type_n_tensor.h

浏览该文件的文档.

// The libMesh Finite Element Library.
// Copyright (C) 2002-2023 Benjamin S. Kirk, John W. Peterson, Roy H. Stogner

// 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



#ifndef LIBMESH_TYPE_N_TENSOR_H
#define LIBMESH_TYPE_N_TENSOR_H

// Local includes
#include "libmesh/libmesh_common.h"
#include "libmesh/type_vector.h"
#include "libmesh/tuple_of.h"

// C++ includes
#include <cstdlib> // *must* precede <cmath> for proper std:abs() on PGI, Sun Studio CC
#include <cmath>
#include <vector>

namespace libMesh
{

template <unsigned int N, typename T>
class TypeNTensor
{
public:
  typedef tuple_of<N, unsigned int> index_type;

  // 默认构造函数
  TypeNTensor () : _coords(std::vector<T>(int_pow(LIBMESH_DIM, N))) {}

  // 复制构造函数
  TypeNTensor (const T &) : _coords(std::vector<T>(int_pow(LIBMESH_DIM, N))) {}

  // 复制构造函数
  TypeNTensor (const TypeVector<T> &) : _coords(std::vector<T>(int_pow(LIBMESH_DIM, N))) {}

  // 复制构造函数
  TypeNTensor (const TypeTensor<T> &) : _coords(std::vector<T>(int_pow(LIBMESH_DIM, N))) {}

  // 复制构造函数
  TypeNTensor (const TypeNTensor<N,T> &) : _coords(std::vector<T>(int_pow(LIBMESH_DIM, N))) {}

  // 赋值运算符，目前抛出未实现的异常
  TypeNTensor & operator = (const TypeNTensor<N,T> &) { libmesh_not_implemented(); return *this; }

  // 类型转换运算符，目前抛出未实现的异常
  operator TypeVector<T> () const { libmesh_not_implemented(); return 0; }
  operator VectorValue<T> () const { libmesh_not_implemented(); return 0; }

  // 类型转换运算符，目前抛出未实现的异常
  operator TypeTensor<T> () const { libmesh_not_implemented(); return 0; }
  operator TensorValue<T> () const { libmesh_not_implemented(); return 0; }

  // 析构函数
  ~TypeNTensor() = default;

  const TypeNTensor<N-1,T> slice (const unsigned int /*i*/) const
  {
    libmesh_not_implemented();
    return TypeNTensor<N-1,T>();
  }

  TypeNTensor<N-1,T> slice (const unsigned int /*i*/)
  {
    libmesh_not_implemented();
    return TypeNTensor<N-1,T>();
  }

  // 赋值运算符，目前抛出未实现的异常
  template <typename Scalar>
  typename boostcopy::enable_if_c<
    ScalarTraits<Scalar>::value,
    TypeNTensor &>::type
  operator = (const Scalar & libmesh_dbg_var(p))
  { libmesh_assert_equal_to (p, Scalar(0)); this->zero(); return *this; }

  // 加法运算符，目前抛出未实现的异常
  template<typename T2>
  TypeNTensor<N,typename CompareTypes<T, T2>::supertype>
  operator + (const TypeNTensor<N,T2> &) const
  {
    libmesh_not_implemented();
    return TypeNTensor<N,typename CompareTypes<T,T2>::supertype>();
  }

  // 复合赋值加法运算符，目前抛出未实现的异常
  template<typename T2>
  const TypeNTensor<N,T> & operator += (const TypeNTensor<N,T2> &/*rhs*/)
  {
    libmesh_not_implemented();
    return *this;
  }

  // 减法运算符，目前抛出未实现的异常
  template<typename T2>
  TypeNTensor<N,typename CompareTypes<T, T2>::supertype>
  operator - (const TypeNTensor<N,T2> &) const
  {
    libmesh_not_implemented();
    return TypeNTensor<N,typename CompareTypes<T,T2>::supertype>();
  }

  // 复合赋值减法运算符，目前抛出未实现的异常
  template<typename T2>
  const TypeNTensor<N,T> & operator -= (const TypeNTensor<N,T2> &)
  {
    libmesh_not_implemented();
    return *this;
  }

  // 取负运算符，目前抛出未实现的异常
  TypeNTensor<N,T> operator - () const
  {
    libmesh_not_implemented();
    return *this;
  }

  // 乘法运算符，目前抛出未实现的异常
  template <typename Scalar>
  typename boostcopy::enable_if_c<
    ScalarTraits<Scalar>::value,
    TypeNTensor<N,typename CompareTypes<T, Scalar>::supertype>>::type
  operator * (const Scalar) const
  {
    libmesh_not_implemented();
    return TypeNTensor<N,typename CompareTypes<T, Scalar>::supertype>();
  }

  // 复合赋值乘法运算符，目前抛出未实现的异常
  template <typename Scalar>
  const TypeNTensor<N,T> & operator *= (const Scalar)
  {
    libmesh_not_implemented();
    return *this;
  }

  // 除法运算符，目前抛出未实现的异常
  template <typename Scalar>
  typename boostcopy::enable_if_c<
    ScalarTraits<Scalar>::value,
    TypeNTensor<N,typename CompareTypes<T, Scalar>::supertype>>::type
  operator / (const Scalar) const
  {
    libmesh_not_implemented();
    return *this;
  }

  // 复合赋值除法运算符，目前抛出未实现的异常
  const TypeNTensor<N,T> & operator /= (const T)
  {
    libmesh_not_implemented();
    return *this;
  }

  template <typename T2>
  typename CompareTypes<T,T2>::supertype
  contract (const TypeNTensor<N,T2> &) const
  {
    libmesh_not_implemented();
    return 0;
  }

  auto norm_sq() const -> decltype(std::norm(T()))
  {
    libmesh_not_implemented();
    return 0.;
  }

  void zero() { libmesh_not_implemented(); }

  bool operator == (const TypeNTensor<N,T> & /*rhs*/) const
  {
    libmesh_not_implemented();
    return true;
  }

  bool operator < (const TypeNTensor<N,T> & /*rhs*/) const
  {
    libmesh_not_implemented();
    return false;
  }

  bool operator > (const TypeNTensor<N,T> & /*rhs*/) const
  {
    libmesh_not_implemented();
    return false;
  }

  void print(std::ostream & /*os = libMesh::out*/) const {}

  friend std::ostream & operator << (std::ostream & os,
                                     const TypeNTensor<N,T> & t)
  {
    t.print(os);
    return os;
  }

  template<typename T2>
  void add_scaled (const TypeNTensor<N, T2> &, const T &);

  std::vector<T> _coords;

private:
  static constexpr int int_pow(int b, int e)
  {
    return (e == 0) ? 1 : b * int_pow(b, e - 1);
  }
};


template<unsigned int N, typename T>
template<typename T2>
inline
void TypeNTensor<N, T>::add_scaled (const TypeNTensor<N, T2> & p, const T & factor)
{
  unsigned int size = int_pow(LIBMESH_DIM, N);
  for (unsigned int i = 0; i < size ; i++)
    _coords[i] += factor*p._coords[i];
}

template <unsigned int N, typename T, typename Scalar>
typename boostcopy::enable_if_c<
  ScalarTraits<Scalar>::value,
  TypeNTensor<N,typename CompareTypes<Scalar, T>::supertype>>::type
operator * (const Scalar &, const TypeNTensor<N, T> &)
{
  libmesh_not_implemented();
  return TypeNTensor<N,typename CompareTypes<Scalar, T>::supertype>();
}

template <unsigned int N, typename T, typename Scalar>
typename boostcopy::enable_if_c<
  ScalarTraits<Scalar>::value,
  TypeNTensor<N,typename CompareTypes<Scalar, T>::supertype>>::type
operator / (const Scalar &, const TypeNTensor<N, T> &)
{
  libmesh_not_implemented();
  return TypeNTensor<N,typename CompareTypes<Scalar, T>::supertype>();
}


} // namespace libMesh


#endif // LIBMESH_TYPE_N_TENSOR_H