalarType<value_type>::type scalar_type;

      typedef SFad<value_type,Num> base_expr_type;


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


      template <typename S>
      SACADO_INLINE_FUNCTION
      Expr(const S & x, SACADO_ENABLE_VALUE_CTOR_DECL) :
        val_(x) {
        ss_array<T>::zero(dx_, Num);
      }


      SACADO_INLINE_FUNCTION
      Expr(const int sz, const T & x, const DerivInit zero_out = InitDerivArray)  : val_(x) {
#if defined(SACADO_DEBUG) && !defined(__CUDA_ARCH__ )
        if (sz != Num)
          throw "SFad::SFad() Error:  Supplied derivative dimension does not match compile time length.";
#endif
        if (zero_out == InitDerivArray)
          ss_array<T>::zero(dx_, Num);
      }


      SACADO_INLINE_FUNCTION
      Expr(const int sz, const int i, const T & x) :
        val_(x) {
#if defined(SACADO_DEBUG) && !defined(__CUDA_ARCH__ )
        if (sz != Num)
          throw "SFad::SFad() Error:  Supplied derivative dimension does not match compile time length.";
        if (i >= Num)
          throw "SFad::SFad() Error:  Invalid derivative index.";
#endif

        ss_array<T>::zero(dx_, Num);
        dx_[i]=1.;
      }

      SACADO_INLINE_FUNCTION
      Expr(const Expr& x) :
        val_(x.val()) {
        for (int i=0; i<Num; i++)
          dx_[i] = x.dx_[i];
      }

      template <typename S>
      SACADO_INLINE_FUNCTION
      Expr(const Expr<S>& x, SACADO_ENABLE_EXPR_CTOR_DECL) {
#if defined(SACADO_DEBUG) && !defined(__CUDA_ARCH__ )
        if (x.size() != Num)
          throw "SFad::SFad() Error:  Attempt to assign with incompatible sizes";
#endif

        for(int i=0; i<Num; ++i)
          dx_[i] = x.fastAccessDx(i);

        this->val() = x.val();
      }

      SACADO_INLINE_FUNCTION
      ~Expr() {}


      SACADO_INLINE_FUNCTION
      void diff(const int ith, const int n) {
#if defined(SACADO_DEBUG) && !defined(__CUDA_ARCH__ )
        if (n != Num)
          throw "SFad::diff() Error:  Supplied derivative dimension does not match compile time length.";
#endif

        ss_array<T>::zero(dx_, Num);
        dx_[ith] = T(1.);
      }


      SACADO_INLINE_FUNCTION
      void resize(int sz) {
#if defined(SACADO_DEBUG) && !defined(__CUDA_ARCH__ )
        if (sz != Num)
          throw "SFad::resize() Error:  Cannot resize fixed derivative array dimension";
#endif
      }


      SACADO_INLINE_FUNCTION
      void expand(int sz) { resize(sz); }

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

      SACADO_INLINE_FUNCTION
      void setUpdateValue(bool update_val) {  }

      SACADO_INLINE_FUNCTION
      bool updateValue() const { return true; }

      SACADO_INLINE_FUNCTION
      void cache() const {}

      template <typename S>
      SACADO_INLINE_FUNCTION
      SACADO_ENABLE_EXPR_FUNC(bool) isEqualTo(const Expr<S>& x) const {
        typedef IsEqual<value_type> IE;
        if (x.size() != this->size()) return false;
        bool eq = IE::eval(x.val(), this->val());
        for (int i=0; i<this->size(); i++)
          eq = eq && IE::eval(x.dx(i), this->dx(i));
        return eq;
      }



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

      SACADO_INLINE_FUNCTION
      T& val() { return val_;}



      SACADO_INLINE_FUNCTION
      int size() const { return Num;}

      SACADO_INLINE_FUNCTION
      int availableSize() const { return Num; }

      SACADO_INLINE_FUNCTION
      bool hasFastAccess() const { return true; }

      SACADO_INLINE_FUNCTION
      bool isPassive() const { return false; }

      SACADO_INLINE_FUNCTION
      void setIsConstant(bool is_const) {}

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

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

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

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



      template <typename S>
      SACADO_INLINE_FUNCTION
      SACADO_ENABLE_VALUE_FUNC(Expr&) operator=(const S& v) {
        val_ = v;
        ss_array<T>::zero(dx_, Num);
        return *this;
      }

      SACADO_INLINE_FUNCTION
      Expr& operator=(const Expr& x) {
        if (this != &x) {
          // Copy value
          val_ = x.val_;

          // Copy dx_
          for (int i=0; i<Num; i++)
            dx_[i] = x.dx_[i];
        }
        return *this;
      }

      template <typename S>
      SACADO_INLINE_FUNCTION
      SACADO_ENABLE_EXPR_FUNC(Expr&) operator=(const Expr<S>& x) {
#if defined(SACADO_DEBUG) && !defined(__CUDA_ARCH__ )
        if (x.size() != Num)
          throw "SFad::operator=() Error:  Attempt to assign with incompatible sizes";
#endif

        for(int i=0; i<Num; ++i)
          dx_[i] = x.fastAccessDx(i);

        val_ = x.val();

        return *this;
      }



      template <typename S>
      SACADO_INLINE_FUNCTION
      SACADO_ENABLE_VALUE_FUNC(Expr&) operator += (const S& v) {
        this->val() += v;
        return *this;
      }

      template <typename S>
      SACADO_INLINE_FUNCTION
      SACADO_ENABLE_VALUE_FUNC(Expr&) operator -= (const S& v) {
        this->val() -= v;
        return *this;
      }

      template <typename S>
      SACADO_INLINE_FUNCTION
      SACADO_ENABLE_VALUE_FUNC(Expr&) operator *= (const S& v) {
        this->val() *= v;
        for (int i=0; i<Num; ++i)
          dx_[i] *= v;
        return *this;
      }

      template <typename S>
      SACADO_INLINE_FUNCTION
      SACADO_ENABLE_VALUE_FUNC(Expr&) operator /= (const S& v) {
        this->val() /= v;
        for (int i=0; i<Num; ++i)
          dx_[i] /= v;
        return *this;
      }

      template <typename S>
      SACADO_INLINE_FUNCTION
      SACADO_ENABLE_EXPR_FUNC(Expr&) operator += (const Expr<S>& x) {
#if defined(SACADO_DEBUG) && !defined(__CUDA_ARCH__ )
        if (x.size() != Num)
          throw "SFad::operator+=() Error:  Attempt to assign with incompatible sizes";
#endif

        for (int i=0; i<Num; ++i)
          dx_[i] += x.fastAccessDx(i);

        val_ += x.val();

        return *this;
      }

      template <typename S>
      SACADO_INLINE_FUNCTION
      SACADO_ENABLE_EXPR_FUNC(Expr&) operator -= (const Expr<S>& x) {
#if defined(SACADO_DEBUG) && !defined(__CUDA_ARCH__ )
        if (x.size() != Num)
          throw "SFad::operator-=() Error:  Attempt to assign with incompatible sizes";
#endif

        for(int i=0; i<Num; ++i)
          dx_[i] -= x.fastAccessDx(i);

        val_ -= x.val();

        return *this;
      }

      template <typename S>
      SACADO_INLINE_FUNCTION
      SACADO_ENABLE_EXPR_FUNC(Expr&) operator *= (const Expr<S>& x) {
        T xval = x.val();

#if defined(SACADO_DEBUG) && !defined(__CUDA_ARCH__ )
        if (x.size() != Num)
          throw "SFad::operator*=() Error:  Attempt to assign with incompatible sizes";
#endif

        for(int i=0; i<Num; ++i)
          dx_[i] = val_ * x.fastAccessDx(i) + dx_[i] * xval;

        val_ *= xval;

        return *this;
      }

      template <typename S>
      SACADO_INLINE_FUNCTION
      SACADO_ENABLE_EXPR_FUNC(Expr&) operator /= (const Expr<S>& x) {
        T xval = x.val();

#if defined(SACADO_DEBUG) && !defined(__CUDA_ARCH__ )
        if (x.size() != Num)
          throw "SFad::operator/=() Error:  Attempt to assign with incompatible sizes";
#endif

        for(int i=0; i<Num; ++i)
          dx_[i] = ( dx_[i]*xval - val_*x.fastAccessDx(i) )/ (xval*xval);

        val_ /= xval;

        return *this;
      }


    protected:

      T dx_[Num];

      T val_;

    }; // class Expr<SFadExprTag>

  } // namespace Fad

} // namespace Sacado

#define FAD_NS Fad
#include "Sacado_Fad_SFad_tmpl.hpp"
#undef FAD_NS

#include "Sacado_Fad_Ops.hpp"

#endif // SACADO_NEW_FAD_DESIGN_IS_DEFAULT

#include "Sacado_Fad_ViewFad.hpp"

#endif // SACADO_FAD_SFAD_HPP