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BFieldUtils.cpp
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1 // This file is part of the Acts project.
2 //
3 // Copyright (C) 2017 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 #include "ACTFW/Plugins/BField/BFieldUtils.hpp"
10 
11 #include <fstream>
12 
13 #include "Acts/MagneticField/BFieldMapUtils.hpp"
14 #include "Acts/Utilities/detail/Axis.hpp"
15 #include "Acts/Utilities/detail/Grid.hpp"
16 #include "TFile.h"
17 #include "TROOT.h"
18 #include "TTree.h"
19 
20 Acts::InterpolatedBFieldMapper<
21  Acts::detail::Grid<Acts::Vector2D, Acts::detail::EquidistantAxis,
22  Acts::detail::EquidistantAxis>>
23 FW::BField::txt::fieldMapperRZ(
24  std::function<size_t(std::array<size_t, 2> binsRZ,
25  std::array<size_t, 2> nBinsRZ)>
26  localToGlobalBin,
27  std::string fieldMapFile, double lengthUnit, double BFieldUnit,
28  size_t nPoints, bool firstQuadrant) {
30  // Grid position points in r and z
31  std::vector<double> rPos;
32  std::vector<double> zPos;
33  // components of magnetic field on grid points
34  std::vector<Acts::Vector2D> bField;
35  // reserve estimated size
36  rPos.reserve(nPoints);
37  zPos.reserve(nPoints);
38  bField.reserve(nPoints);
39  // [1] Read in file and fill values
40  std::ifstream map_file(fieldMapFile.c_str(), std::ios::in);
41  std::string line;
42  double r = 0., z = 0.;
43  double br = 0., bz = 0.;
44  while (std::getline(map_file, line)) {
45  if (line.empty() || line[0] == '%' || line[0] == '#' ||
46  line.find_first_not_of(' ') == std::string::npos)
47  continue;
48 
49  std::istringstream tmp(line);
50  tmp >> r >> z >> br >> bz;
51  rPos.push_back(r);
52  zPos.push_back(z);
53  bField.push_back(Acts::Vector2D(br, bz));
54  }
55  map_file.close();
57  return Acts::fieldMapperRZ(localToGlobalBin, rPos, zPos, bField, lengthUnit,
58  BFieldUnit, firstQuadrant);
59 }
60 
61 Acts::InterpolatedBFieldMapper<Acts::detail::Grid<
62  Acts::Vector3D, Acts::detail::EquidistantAxis,
63  Acts::detail::EquidistantAxis, Acts::detail::EquidistantAxis>>
64 FW::BField::txt::fieldMapperXYZ(
65  std::function<size_t(std::array<size_t, 3> binsXYZ,
66  std::array<size_t, 3> nBinsXYZ)>
67  localToGlobalBin,
68  std::string fieldMapFile, double lengthUnit, double BFieldUnit,
69  size_t nPoints, bool firstOctant) {
71  // Grid position points in x, y and z
72  std::vector<double> xPos;
73  std::vector<double> yPos;
74  std::vector<double> zPos;
75  // components of magnetic field on grid points
76  std::vector<Acts::Vector3D> bField;
77  // reserve estimated size
78  xPos.reserve(nPoints);
79  yPos.reserve(nPoints);
80  zPos.reserve(nPoints);
81  bField.reserve(nPoints);
82  // [1] Read in file and fill values
83  std::ifstream map_file(fieldMapFile.c_str(), std::ios::in);
84  std::string line;
85  double x = 0., y = 0., z = 0.;
86  double bx = 0., by = 0., bz = 0.;
87  while (std::getline(map_file, line)) {
88  if (line.empty() || line[0] == '%' || line[0] == '#' ||
89  line.find_first_not_of(' ') == std::string::npos)
90  continue;
91 
92  std::istringstream tmp(line);
93  tmp >> x >> y >> z >> bx >> by >> bz;
94  xPos.push_back(x);
95  yPos.push_back(y);
96  zPos.push_back(z);
97  bField.push_back(Acts::Vector3D(bx, by, bz));
98  }
99  map_file.close();
100 
101  return Acts::fieldMapperXYZ(localToGlobalBin, xPos, yPos, zPos, bField,
102  lengthUnit, BFieldUnit, firstOctant);
103 }
104 
105 Acts::InterpolatedBFieldMapper<
106  Acts::detail::Grid<Acts::Vector2D, Acts::detail::EquidistantAxis,
107  Acts::detail::EquidistantAxis>>
108 FW::BField::root::fieldMapperRZ(
109  std::function<size_t(std::array<size_t, 2> binsRZ,
110  std::array<size_t, 2> nBinsRZ)>
111  localToGlobalBin,
112  std::string fieldMapFile, std::string treeName, double lengthUnit,
113  double BFieldUnit, bool firstQuadrant) {
115  // Grid position points in r and z
116  std::vector<double> rPos;
117  std::vector<double> zPos;
118  // components of magnetic field on grid points
119  std::vector<Acts::Vector2D> bField;
120  // [1] Read in file and fill values
121  TFile* inputFile = TFile::Open(fieldMapFile.c_str());
122  TTree* tree = (TTree*)inputFile->Get(treeName.c_str());
123  Int_t entries = tree->GetEntries();
124 
125  double r, z;
126  double Br, Bz;
127 
128  tree->SetBranchAddress("r", &r);
129  tree->SetBranchAddress("z", &z);
130 
131  tree->SetBranchAddress("Br", &Br);
132  tree->SetBranchAddress("Bz", &Bz);
133 
134  // reserve size
135  rPos.reserve(entries);
136  zPos.reserve(entries);
137  bField.reserve(entries);
138 
139  for (int i = 0; i < entries; i++) {
140  tree->GetEvent(i);
141  rPos.push_back(r);
142  zPos.push_back(z);
143  bField.push_back(Acts::Vector2D(Br, Bz));
144  }
145  inputFile->Close();
147  return Acts::fieldMapperRZ(localToGlobalBin, rPos, zPos, bField, lengthUnit,
148  BFieldUnit, firstQuadrant);
149 }
150 
151 Acts::InterpolatedBFieldMapper<Acts::detail::Grid<
152  Acts::Vector3D, Acts::detail::EquidistantAxis,
153  Acts::detail::EquidistantAxis, Acts::detail::EquidistantAxis>>
154 FW::BField::root::fieldMapperXYZ(
155  std::function<size_t(std::array<size_t, 3> binsXYZ,
156  std::array<size_t, 3> nBinsXYZ)>
157  localToGlobalBin,
158  std::string fieldMapFile, std::string treeName, double lengthUnit,
159  double BFieldUnit, bool firstOctant) {
161  // Grid position points in x, y and z
162  std::vector<double> xPos;
163  std::vector<double> yPos;
164  std::vector<double> zPos;
165  // components of magnetic field on grid points
166  std::vector<Acts::Vector3D> bField;
167  // [1] Read in file and fill values
168  TFile* inputFile = TFile::Open(fieldMapFile.c_str());
169  TTree* tree = (TTree*)inputFile->Get(treeName.c_str());
170  Int_t entries = tree->GetEntries();
171 
172  double x, y, z;
173  double Bx, By, Bz;
174 
175  tree->SetBranchAddress("x", &x);
176  tree->SetBranchAddress("y", &y);
177  tree->SetBranchAddress("z", &z);
178 
179  tree->SetBranchAddress("Bx", &Bx);
180  tree->SetBranchAddress("By", &By);
181  tree->SetBranchAddress("Bz", &Bz);
182 
183  // reserve size
184  xPos.reserve(entries);
185  yPos.reserve(entries);
186  zPos.reserve(entries);
187  bField.reserve(entries);
188 
189  for (int i = 0; i < entries; i++) {
190  tree->GetEvent(i);
191  xPos.push_back(x);
192  yPos.push_back(y);
193  zPos.push_back(z);
194  bField.push_back(Acts::Vector3D(Bx, By, Bz));
195  }
196  inputFile->Close();
197 
198  return Acts::fieldMapperXYZ(localToGlobalBin, xPos, yPos, zPos, bField,
199  lengthUnit, BFieldUnit, firstOctant);
200 }