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25 // 25 //
26 // G4ErrorMag_UsualEqRhs implementation <<
27 // 26 //
28 // Created: P.Arce, September 2004. << 27 //
>> 28 //
>> 29 // --------------------------------------------------------------------
>> 30 // GEANT 4 class implementation file
29 // ------------------------------------------- 31 // --------------------------------------------------------------------
30 32
31 #include "G4ErrorMag_UsualEqRhs.hh" 33 #include "G4ErrorMag_UsualEqRhs.hh"
32 #include "G4ErrorPropagatorData.hh" 34 #include "G4ErrorPropagatorData.hh"
33 35
34 //-------------------------------------------- 36 //---------------------------------------------------------------------
35 37
36 G4ErrorMag_UsualEqRhs::G4ErrorMag_UsualEqRhs( 38 G4ErrorMag_UsualEqRhs::G4ErrorMag_UsualEqRhs( G4MagneticField* MagField )
37 : G4Mag_UsualEqRhs( MagField ) 39 : G4Mag_UsualEqRhs( MagField )
38 { 40 {
39 } 41 }
40 42
41 G4ErrorMag_UsualEqRhs::~G4ErrorMag_UsualEqRhs( << 43 G4ErrorMag_UsualEqRhs::~G4ErrorMag_UsualEqRhs()
>> 44 {
>> 45 }
42 46
43 //-------------------------------------------- 47 //---------------------------------------------------------------------
44 <<
45 void 48 void
46 G4ErrorMag_UsualEqRhs::EvaluateRhsGivenB( cons 49 G4ErrorMag_UsualEqRhs::EvaluateRhsGivenB( const G4double y[],
47 cons 50 const G4double B[3],
48 51 G4double dydx[] ) const
49 { 52 {
50 53
51 G4Mag_UsualEqRhs::EvaluateRhsGivenB(y, B, dy 54 G4Mag_UsualEqRhs::EvaluateRhsGivenB(y, B, dydx );
52 55
53 if(G4ErrorPropagatorData::GetErrorPropagator 56 if(G4ErrorPropagatorData::GetErrorPropagatorData()->GetMode()
54 == G4ErrorMode_PropBackwards) 57 == G4ErrorMode_PropBackwards)
55 { 58 {
56 G4double momentum_mag_square = sqr(y[3]) + 59 G4double momentum_mag_square = sqr(y[3]) + sqr(y[4]) + sqr(y[5]);
57 G4double inv_momentum_magnitude = 1.0 / st 60 G4double inv_momentum_magnitude = 1.0 / std::sqrt( momentum_mag_square );
58 61
59 G4double cof = FCof()*inv_momentum_magnitu 62 G4double cof = FCof()*inv_momentum_magnitude;
60 63
61 dydx[3] = cof*(y[4]*(-B[2]) - y[5]*(-B[1]) 64 dydx[3] = cof*(y[4]*(-B[2]) - y[5]*(-B[1])) ;
62 dydx[4] = cof*(y[5]*(-B[0]) - y[3]*(-B[2]) 65 dydx[4] = cof*(y[5]*(-B[0]) - y[3]*(-B[2])) ;
63 dydx[5] = cof*(y[3]*(-B[1]) - y[4]*(-B[0]) 66 dydx[5] = cof*(y[3]*(-B[1]) - y[4]*(-B[0])) ;
64 } 67 }
65 return; 68 return;
66 } 69 }
67 70