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25 // 22 //
26 // G4Mag_UsualEqRhs implementation <<
27 // 23 //
28 // Created: J.Apostolakis, CERN - 13.01.1997 << 24 // $Id: G4Mag_UsualEqRhs.cc,v 1.8 2002/11/09 02:58:14 japost Exp $
29 // ------------------------------------------- << 25 // GEANT4 tag $Name: geant4-05-01 $
30 << 26 //
>> 27 //
>> 28 // This is the 'standard' right-hand side for the equation of motion
>> 29 // of a charged particle in a magnetic field.
>> 30 //
>> 31 // Initial version: J. Apostolakis, January 13th, 1997
>> 32 // Modified: J. Apostolakis, November 9th, 2002
>> 33 //
31 #include "G4Mag_UsualEqRhs.hh" 34 #include "G4Mag_UsualEqRhs.hh"
32 #include "G4MagneticField.hh" <<
33 <<
34 #include "globals.hh" <<
35 <<
36 G4Mag_UsualEqRhs::G4Mag_UsualEqRhs( G4Magnetic <<
37 : G4Mag_EqRhs( MagField ) <<
38 { <<
39 } <<
40 <<
41 G4Mag_UsualEqRhs::~G4Mag_UsualEqRhs() = defaul <<
42 35
43 void 36 void
44 G4Mag_UsualEqRhs::EvaluateRhsGivenB( const G4d 37 G4Mag_UsualEqRhs::EvaluateRhsGivenB( const G4double y[],
45 const G4d << 38 const G4double B[3],
46 G4d << 39 G4double dydx[] ) const
47 { 40 {
48 G4double momentum_mag_square = y[3]*y[3] + << 41 G4double momentum_mag_square = sqr(y[3]) + sqr(y[4]) + sqr(y[5]);
49 G4double inv_momentum_magnitude = 1.0 / std << 42 G4double inv_momentum_magnitude = 1.0 / sqrt( momentum_mag_square );
50 43
51 G4double cof = FCof()*inv_momentum_magnitud 44 G4double cof = FCof()*inv_momentum_magnitude;
52 45
53 dydx[0] = y[3]*inv_momentum_magnitude; 46 dydx[0] = y[3]*inv_momentum_magnitude; // (d/ds)x = Vx/V
54 dydx[1] = y[4]*inv_momentum_magnitude; 47 dydx[1] = y[4]*inv_momentum_magnitude; // (d/ds)y = Vy/V
55 dydx[2] = y[5]*inv_momentum_magnitude; 48 dydx[2] = y[5]*inv_momentum_magnitude; // (d/ds)z = Vz/V
56 49
57 dydx[3] = cof*(y[4]*B[2] - y[5]*B[1]) ; / 50 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]) ; / 51 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]) ; / 52 dydx[5] = cof*(y[3]*B[1] - y[4]*B[0]) ; // Az = a*(Vx*By - Vy*Bx)
60 53
61 return; << 54 return ;
62 } 55 }
63 56
64 void 57 void
65 G4Mag_UsualEqRhs::SetChargeMomentumMass( G4Cha << 58 G4Mag_UsualEqRhs::
66 G4dou << 59 SetChargeMomentumMass( G4double particleCharge, // in e+ units
67 G4dou << 60 G4double MomentumXc,
>> 61 G4double mass)
68 62
69 { 63 {
>> 64 fInvCurrentMomentumXc= 1.0 / MomentumXc;
70 G4Mag_EqRhs::SetChargeMomentumMass( particl 65 G4Mag_EqRhs::SetChargeMomentumMass( particleCharge, MomentumXc, mass);
71 } 66 }
72 67