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25 // 25 //
26 // G4Mag_UsualEqRhs implementation <<
27 // 26 //
28 // Created: J.Apostolakis, CERN - 13.01.1997 << 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 //
29 // ------------------------------------------- 35 // --------------------------------------------------------------------
30 36
31 #include "G4Mag_UsualEqRhs.hh" 37 #include "G4Mag_UsualEqRhs.hh"
32 #include "G4MagneticField.hh" 38 #include "G4MagneticField.hh"
33 39
34 #include "globals.hh" << 40 #include "globals.hh" // For DBL_MAX
35 41
36 G4Mag_UsualEqRhs::G4Mag_UsualEqRhs( G4Magnetic 42 G4Mag_UsualEqRhs::G4Mag_UsualEqRhs( G4MagneticField* MagField )
37 : G4Mag_EqRhs( MagField ) << 43 : G4Mag_EqRhs( MagField ) {}
38 { <<
39 } <<
40 44
41 G4Mag_UsualEqRhs::~G4Mag_UsualEqRhs() = defaul << 45 G4Mag_UsualEqRhs::~G4Mag_UsualEqRhs() {}
42 46
43 void 47 void
44 G4Mag_UsualEqRhs::EvaluateRhsGivenB( const G4d 48 G4Mag_UsualEqRhs::EvaluateRhsGivenB( const G4double y[],
45 const G4d << 49 const G4double B[3],
46 G4d << 50 G4double dydx[] ) const
47 { 51 {
48 G4double momentum_mag_square = y[3]*y[3] + 52 G4double momentum_mag_square = y[3]*y[3] + y[4]*y[4] + y[5]*y[5];
49 G4double inv_momentum_magnitude = 1.0 / std 53 G4double inv_momentum_magnitude = 1.0 / std::sqrt( momentum_mag_square );
50 54
51 G4double cof = FCof()*inv_momentum_magnitud 55 G4double cof = FCof()*inv_momentum_magnitude;
52 56
53 dydx[0] = y[3]*inv_momentum_magnitude; 57 dydx[0] = y[3]*inv_momentum_magnitude; // (d/ds)x = Vx/V
54 dydx[1] = y[4]*inv_momentum_magnitude; 58 dydx[1] = y[4]*inv_momentum_magnitude; // (d/ds)y = Vy/V
55 dydx[2] = y[5]*inv_momentum_magnitude; 59 dydx[2] = y[5]*inv_momentum_magnitude; // (d/ds)z = Vz/V
56 60
57 dydx[3] = cof*(y[4]*B[2] - y[5]*B[1]) ; / 61 dydx[3] = cof*(y[4]*B[2] - y[5]*B[1]) ; // Ax = a*(Vy*Bz - Vz*By)
58 dydx[4] = cof*(y[5]*B[0] - y[3]*B[2]) ; / 62 dydx[4] = cof*(y[5]*B[0] - y[3]*B[2]) ; // Ay = a*(Vz*Bx - Vx*Bz)
59 dydx[5] = cof*(y[3]*B[1] - y[4]*B[0]) ; / 63 dydx[5] = cof*(y[3]*B[1] - y[4]*B[0]) ; // Az = a*(Vx*By - Vy*Bx)
60 64
61 return; << 65 return ;
62 } 66 }
63 67
64 void 68 void
65 G4Mag_UsualEqRhs::SetChargeMomentumMass( G4Cha << 69 G4Mag_UsualEqRhs::
66 G4dou << 70 SetChargeMomentumMass( G4ChargeState particleCharge,
67 G4dou << 71 G4double MomentumXc,
>> 72 G4double mass)
68 73
69 { 74 {
70 G4Mag_EqRhs::SetChargeMomentumMass( particl 75 G4Mag_EqRhs::SetChargeMomentumMass( particleCharge, MomentumXc, mass);
71 } 76 }
72 77