defaultRKPropagator.h

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#ifndef RKPropagatorDefault_H
#define RKPropagatorDefault_H


#include "TrackPropagation/RungeKutta/interface/RKPropagatorInS.h"
#include "MagneticField/VolumeGeometry/interface/MagneticFieldProvider.h"


namespace defaultRKPropagator {

  using RKPropagator = RKPropagatorInS;

  // not clear why we need all this
  class TrivialFieldProvider final : public MagneticFieldProvider<float> {
  public:
    
    TrivialFieldProvider (const MagneticField* field) : theField(field) {}
    
    LocalVectorType valueInTesla( const LocalPointType& lp) const override {
      // NOTE: the following transformation only works for the central volume
      // where global and local coordinates are numerically equal !
      GlobalPoint gp(lp.basicVector());
      return LocalVectorType(theField->inTesla(gp).basicVector());
    }
    
  private:  
    const MagneticField* theField;
  };
  
  class RKMagVolume final : public MagVolume {
  public:
    RKMagVolume( const PositionType& pos, const RotationType& rot, 
         DDSolidShape shape, const MagneticFieldProvider<float> * mfp) :
      MagVolume( pos, rot, shape, mfp) {}
    
    virtual bool inside( const GlobalPoint& gp, double tolerance=0.) const {return true;}
    
    virtual const std::vector<VolumeSide>& faces() const {return theFaces;}
    
  private:
    std::vector<VolumeSide> theFaces;
  };
  
  struct Product {
    explicit Product(const MagneticField* field,PropagationDirection dir = alongMomentum, double tolerance = 5.e-5) : 
      mpf(field), 
      volume(MagVolume::PositionType(0,0,0), MagVolume::RotationType(),ddshapeless, &mpf),
      propagator(volume, dir, tolerance){}
    TrivialFieldProvider mpf;
    RKMagVolume volume;
    RKPropagator propagator;
  };
  
}

#endif // RKPropagatorDefault