v0.14.0
diffusion_Tensor1.hpp
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1 /* Computes 2*del^2 of a Tensor1_ptr but uses diagonal derivatives for
2  half of it. Yields a Tensor1. */
3 
4 #pragma once
5 
6 namespace FTensor
7 {
8  template <class T, int Dim, char i> class diffusion_Tensor1
9  {
11  const int di, dj, dk;
12  const double dx;
13 
14  public:
15  typename promote<T, double>::V operator()(const int N1) const
16  {
17  return ((*(a.ptr(N1) + di) - 2 * a(N1) + *(a.ptr(N1) - di))
18  + (*(a.ptr(N1) + dj) - 2 * a(N1) + *(a.ptr(N1) - dj))
19  + (*(a.ptr(N1) + dk) - 2 * a(N1) + *(a.ptr(N1) - dk))
20  + ((*(a.ptr(N1) + di + dj) + *(a.ptr(N1) + di - dj)
21  + *(a.ptr(N1) - di + dj) + *(a.ptr(N1) - di - dj)
22  - 4 * a(N1))
23  + (*(a.ptr(N1) + di + dk) + *(a.ptr(N1) + di - dk)
24  + *(a.ptr(N1) - di + dk) + *(a.ptr(N1) - di - dk)
25  - 4 * a(N1))
26  + (*(a.ptr(N1) + dj + dk) + *(a.ptr(N1) + dj - dk)
27  + *(a.ptr(N1) - dj + dk) + *(a.ptr(N1) - dj - dk)
28  - 4 * a(N1)))
29  / (std::sqrt(2.0)))
30  * dx * dx;
31  }
32  diffusion_Tensor1(const Tensor1<T *, Dim> &A, const int Di, const int Dj,
33  const int Dk, const double Dx)
34  : a(A), di(Di), dj(Dj), dk(Dk), dx(Dx)
35  {}
36  };
37 
38  template <class T, int Dim, char i>
40  typename promote<T, double>::V, Dim, i>
42  const int &di, const int &dj, const int &dk, const double &dx)
43  {
44  using Tensor_Expr = diffusion_Tensor1<T, Dim, i>;
46  Tensor_Expr(a, di, dj, dk, dx));
47  }
48 }
FTensor
JSON compatible output.
Definition: Christof_constructor.hpp:6
FTensor::Tensor1< T *, Dim >
FTensor::diffusion
promote< T, double >::V diffusion(const Tensor0< T * > &a, const int &di, const int &dj, const int &dk, const double &dx)
Definition: diffusion_Tensor0.hpp:10
A
constexpr AssemblyType A
Definition: operators_tests.cpp:30
FTensor::diffusion_Tensor1::operator()
promote< T, double >::V operator()(const int N1) const
Definition: diffusion_Tensor1.hpp:15
FTensor::diffusion_Tensor1::dx
const double dx
Definition: diffusion_Tensor1.hpp:12
FTensor::diffusion_Tensor1::di
const int di
Definition: diffusion_Tensor1.hpp:11
FTensor::diffusion_Tensor1::diffusion_Tensor1
diffusion_Tensor1(const Tensor1< T *, Dim > &A, const int Di, const int Dj, const int Dk, const double Dx)
Definition: diffusion_Tensor1.hpp:32
FTensor::Tensor1_Expr
Definition: Tensor1_Expr.hpp:27
a
constexpr double a
Definition: approx_sphere.cpp:30
FTensor::promote::V
T1 V
Definition: promote.hpp:17
FTensor::diffusion_Tensor1::a
const Tensor1< T *, Dim > & a
Definition: diffusion_Tensor1.hpp:10
FTensor::diffusion_Tensor1
Definition: diffusion_Tensor1.hpp:8
FTensor::diffusion_Tensor1::dk
const int dk
Definition: diffusion_Tensor1.hpp:11
FTensor::diffusion_Tensor1::dj
const int dj
Definition: diffusion_Tensor1.hpp:11
i
FTensor::Index< 'i', SPACE_DIM > i
Definition: hcurl_divergence_operator_2d.cpp:27
FTensor::Index
Definition: Index.hpp:23
Tensor1_Expr
Definition: single.cpp:11