Gabriele Cosmo
39 lines
1.4 KiB
C++
39 lines
1.4 KiB
C++
// This code implementation is the intellectual property of
|
|
// the RD44 GEANT4 collaboration.
|
|
//
|
|
// By copying, distributing or modifying the Program (or any work
|
|
// based on the Program) you indicate your acceptance of this statement,
|
|
// and all its terms.
|
|
//
|
|
// $Id: G4Mag_UsualEqRhs.cc,v 2.2 1998/11/18 21:11:38 japost Exp $
|
|
// GEANT4 tag $Name: geant4-00 $
|
|
//
|
|
//
|
|
// This is the standard right-hand side for equation of motion.
|
|
//
|
|
// The only case another is required is when using a moving reference
|
|
// frame ... or extending the class to include additional Forces,
|
|
// eg an electric field
|
|
//
|
|
// J. Apostolakis, January 13th, 1997
|
|
//
|
|
#include "G4Mag_UsualEqRhs.hh"
|
|
|
|
void
|
|
G4Mag_UsualEqRhs::EvaluateRhsGivenB( const G4double y[],
|
|
const G4double B[3],
|
|
G4double dydx[] ) const
|
|
{
|
|
G4double velocity_mag_square = sqr(y[3]) + sqr(y[4]) + sqr(y[5]);
|
|
G4double inv_velocity_magnitude = 1.0 / sqrt( velocity_mag_square );
|
|
|
|
dydx[0] = y[3] * inv_velocity_magnitude; // (d/ds)x = Vx/V
|
|
dydx[1] = y[4] * inv_velocity_magnitude; // (d/ds)y = Vy/V
|
|
dydx[2] = y[5] * inv_velocity_magnitude; // (d/ds)z = Vz/V
|
|
dydx[3] = FCof()*(y[4]*B[2] - y[5]*B[1]) ; // Ax = a*(Vy*Bz - Vz*By)
|
|
dydx[4] = FCof()*(y[5]*B[0] - y[3]*B[2]) ; // Ay = a*(Vz*Bx - Vx*Bz)
|
|
dydx[5] = FCof()*(y[3]*B[1] - y[4]*B[0]) ; // Az = a*(Vx*By - Vy*Bx)
|
|
|
|
return ;
|
|
}
|