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// $Id: G4MagHelicalStepper.icc,v 1.13 2007/05/18 15:45:15 tnikitin Exp $
// GEANT4 tag $Name:  $
//
// Linear Step in regions of no field
//
// --------------------------------------------------------------------

inline void
G4MagHelicalStepper::LinearStep( const G4double  yIn[],
                                       G4double  h,
                                       G4double  yLinear[]) const
{
  G4double  momentum_val = std::sqrt(yIn[3]*yIn[3] + yIn[4]*yIn[4] + yIn[5]*yIn[5]) ;
  G4double  inv_momentum = 1.0 / momentum_val ;
  G4double  yDir[3];
  // G4double  h_div_momentum = 1.0 / momentum_val ;

  for( G4int i = 0; i < 3; i++ ) {
    yDir[i]   = inv_momentum * yIn[i+3];
    yLinear[i]   = yIn[i] + h * yDir[i];
    // yLinear[i]   = yIn[i] + h_div_momentum * yIn[i+3];
    yLinear[i+3] = yIn[i+3];
  }
}

inline void
G4MagHelicalStepper::MagFieldEvaluate(const G4double y[],
                                      G4ThreeVector& Bfield )   
{
  G4double B[3];
  GetEquationOfMotion()->  GetFieldValue(y, B);
  Bfield= G4ThreeVector( B[0], B[1], B[2] );
}

inline G4double
G4MagHelicalStepper::GetInverseCurve(const G4double Momentum,
                                      const G4double Bmag)   
{
  
  G4double  inv_momentum = 1.0 / Momentum ;
  G4double particleCharge = fPtrMagEqOfMot->FCof() / (eplus*c_light); 
  G4double fCoefficient = -fUnitConstant  * particleCharge*inv_momentum;
 
  return  fCoefficient*Bmag;
}
inline void G4MagHelicalStepper:: SetAngCurve(const G4double Ang)
{                                                
fAngCurve=Ang; 
    
}

inline G4double G4MagHelicalStepper:: GetAngCurve() const 
{
return fAngCurve;  

}

inline void G4MagHelicalStepper:: SetCurve(const G4double Curve)
{
 frCurve=Curve;  
}

inline G4double G4MagHelicalStepper:: GetCurve() const 
{
return frCurve;  

}

inline void G4MagHelicalStepper:: SetRadHelix(const G4double Rad)
{
 frHelix=Rad;  
}

inline G4double G4MagHelicalStepper:: GetRadHelix() const 
{
return frHelix;  

}