FastHelix.h

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#ifndef TR_FastHelix_H_
#define TR_FastHelix_H_

#include "DataFormats/GeometryVector/interface/GlobalPoint.h"
#include "TrackingTools/TrajectoryState/interface/FreeTrajectoryState.h"
#include "RecoTracker/TkSeedGenerator/interface/FastCircle.h"
#include "FWCore/Framework/interface/EventSetup.h"
#include "FWCore/Framework/interface/ESHandle.h"
#include "MagneticField/Engine/interface/MagneticField.h"
#include "MagneticField/Records/interface/IdealMagneticFieldRecord.h"

class FastHelix {

private:
  
  typedef FreeTrajectoryState FTS;

public:


  //Original constructor (no basis vertex)
   FastHelix(const GlobalPoint& outerHit,
        const GlobalPoint& middleHit,
        const GlobalPoint& aVertex,
        const edm::EventSetup& iSetup) : theOuterHit(outerHit),
                         theMiddleHit(middleHit),
                         theVertex(aVertex),
                         theCircle(outerHit,
                               middleHit,
                               aVertex) {
          iSetup.get<IdealMagneticFieldRecord>().get(pSetup);
          tesla0=0.1*double(pSetup->nominalValue());
          maxRho = maxPt/(0.01 * 0.3*tesla0);
          useBasisVertex = false;
        }

  //New constructor (with basis vertex)
  FastHelix(const GlobalPoint& outerHit,
        const GlobalPoint& middleHit,
        const GlobalPoint& aVertex,
        const edm::EventSetup& iSetup,
        const GlobalPoint& bVertex) : theOuterHit(outerHit),
                          theMiddleHit(middleHit),
                          theVertex(aVertex),
                          basisVertex(bVertex),
                          theCircle(outerHit,
                                middleHit,
                            aVertex) {
          iSetup.get<IdealMagneticFieldRecord>().get(pSetup);
          tesla0=0.1*double(pSetup->nominalValue());
          maxRho = maxPt/(0.01 * 0.3*tesla0);
          useBasisVertex = true;
        }

  ~FastHelix() {}
  
  bool isValid() const {return theCircle.isValid();}

  FTS stateAtVertex() const;

  FTS helixStateAtVertex() const;

  FTS straightLineStateAtVertex() const;

  const FastCircle & circle() const { return theCircle; }

private:

  static constexpr double maxPt = 10000; // 10Tev

  GlobalPoint theOuterHit;
  GlobalPoint theMiddleHit;
  GlobalPoint theVertex;
  GlobalPoint basisVertex;
  FastCircle theCircle;
  edm::ESHandle<MagneticField> pSetup;
  double tesla0;
  double maxRho;
  bool useBasisVertex;
};

#endif //TR_FastHelix_H_