dune-localfunctions  2.9.0
raviartthomas03dlocalinterpolation.hh
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1 // -*- tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*-
2 // vi: set et ts=4 sw=2 sts=2:
3 // SPDX-FileCopyrightInfo: Copyright (C) DUNE Project contributors, see file LICENSE.md in module root
4 // SPDX-License-Identifier: LicenseRef-GPL-2.0-only-with-DUNE-exception
5 #ifndef DUNE_LOCALFUNCTIONS_RAVIARTTHOMAS_RAVIARTTHOMAS03D_RAVIARTTHOMAS03DLOCALINTERPOLATION_HH
6 #define DUNE_LOCALFUNCTIONS_RAVIARTTHOMAS_RAVIARTTHOMAS03D_RAVIARTTHOMAS03DLOCALINTERPOLATION_HH
7 
8 #include <cmath>
9 #include <array>
10 #include <bitset>
11 #include <vector>
13 
14 namespace Dune
15 {
16  template<class LB>
18  {
19  public:
20 
22  RT03DLocalInterpolation (std::bitset<4> s = 0)
23  {
24  using std::sqrt;
25  for (std::size_t i=0; i<sign_.size(); i++)
26  sign_[i] = (s[i]) ? -1.0 : 1.0;
27 
28  m_[0] = {1/3.0, 1/3.0, 0.0};
29  m_[1] = {1/3.0, 0.0, 1/3.0};
30  m_[2] = { 0.0, 1/3.0, 1/3.0};
31  m_[3] = {1/3.0, 1/3.0, 1/3.0};
32  n_[0] = { 0.0, 0.0, -1.0};
33  n_[1] = { 0.0, -1.0, 0.0};
34  n_[2] = { -1.0, 0.0, 0.0};
35  n_[3] = {1.0/sqrt(3.0), 1.0/sqrt(3.0), 1.0/sqrt(3.0)};
36  c_[0] = sqrt(2.0);
37  c_[1] = sqrt(2.0);
38  c_[2] = sqrt(2.0);
39  c_[3] = sqrt(2.0)/sqrt(3.0);
40  }
41 
42  template<typename F, typename C>
43  void interpolate (const F& ff, std::vector<C>& out) const
44  {
45  // f gives v*outer normal at a point on the face!
46  auto&& f = Impl::makeFunctionWithCallOperator<typename LB::Traits::DomainType>(ff);
47 
48  out.resize(4);
49 
50  for (int i=0; i<4; i++)
51  {
52  auto y = f(m_[i]);
53  out[i] = (y[0]*n_[i][0]+y[1]*n_[i][1]+y[2]*n_[i][2])*sign_[i]/c_[i];
54  }
55  }
56 
57  private:
58  // Face orientations
59  std::array<typename LB::Traits::RangeFieldType,4> sign_;
60  // Face midpoints of the reference tetrahedron
61  std::array<typename LB::Traits::DomainType,4> m_;
62  // Unit outer normals of the reference tetrahedron
63  std::array<typename LB::Traits::DomainType,4> n_;
64  // Inverse triangle face area
65  std::array<typename LB::Traits::RangeFieldType,4> c_;
66  };
67 }
68 
69 #endif
Definition: bdfmcube.hh:18
Definition: raviartthomas03dlocalinterpolation.hh:18
void interpolate(const F &ff, std::vector< C > &out) const
Definition: raviartthomas03dlocalinterpolation.hh:43
RT03DLocalInterpolation(std::bitset< 4 > s=0)
Constructor with given set of face orientations.
Definition: raviartthomas03dlocalinterpolation.hh:22