dune-localfunctions  2.7.1
raviartthomas02dlocalinterpolation.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 #ifndef DUNE_RT02DLOCALINTERPOLATION_HH
4 #define DUNE_RT02DLOCALINTERPOLATION_HH
5 
6 #include <cmath>
7 #include <array>
8 #include <bitset>
9 #include <vector>
11 
12 namespace Dune
13 {
14  template<class LB>
16  {
17  public:
18 
20  RT02DLocalInterpolation (std::bitset<3> s = 0)
21  {
22  for (std::size_t i=0; i<sign_.size(); i++)
23  sign_[i] = (s[i]) ? -1.0 : 1.0;
24 
25  m_[0] = {0.5, 0.0};
26  m_[1] = {0.0, 0.5};
27  m_[2] = {0.5, 0.5};
28  n_[0] = {0.0, -1.0};
29  n_[1] = {-1.0, 0.0};
30  n_[2] = {1.0/sqrt(2.0), 1.0/sqrt(2.0)};
31  c_[0] = ( 0.5*n_[0][0] - 1.0*n_[0][1]);
32  c_[1] = (-1.0*n_[1][0] + 0.5*n_[1][1]);
33  c_[2] = ( 0.5*n_[2][0] + 0.5*n_[2][1]);
34  }
35 
36  template<typename F, typename C>
37  void interpolate (const F& ff, std::vector<C>& out) const
38  {
39  // f gives v*outer normal at a point on the edge!
40  auto&& f = Impl::makeFunctionWithCallOperator<typename LB::Traits::DomainType>(ff);
41 
42  out.resize(3);
43 
44  for (int i=0; i<3; i++)
45  {
46  auto y = f(m_[i]);
47  out[i] = (y[0]*n_[i][0]+y[1]*n_[i][1])*sign_[i]/c_[i];
48  }
49  }
50 
51  private:
52  // Edge orientations
53  std::array<typename LB::Traits::RangeFieldType,3> sign_;
54  // Edge midpoints of the reference triangle
55  std::array<typename LB::Traits::DomainType,3> m_;
56  // Unit outer normals of the reference triangle
57  std::array<typename LB::Traits::DomainType,3> n_;
58  // Inverse triangle edge length
59  std::array<typename LB::Traits::RangeFieldType,3> c_;
60  };
61 }
62 
63 #endif
Definition: bdfmcube.hh:16
Definition: raviartthomas02dlocalinterpolation.hh:16
void interpolate(const F &ff, std::vector< C > &out) const
Definition: raviartthomas02dlocalinterpolation.hh:37
RT02DLocalInterpolation(std::bitset< 3 > s=0)
Constructor with given set of edge orientations.
Definition: raviartthomas02dlocalinterpolation.hh:20