Geant4  9.6.p02
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CCalMagneticField.cc
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27 // File: CCalMagneticField.cc
28 // Description: User Field class implementation.
30 #include <fstream>
31 
32 #include "CCalMagneticField.hh"
33 #include "CCalutils.hh"
34 #include "G4SystemOfUnits.hh"
35 #include "G4FieldManager.hh"
36 
37 //#define ddebug
38 //#define debug
39 
40 //Constructor and destructor:
41 
43  fval(0), pos(0), slope(0), intercept(0) {
44 
45  //Let's open the file
46  G4cout << " ==> Opening file " << filename << " to read magnetic field..."
47  << G4endl;
48  G4String pathName = getenv("CCAL_GLOBALPATH");
49  std::ifstream is;
50  bool ok = openGeomFile(is, pathName, filename);
51 
52  if (ok) {
53  findDO(is, G4String("FLDM"));
54  is >> fval >> npts >> xoff;
55 #ifdef debug
56  G4cout << "Field value " << fval << " # points " << npts << " offset in x "
57  << xoff*mm << G4endl;
58 #endif
59 
60  if (npts > 0) {
61  pos = new G4double[npts];
62  slope = new G4double[npts];
63  intercept = new G4double[npts];
64 
65  for (G4int i = 0; i < npts; i++) {
66  is >> pos[i] >> slope[i] >> intercept[i];
67 #ifdef debug
68  G4cout << tab << "Position " << i << " " << pos[i] << " Slope "
69  << slope[i] << " Intercept " << intercept[i] << G4endl;
70 #endif
71  }
72  }
73 
75  // Close the file
76  G4cout << " ==> Closing file " << filename << G4endl;
77  is.close();
78  }
79 }
80 
81 
83  if (pos)
84  delete[] pos;
85  if (slope)
86  delete[] slope;
87  if (intercept)
88  delete[] intercept;
89 }
90 
91 
92 // Member functions
93 
94 void CCalMagneticField::MagneticField(const double x[3], double B[3]) const {
95 
96  G4int i=0;
97  for (i=0; i<2; i++) {
98  B[i] = 0*kilogauss;
99  }
100 
101  G4double m1=0, c1=0;
102  G4double xnew = x[0]/mm + xoff;
103  if (npts > 0) {
104  for (i=0; i<npts; i++) {
105  if (xnew > pos[i]*mm) {
106  m1 = slope[i];
107  c1 = intercept[i];
108  }
109  }
110  }
111  G4double scor = c1 + m*xnew;
112  if (scor < 0.) scor = 0.;
113  if (scor > 1.) scor = 1.0;
114 
115  B[2] = scor*fval*kilogauss;
116 #ifdef ddebug
117  G4cout << "Field at x: " << x[0]/mm << "mm (" << xnew << ") = " << B[2]/tesla
118  << "T (m = " << m1 << ", c = " << c1 << ", scale = " << scor << ")"
119  << G4endl;
120 #endif
121 }
122 
123 
125 MagneticField(const CLHEP::Hep3Vector point) const {
126 
127  G4double x[3],B[3];
129 
130  x[0] = point.x();
131  x[1] = point.y();
132  x[2] = point.z();
134  v.setX(B[0]);
135  v.setY(B[1]);
136  v.setZ(B[2]);
137  return v;
138 }
139 
140 
141 void CCalMagneticField::GetFieldValue(const double x[3], double* B) const {
143 }
144