/data/refman/pasoursint/CMSSW_5_2_7_hltpatch1/src/TrackingTools/GeomPropagators/interface/StraightLinePropagator.h

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#ifndef TR_StraightLine_Propagator_H_
#define TR_StraightLine_Propagator_H_

#include "TrackingTools/GeomPropagators/interface/Propagator.h"
#include "DataFormats/TrajectorySeed/interface/PropagationDirection.h"
#include "TrackingTools/TrajectoryState/interface/TrajectoryStateOnSurface.h"

class MagneticField; 


class StraightLinePropagator : public Propagator {

private: 

  typedef FreeTrajectoryState FTS;
  typedef TrajectoryStateOnSurface TSOS;

public:

  StraightLinePropagator( const MagneticField* field,
                          PropagationDirection aDir = alongMomentum) : 
    Propagator(aDir), theField(field) {}

  ~StraightLinePropagator() {}

  virtual TSOS propagate(const FreeTrajectoryState& fts,
                         const Surface& surface) const {
    return Propagator::propagate(fts, surface);
  }
  
  virtual TSOS propagate(const FreeTrajectoryState& fts, 
                         const Plane& plane) const {
    return propagateWithPath(fts,plane).first;
  }

  virtual TSOS propagate(const FreeTrajectoryState& fts, 
                         const Cylinder& cylinder) const {
    return propagateWithPath(fts,cylinder).first;
  }
  
  std::pair<TSOS,double> propagateWithPath(const FreeTrajectoryState& fts, 
                                      const Surface& surface) const {
    return Propagator::propagateWithPath(fts,surface);
  }

  std::pair<TSOS,double> propagateWithPath(const FreeTrajectoryState& fts, 
                                      const Plane& surface) const;

  std::pair<TSOS,double> propagateWithPath(const FreeTrajectoryState& fts, 
                                      const Cylinder& surface) const;

  virtual StraightLinePropagator * clone() const {
    return new StraightLinePropagator(*this);
  }

 
  virtual const MagneticField* magneticField() const {return theField;}

private:

  const MagneticField* theField;

  // compute propagated state, with errors if needed
  TrajectoryStateOnSurface propagatedState(const FreeTrajectoryState& fts, 
                                           const Surface& surface, 
                                           const AlgebraicMatrix55& jacobian, 
                                           const GlobalPoint& x, 
                                           const GlobalVector& p) const;

  TrajectoryStateOnSurface propagatedState(const FreeTrajectoryState& fts, 
                                           const Surface& surface, 
                                           const AlgebraicMatrix55& jacobian, 
                                           const LocalPoint& x, 
                                           const LocalVector& p) const;


  // compute jacobian of transform
  AlgebraicMatrix55 jacobian(double& s) const;

  // compute propagated x and p and path s, return true when propagation is OK
  bool propagateParametersOnCylinder(const FreeTrajectoryState& fts, 
                                     const Cylinder& cylinder, 
                                     GlobalPoint& x, 
                                     GlobalVector& p, 
                                     double& s) const;

  // compute propagated x and p and path s, return true when propagation is OK
  bool propagateParametersOnPlane(const FreeTrajectoryState& fts, 
                                  const Plane& plane, 
                                  LocalPoint& x, 
                                  LocalVector& p, 
                                  double& s) const;

};

#endif