Ddg_carat_Ddg.hpp

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/* This file has all of the declarations for expressions like
   Ddg^Ddg, yielding a Ddg. */
 
#pragma once
 
namespace FTensor
{
  /* A(i,j,k,l)*B(j,l,m,n) */
 
  template <class A, class B, class T, class U, int Dim, int Dim23, char i,
            char j, char k, char l, char m, char n>
  class Ddg_carat_Ddg_13
  {
    Ddg_Expr<A, T, Dim, Dim, i, j, k, l> iterA;
    Ddg_Expr<B, U, Dim, Dim23, j, l, m, n> iterB;
 
    template <int Current_Dim0, int Current_Dim1>
    typename promote<T, U>::V
    eval(const int N1, const int N2, const int N3, const int N4,
         const Number<Current_Dim0> &, const Number<Current_Dim1> &) const
    {
      return iterA(Current_Dim0 - 1, N1, Current_Dim1 - 1, N2)
               * iterB(Current_Dim0 - 1, Current_Dim1 - 1, N3, N4)
             + eval(N1, N2, N3, N4, Number<Current_Dim0 - 1>(),
                    Number<Current_Dim1>());
    }
    template <int Current_Dim1>
    typename promote<T, U>::V
    eval(const int N1, const int N2, const int N3, const int N4,
         const Number<1> &, const Number<Current_Dim1> &) const
    {
      return iterA(0, N1, Current_Dim1 - 1, N2)
               * iterB(0, Current_Dim1 - 1, N3, N4)
             + eval(N1, N2, N3, N4, Number<Dim>(), Number<Current_Dim1 - 1>());
    }
    typename promote<T, U>::V
    eval(const int N1, const int N2, const int N3, const int N4,
         const Number<1> &, const Number<1> &) const
    {
      return iterA(0, N1, 0, N2) * iterB(0, 0, N3, N4);
    }
 
  public:
    Ddg_carat_Ddg_13(const Ddg_Expr<A, T, Dim, Dim, i, j, k, l> &a,
                     const Ddg_Expr<B, U, Dim, Dim23, j, l, m, n> &b)
        : iterA(a), iterB(b)
    {}
    typename promote<T, U>::V
    operator()(const int N1, const int N2, const int N3, const int N4) const
    {
      return eval(N1, N2, N3, N4, Number<Dim>(), Number<Dim>());
    }
  };
 
  template <class A, class B, class T, class U, int Dim, int Dim23, char i,
            char j, char k, char l, char m, char n>
  Ddg_Expr<Ddg_carat_Ddg_13<A, B, T, U, Dim, Dim23, i, j, k, l, m, n>,
           typename promote<T, U>::V, Dim, Dim23, i, k, m, n>
  operator^(const Ddg_Expr<A, T, Dim, Dim, i, j, k, l> &a,
            const Ddg_Expr<B, U, Dim, Dim23, j, l, m, n> &b)
  {
    using TensorExpr
      = Ddg_carat_Ddg_13<A, B, T, U, Dim, Dim23, i, j, k, l, m, n>;
    return Ddg_Expr<TensorExpr, typename promote<T, U>::V, Dim, Dim23, i, k, m,
                    n>(TensorExpr(a, b));
  }
}