BDSIntegratorDipoleRodrigues.hh

/* 
Beam Delivery Simulation (BDSIM) Copyright (C) Royal Holloway, 
University of London 2001 - 2022.
 
This file is part of BDSIM.
 
BDSIM is free software: you can redistribute it and/or modify 
it under the terms of the GNU General Public License as published 
by the Free Software Foundation version 3 of the License.
 
BDSIM is distributed in the hope that it will be useful, but 
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.
 
You should have received a copy of the GNU General Public License
along with BDSIM.  If not, see <http://www.gnu.org/licenses/>.
*/
#ifndef BDSINTEGRATORDIPOLERODRIGUES_H
#define BDSINTEGRATORDIPOLERODRIGUES_H
 
#include "BDSIntegratorMag.hh"
 
#include "globals.hh"
#include "G4ThreeVector.hh"
 
#include <utility>
 
class G4Mag_EqRhs;
class BDSMagnetStrength;
 
class BDSIntegratorDipoleRodrigues: public BDSIntegratorMag
{
public:
  BDSIntegratorDipoleRodrigues(BDSMagnetStrength const* strength,
                               G4double                 brho,
                               G4Mag_EqRhs*             eqOfMIn);
    
  virtual ~BDSIntegratorDipoleRodrigues(){;}
 
  virtual void Stepper(const G4double yIn[],
                       const G4double dydx[],
                       const G4double h,
                       G4double       yOut[],
                       G4double       yErr[]);
  
protected:
  void AdvanceHelix(const G4double yIn[],
                    const G4double dydx[],
                    G4double       h,
                    G4double       yOut[],
                    G4double       yErr[]);
 
  G4double cOverGeV;
 
  const G4double angle;
 
  const G4double length;
 
  G4double bField;
 
  BDSMagnetStrength const* strength;
 
  std::pair<G4ThreeVector,G4ThreeVector> UpdatePandR(G4double rho,
                                                     G4double h,
                                                     G4ThreeVector localPos,
                                                     G4ThreeVector localMomUnit);
  
private:
  G4ThreeVector yInitial, yMidPoint, yFinal;
 
  const G4double minimumRadiusOfCurvature;
};
 
#endif