Geant4  10.01
G4Mag_UsualEqRhs.cc
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27 // $Id: G4Mag_UsualEqRhs.cc 69699 2013-05-13 08:50:30Z gcosmo $
28 //
29 //
30 // This is the 'standard' right-hand side for the equation of motion
31 // of a charged particle in a magnetic field.
32 //
33 // Initial version: J. Apostolakis, January 13th, 1997
34 //
35 // --------------------------------------------------------------------
36 
37 #include "G4Mag_UsualEqRhs.hh"
38 #include "G4MagneticField.hh"
39 
40 #include "globals.hh" // For DBL_MAX
41 
43  : G4Mag_EqRhs( MagField ) {}
44 
46 
47 void
49  const G4double B[3],
50  G4double dydx[] ) const
51 {
52  G4double momentum_mag_square = y[3]*y[3] + y[4]*y[4] + y[5]*y[5];
53  G4double inv_momentum_magnitude = 1.0 / std::sqrt( momentum_mag_square );
54 
55  G4double cof = FCof()*inv_momentum_magnitude;
56 
57  dydx[0] = y[3]*inv_momentum_magnitude; // (d/ds)x = Vx/V
58  dydx[1] = y[4]*inv_momentum_magnitude; // (d/ds)y = Vy/V
59  dydx[2] = y[5]*inv_momentum_magnitude; // (d/ds)z = Vz/V
60 
61  dydx[3] = cof*(y[4]*B[2] - y[5]*B[1]) ; // Ax = a*(Vy*Bz - Vz*By)
62  dydx[4] = cof*(y[5]*B[0] - y[3]*B[2]) ; // Ay = a*(Vz*Bx - Vx*Bz)
63  dydx[5] = cof*(y[3]*B[1] - y[4]*B[0]) ; // Az = a*(Vx*By - Vy*Bx)
64 
65  return ;
66 }
67 
68 void
71  G4double MomentumXc,
72  G4double mass)
73 
74 {
75  G4Mag_EqRhs::SetChargeMomentumMass( particleCharge, MomentumXc, mass);
76 }
virtual ~G4Mag_UsualEqRhs()
G4double FCof() const
Definition: G4Mag_EqRhs.hh:84
virtual void SetChargeMomentumMass(G4ChargeState particleCharge, G4double MomentumXc, G4double mass)
virtual void SetChargeMomentumMass(G4ChargeState particleCharge, G4double MomentumXc, G4double mass)
Definition: G4Mag_EqRhs.cc:56
G4Mag_UsualEqRhs(G4MagneticField *MagField)
void EvaluateRhsGivenB(const G4double y[], const G4double B[3], G4double dydx[]) const
double G4double
Definition: G4Types.hh:76