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periodic.hpp
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1 // This file is part of the Acts project.
2 //
3 // Copyright (C) 2016-2018 CERN for the benefit of the Acts project
4 //
5 // This Source Code Form is subject to the terms of the Mozilla Public
6 // License, v. 2.0. If a copy of the MPL was not distributed with this
7 // file, You can obtain one at http://mozilla.org/MPL/2.0/.
8 
9 #pragma once
10 #include <cmath>
11 
12 namespace Acts {
13 namespace detail {
14 
16 template <typename T>
17 inline T wrap_periodic(T value, T start, T range) {
18  using std::floor;
19  // only wrap if really necessary
20  T diff = value - start;
21  return ((0 <= diff) && (diff < range))
22  ? value
23  : (value - range * floor(diff / range));
24 }
25 
27 template <typename T>
28 inline T radian_pos(T x) {
29  return wrap_periodic<T>(x, T(0), T(2 * M_PI));
30 }
31 
33 template <typename T>
34 inline T radian_sym(T x) {
35  return wrap_periodic<T>(x, T(-M_PI), T(2 * M_PI));
36 }
37 
41 template <typename T>
42 inline std::pair<T, T> ensureThetaBounds(T phi, T theta) {
43  T tmpPhi = radian_sym(phi);
44 
45  T tmpTht = std::fmod(theta, 2 * M_PI);
46  if (tmpTht < -M_PI) {
47  tmpTht = std::abs(tmpTht + 2 * M_PI);
48  } else if (tmpTht < 0) {
49  tmpTht *= -1;
50  tmpPhi += M_PI;
51  tmpPhi = tmpPhi > M_PI ? tmpPhi - 2 * M_PI : tmpPhi;
52  }
53  if (tmpTht > M_PI) {
54  tmpTht = 2 * M_PI - tmpTht;
55  tmpPhi += M_PI;
56  tmpPhi = tmpPhi > M_PI ? (tmpPhi - 2 * M_PI) : tmpPhi;
57  }
58 
59  return std::pair<T, T>(tmpPhi, tmpTht);
60 }
61 
62 } // namespace detail
63 } // namespace Acts