DUNE PDELab (git)

raviartthomas03dlocalinterpolation.hh
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 © 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>
12
13namespace Dune
14{
15 template<class LB>
16 class RT03DLocalInterpolation
17 {
18 public:
19
25 RT03DLocalInterpolation (std::bitset<4> s = 0)
26 {
27 using std::sqrt;
28 for (std::size_t i=0; i<sign_.size(); i++)
29 sign_[i] = (s[i]) ? -1.0 : 1.0;
30
31 m_[0] = {1/3.0, 1/3.0, 0.0};
32 m_[1] = {1/3.0, 0.0, 1/3.0};
33 m_[2] = { 0.0, 1/3.0, 1/3.0};
34 m_[3] = {1/3.0, 1/3.0, 1/3.0};
35 n_[0] = { 0.0, 0.0, -1.0};
36 n_[1] = { 0.0, -1.0, 0.0};
37 n_[2] = { -1.0, 0.0, 0.0};
38 n_[3] = {1.0/sqrt(3.0), 1.0/sqrt(3.0), 1.0/sqrt(3.0)};
39 c_[0] = sqrt(2.0);
40 c_[1] = sqrt(2.0);
41 c_[2] = sqrt(2.0);
42 c_[3] = sqrt(2.0)/sqrt(3.0);
43 }
44
45 template<typename F, typename C>
46 void interpolate (const F& f, std::vector<C>& out) const
47 {
48 // f gives v*outer normal at a point on the face!
49
50 out.resize(4);
51
52 for (int i=0; i<4; i++)
53 {
54 auto y = f(m_[i]);
55 out[i] = (y[0]*n_[i][0]+y[1]*n_[i][1]+y[2]*n_[i][2])*sign_[i]/c_[i];
56 }
57 }
58
59 private:
60 // Face orientations
61 std::array<typename LB::Traits::RangeFieldType,4> sign_;
62 // Face midpoints of the reference tetrahedron
63 std::array<typename LB::Traits::DomainType,4> m_;
64 // Unit outer normals of the reference tetrahedron
65 std::array<typename LB::Traits::DomainType,4> n_;
66 // Inverse triangle face area
67 std::array<typename LB::Traits::RangeFieldType,4> c_;
68 };
69}
70
71#endif
void interpolate(const F &f, const GFS &gfs, XG &xg)
interpolation from a given grid function
Definition: interpolate.hh:177
RT03DLocalInterpolation(std::bitset< 4 > s=0)
Constructor with given set of face orientations.
Definition: raviartthomas03dlocalinterpolation.hh:25
Dune namespace.
Definition: alignedallocator.hh:13
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