text: //
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  /// \file exoticphysics/monopole/src/G4MonopoleEquation.cc
  /// \brief Implementation of the G4MonopoleEquation class
  //
  // $Id: G4MonopoleEquation.cc 69705 2013-05-13 09:09:52Z gcosmo $
  //
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  //
  //
  // class G4MonopoleEquation
  //
  // Class description:
  //
  //
  //  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
  //
  //  10.11.98   V.Grichine
  //
  //  30.04.10   S.Burdin (modified to use for the monopole trajectories).
  //
  //  15.06.10   B.Bozsogi (replaced the hardcoded magnetic charge with
  //                        the one passed by G4MonopoleTransportation)
  //                       +workaround to pass the electric charge.
  // 
  //  12.07.10  S.Burdin (added equations for the electric charges)
  // -------------------------------------------------------------------
  
  #include "SimG4Core/MagneticField/interface/G4MonopoleEquation.hh"
  #include "globals.hh"
  #include "G4PhysicalConstants.hh"
  #include "G4SystemOfUnits.hh"
  #include <iomanip>
  
  //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
  
  G4MonopoleEquation::G4MonopoleEquation(G4ElectroMagneticField *emField )
        : G4EquationOfMotion( emField ) 
  {}
  
  //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
  
  G4MonopoleEquation::~G4MonopoleEquation()
  {}
  
  //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
  
  void  
  G4MonopoleEquation::SetChargeMomentumMass( G4ChargeState particleChargeState, 
                                             G4double      ,           // momentum, 
                                             G4double particleMass)
  {
     G4double particleMagneticCharge= particleChargeState.MagneticCharge(); 
     G4double particleElectricCharge= particleChargeState.GetCharge(); 
  
    //   fElCharge = particleElectricCharge;
    fElCharge =eplus* particleElectricCharge*c_light;
     
    fMagCharge =  eplus*particleMagneticCharge*c_light ;
  
    // G4cout << " G4MonopoleEquation: ElectricCharge=" << particleElectricCharge
    //           << "; MagneticCharge=" << particleMagneticCharge
    //           << G4endl;
   
    fMassCof = particleMass*particleMass ; 
  }
  
  //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
  
  void
  G4MonopoleEquation::EvaluateRhsGivenB(const G4double y[],
                                        const G4double Field[],
                                        G4double dydx[] ) const
  {
    // Components of y:
    //    0-2 dr/ds, 
    //    3-5 dp/ds - momentum derivatives 
  
    G4double pSquared = y[3]*y[3] + y[4]*y[4] + y[5]*y[5] ;
  
    G4double Energy   = std::sqrt( pSquared + fMassCof );
     
    G4double pModuleInverse  = 1.0/std::sqrt(pSquared);
  
    G4double inverse_velocity = Energy * pModuleInverse / c_light;
  
    G4double cofEl     = fElCharge * pModuleInverse ;
    G4double cofMag = fMagCharge * Energy * pModuleInverse; 
  
  
    dydx[0] = y[3]*pModuleInverse ;                         
    dydx[1] = y[4]*pModuleInverse ;                         
    dydx[2] = y[5]*pModuleInverse ;                    
       
    // G4double magCharge = twopi * hbar_Planck / (eplus * mu0);    
    // magnetic charge in SI units A*m convention
    //  see http://en.wikipedia.org/wiki/Magnetic_monopole   
    //   G4cout  << "Magnetic charge:  " << magCharge << G4endl;   
    // dp/ds = dp/dt * dt/ds = dp/dt / v = Force / velocity
    // dydx[3] = fMagCharge * Field[0]  * inverse_velocity  * c_light;    
    // multiplied by c_light to convert to MeV/mm
    //     dydx[4] = fMagCharge * Field[1]  * inverse_velocity  * c_light; 
    //     dydx[5] = fMagCharge * Field[2]  * inverse_velocity  * c_light; 
        
    dydx[3] = cofMag * Field[0] + cofEl * (y[4]*Field[2] - y[5]*Field[1]);   
    dydx[4] = cofMag * Field[1] + cofEl * (y[5]*Field[0] - y[3]*Field[2]); 
    dydx[5] = cofMag * Field[2] + cofEl * (y[3]*Field[1] - y[4]*Field[0]); 
     
    //        G4cout << std::setprecision(5)<< "E=" << Energy
    //               << "; p="<< 1/pModuleInverse
    //               << "; mC="<< magCharge
    //               <<"; x=" << y[0]
    //               <<"; y=" << y[1]
    //               <<"; z=" << y[2]
    //               <<"; dydx[3]=" << dydx[3]
    //               <<"; dydx[4]=" << dydx[4]
    //               <<"; dydx[5]=" << dydx[5]
    //               << G4endl;
  
    dydx[6] = 0.;//not used
     
    // Lab Time of flight
    dydx[7] = inverse_velocity;
    return;
  }
  
  //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
  