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CCalMagneticField.cc
Go to the documentation of this file. Or view the newest version in sPHENIX GitHub for file CCalMagneticField.cc
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25 //
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 #ifdef debug
46  fVerbosity = 1;
47 #else
48  fVerbosity = 0;
49 #endif
50 
51  //Let's open the file
52  G4cout << " ==> Opening file " << filename << " to read magnetic field..."
53  << G4endl;
54  G4String pathName = std::getenv("CCAL_GLOBALPATH");
55  std::ifstream is;
56  G4bool ok = openGeomFile(is, pathName, filename);
57 
58  if (ok) {
59  findDO(is, G4String("FLDM"));
60  is >> fval >> npts >> xoff;
61 
62  if (fVerbosity)
63  G4cout << "Field value " << fval << " # points " << npts <<
64  " offset in x "
65  << xoff*mm << G4endl;
66 
67  if (npts > 0) {
68  pos = new G4double[npts];
69  slope = new G4double[npts];
70  intercept = new G4double[npts];
71 
72  for (G4int i = 0; i < npts; i++) {
73  is >> pos[i] >> slope[i] >> intercept[i];
74  if (fVerbosity)
75  G4cout << tab << "Position " << i << " " << pos[i] << " Slope "
76  << slope[i] << " Intercept " << intercept[i] << G4endl;
77  }
78  }
79 
81  // Close the file
82  G4cout << " ==> Closing file " << filename << G4endl;
83  is.close();
84  }
85 }
86 
87 
89  if (pos)
90  delete[] pos;
91  if (slope)
92  delete[] slope;
93  if (intercept)
94  delete[] intercept;
95 }
96 
97 
98 // Member functions
99 
101 {
102  G4int i=0;
103  for (i=0; i<2; i++) {
104  B[i] = 0*kilogauss;
105  }
106 
107  G4double m1=0;
108  G4double c1=0;
109  G4double xnew = x[0]/mm + xoff;
110  if (npts > 0) {
111  for (i=0; i<npts; i++) {
112  if (xnew > pos[i]*mm) {
113  m1 = slope[i];
114  c1 = intercept[i];
115  }
116  }
117  }
118  G4double scor = c1 + m*xnew;
119  if (scor < 0.) scor = 0.;
120  if (scor > 1.) scor = 1.0;
121 
122  B[2] = scor*fval*kilogauss;
123  if (fVerbosity)
124  {
125 
126  G4cout << "Field at x: " << x[0]/mm << "mm (" << xnew << ") = " <<
127  B[2]/tesla
128  << "T (m = " << m1 << ", c = " <<
129  c1 << ", scale = " << scor << ")"
130  << G4endl;
131  }
132 }
133 
134 
137 
138  G4double x[3],B[3];
140 
141  x[0] = point.x();
142  x[1] = point.y();
143  x[2] = point.z();
145  v.setX(B[0]);
146  v.setY(B[1]);
147  v.setZ(B[2]);
148  return v;
149 }
150 
151 
154 }
155