Tensor2_pointer.hpp

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/* A version for pointers. */
 
#pragma once
 
namespace FTensor {
 
template <class T, int Tensor_Dim0, int Tensor_Dim1>
class Tensor2<T *, Tensor_Dim0, Tensor_Dim1> {
 
protected:
 
  mutable T *restrict data[Tensor_Dim0][Tensor_Dim1];
  const int inc;
  
public:
  /* Initializations for varying numbers of elements. */
 
  Tensor2(T *d00, T *d01, T *d10, T *d11, const int i) : inc(i) {
    Tensor2_constructor<T *restrict, Tensor_Dim0, Tensor_Dim1, column_major>(
        data, d00, d01, d10, d11);
  }
  Tensor2(T *d00, T *d01, T *d10, T *d11, T *d20, T *d21, const int i)
      : inc(i) {
    Tensor2_constructor<T *restrict, Tensor_Dim0, Tensor_Dim1, column_major>(
        data, d00, d01, d10, d11, d20, d21);
  }
  Tensor2(T *d00, T *d01, T *d02, T *d10, T *d11, T *d12, T *d20, T *d21,
          T *d22, const int i)
      : inc(i) {
    Tensor2_constructor<T *restrict, Tensor_Dim0, Tensor_Dim1, column_major>(
        data, d00, d01, d02, d10, d11, d12, d20, d21, d22);
  }
  Tensor2(T *d00, T *d01, T *d02, T *d03, T *d10, T *d11, T *d12, T *d13,
          T *d20, T *d21, T *d22, T *d23, T *d30, T *d31, T *d32, T *d33,
          const int i)
      : inc(i) {
    Tensor2_constructor<T *restrict, Tensor_Dim0, Tensor_Dim1, column_major>(
        data, d00, d01, d02, d03, d10, d11, d12, d13, d20, d21, d22, d23, d30,
        d31, d32, d33);
  }
 
  /* Initializations for varying numbers of elements. */
  template <class... U> Tensor2(U *...d) : data{d...}, inc(1) {}
 
  template <class U>
  Tensor2(std::array<U *, Tensor_Dim0 * Tensor_Dim1> &a, const int i = 1)
      : inc(i) {
    int k = 0;
    for (int i = 0; i != Tensor_Dim0; ++i) {
      for (int j = 0; j != Tensor_Dim1; ++j, ++k) {
        data[i][j] = a[k];
      }
    }
  }
 
  Tensor2() {}
 
  Tensor2(const int i = 1) : inc(i) {}
 
  /* There are two operator(int,int)'s, one for non-consts that lets you
     change the value, and one for consts that doesn't. */
 
  T &operator()(const int N1, const int N2) {
#ifdef FTENSOR_DEBUG
    if (N1 >= Tensor_Dim0 || N1 < 0 || N2 >= Tensor_Dim1 || N2 < 0) {
      std::stringstream s;
      s << "Bad index in Tensor2<T*," << Tensor_Dim0 << "," << Tensor_Dim1
        << ">.operator(" << N1 << "," << N2 << ")" << std::endl;
      throw std::out_of_range(s.str());
    }
#endif
    return *data[N1][N2];
  }
 
  T operator()(const int N1, const int N2) const {
#ifdef FTENSOR_DEBUG
    if (N1 >= Tensor_Dim0 || N1 < 0 || N2 >= Tensor_Dim1 || N2 < 0) {
      std::stringstream s;
      s << "Bad index in Tensor2<T*," << Tensor_Dim0 << "," << Tensor_Dim1
        << ">.operator(" << N1 << "," << N2 << ") const" << std::endl;
      throw std::out_of_range(s.str());
    }
#endif
    return *data[N1][N2];
  }
 
  T *ptr(const int N1, const int N2) const {
#ifdef FTENSOR_DEBUG
    if (N1 >= Tensor_Dim0 || N1 < 0 || N2 >= Tensor_Dim1 || N2 < 0) {
      std::stringstream s;
      s << "Bad index in Tensor2<T*," << Tensor_Dim0 << "," << Tensor_Dim1
        << ">.ptr(" << N1 << "," << N2 << ")" << std::endl;
      throw std::out_of_range(s.str());
    }
#endif
    return data[N1][N2];
  }
 
  /* These operator()'s are the first part in constructing template
     expressions.  They can be used to slice off lower dimensional
     parts. They are not entirely safe, since you can accidentaly use a
     higher dimension than what is really allowed (like Dim=5). */
 
  template <char i, char j, int Dim0, int Dim1>
  Tensor2_Expr<Tensor2<T *, Tensor_Dim0, Tensor_Dim1>, T, Dim0, Dim1, i, j>
  operator()(const Index<i, Dim0>, const Index<j, Dim1> index2) {
    return Tensor2_Expr<Tensor2<T *, Tensor_Dim0, Tensor_Dim1>, T, Dim0, Dim1,
                        i, j>(*this);
  }
 
  template <char i, char j, int Dim0, int Dim1>
  Tensor2_Expr<const Tensor2<T *, Tensor_Dim0, Tensor_Dim1>, T, Dim0, Dim1, i,
               j>
  operator()(const Index<i, Dim0>, const Index<j, Dim1> index2) const {
    return Tensor2_Expr<const Tensor2<T *, Tensor_Dim0, Tensor_Dim1>, T, Dim0,
                        Dim1, i, j>(*this);
  }
 
  /* This is for expressions where a number is used for one slot, and
     an index for another, yielding a Tensor1_Expr.  The non-const
     versions don't actually create a Tensor2_number_rhs_[01] object.
     They create a Tensor1_Expr directly, which provides the
     appropriate indexing operators.  The const versions do create a
     Tensor2_number_[01]. */
 
  template <char i, int Dim, int N>
  Tensor1_Expr<
      Tensor2_number_rhs_1<Tensor2<T *, Tensor_Dim0, Tensor_Dim1>, T, N>, T,
      Dim, i>
  operator()(const Index<i, Dim>, const Number<N>) {
    using TensorExpr =
        Tensor2_number_rhs_1<Tensor2<T *, Tensor_Dim0, Tensor_Dim1>, T, N>;
    return Tensor1_Expr<TensorExpr, T, Dim, i>(*this);
  }
 
  template <char i, int Dim, int N>
  Tensor1_Expr<
      Tensor2_number_rhs_0<Tensor2<T *, Tensor_Dim0, Tensor_Dim1>, T, N>, T,
      Dim, i>
  operator()(const Number<N>, const Index<i, Dim>) {
    using TensorExpr =
        Tensor2_number_rhs_0<Tensor2<T *, Tensor_Dim0, Tensor_Dim1>, T, N>;
    return Tensor1_Expr<TensorExpr, T, Dim, i>(*this);
  }
 
  template <char i, int Dim, int N>
  Tensor1_Expr<const Tensor2_number_1<
                   const Tensor2<T *, Tensor_Dim0, Tensor_Dim1>, T, N>,
               T, Dim, i>
  operator()(const Index<i, Dim>, const Number<N>) const {
    using TensorExpr =
        Tensor2_number_1<const Tensor2<T *, Tensor_Dim0, Tensor_Dim1>, T, N>;
    return Tensor1_Expr<TensorExpr, T, Dim, i>(TensorExpr(*this));
  }
 
  template <char i, int Dim, int N>
  Tensor1_Expr<const Tensor2_number_0<
                   const Tensor2<T *, Tensor_Dim0, Tensor_Dim1>, T, N>,
               T, Dim, i>
  operator()(const Number<N>, const Index<i, Dim>) const {
    using TensorExpr =
        Tensor2_number_0<const Tensor2<T *, Tensor_Dim0, Tensor_Dim1>, T, N>;
    return Tensor1_Expr<TensorExpr, T, Dim, i>(TensorExpr(*this));
  }
 
  /* The ++ operator increments the pointer, not the number that the
     pointer points to.  This allows iterating over a grid. */
 
  const Tensor2 &operator++() const {
    for (int i = 0; i < Tensor_Dim0; ++i)
      for (int j = 0; j < Tensor_Dim1; ++j)
        data[i][j] += inc;
    return *this;
  }
 
  /* These two operator()'s return the Tensor2 with internal
     contractions, yielding a T.  I have to specify one for both
     const and non-const because otherwise they compiler will use the
     operator() which gives a Tensor2_Expr<>. */
 
  template <char i, int Dim>
  T operator()(const Index<i, Dim>, const Index<i, Dim> index2) {
    return internal_contract(Number<Dim>());
  }
 
  template <char i, int Dim>
  T operator()(const Index<i, Dim>, const Index<i, Dim> index2) const {
    return internal_contract(Number<Dim>());
  }
 
private:
  template <int N> T internal_contract(Number<N>) const {
    return *data[N - 1][N - 1] + internal_contract(Number<N - 1>());
  }
 
  T internal_contract(Number<1>) const { return *data[0][0]; }
 
private:
  /**
   * @brief Preventing casting on derived class
   *
   * That can be source of errors
   *
   */
  template <int I>
  Tensor2(const Tensor2<PackPtr<T *, I>, Tensor_Dim0, Tensor_Dim1> &) = delete;
};
 
template <class T, int Tensor_Dim0, int Tensor_Dim1, int I>
class Tensor2<PackPtr<T *, I>, Tensor_Dim0, Tensor_Dim1>
    : public Tensor2<T *, Tensor_Dim0, Tensor_Dim1> {
 
public:
  /* Initializations for varying numbers of elements. */
  template <class... U>
  Tensor2(U *...d) : Tensor2<T *, Tensor_Dim0, Tensor_Dim1>(d...) {}
 
  Tensor2() : Tensor2<T, Tensor_Dim0, Tensor_Dim1>() {}
 
  template <class U>
  Tensor2(std::array<U *, Tensor_Dim0 * Tensor_Dim1> &a)
      : Tensor2<T *, Tensor_Dim0, Tensor_Dim1>(a) {}
 
  /* The ++ operator increments the pointer, not the number that the
     pointer points to.  This allows iterating over a grid. */
 
  const Tensor2 &operator++() const {
    for (int i = 0; i < Tensor_Dim0; ++i)
      for (int j = 0; j < Tensor_Dim1; ++j)
        Tensor2<T *, Tensor_Dim0, Tensor_Dim1>::data[i][j] += I;
    return *this;
  }
};
 
} // namespace FTensor