ParticleFlowReco/interface/PFTrack.h

0001 #ifndef DataFormats_ParticleFlowReco_PFTrack_h
0002 #define DataFormats_ParticleFlowReco_PFTrack_h
0003
0004 #include "DataFormats/ParticleFlowReco/interface/PFTrajectoryPoint.h"
0005
0006 #include <iostream>
0007 #include <vector>
0008
0009 namespace reco {
0010
0011   /**\class PFTrack
0012      \brief  Base class for particle flow input reconstructed tracks
0013      and simulated particles.
0014
0015      A PFTrack contains a vector of PFTrajectoryPoint objects.
0016      These points are stored in a vector to benefit from the
0017      random access. One must take care of storing the points in
0018      the right order, and it might even be necessary to insert dummy points.
0019
0020      For a PFRecTrack, the ordering of the points is the following:
0021
0022      - point 1: Closest approach
0023
0024      - point 2: Beam Pipe
0025
0026      - point 3 to n: Trajectory measurements (from the tracker layers)
0027
0028      - point n+1: Preshower Layer 1, or dummy point if
0029      not in the preshower zone
0030
0031      - point n+2: Preshower Layer 2, or dummy point if
0032      not in the preshower zone
0033
0034      - point n+3: ECAL Entrance
0035
0036      - point n+4: ECAL expected position of the shower maximum,
0037      assuming the track is an electron track.
0038
0039      - point n+5: HCAL Entrance
0040
0041      For a PFSimParticle, the ordering of the points is the following.
0042
0043      - If the particle decays before ECAL:
0044      - point 1: start point
0045      - point 2: end point
0046
0047      - If the particle does not decay before ECAL:
0048      - point 1: start point
0049      - point 2: PS1 or dummy
0050      - point 3: PS2 or dummy
0051      - point 4: ECAL entrance
0052      - point 5: HCAL entrance
0053
0054
0055      \todo Note that some points are missing, and should be added: shower max,
0056      intersection with the tracker layers maybe.
0057
0058      PFRecTracks and PFSimParticles are created in the PFTrackProducer module.
0059      \todo   Make this class abstract ?
0060      \author Renaud Bruneliere
0061      \date   July 2006
0062   */
0063   class PFTrack {
0064   public:
0065     PFTrack();
0066
0067     PFTrack(double charge);
0068
0069     PFTrack(const PFTrack& other);
0070
0071     PFTrack& operator=(const PFTrack& other) = default;
0072
0073     /// add a trajectory measurement
0074     /// \todo throw an exception if the number of points is too large
0075     void addPoint(const reco::PFTrajectoryPoint& trajPt);
0076
0077     /// set a trajectory point
0078     void setPoint(unsigned int index, const reco::PFTrajectoryPoint& measurement) {
0079       trajectoryPoints_[index] = measurement;
0080     }
0081
0082     /// \return electric charge
0083     double charge() const { return charge_; }
0084
0085     /// \return number of trajectory points
0086     unsigned int nTrajectoryPoints() const { return trajectoryPoints_.size(); }
0087
0088     /// \return number of trajectory measurements in tracker
0089     unsigned int nTrajectoryMeasurements() const {
0090       return (indexOutermost_ ? indexOutermost_ - indexInnermost_ + 1 : 0);
0091     }
0092
0093     /// \return vector of trajectory points
0094     const std::vector<reco::PFTrajectoryPoint>& trajectoryPoints() const { return trajectoryPoints_; }
0095
0096     /// \return a trajectory point
0097     const reco::PFTrajectoryPoint& trajectoryPoint(unsigned index) const { return trajectoryPoints_[index]; }
0098
0099     /// \return an extrapolated point
0100     /// \todo throw an exception in case of invalid point.
0101     const reco::PFTrajectoryPoint& extrapolatedPoint(unsigned layerid) const;
0102
0103     /// iterator on innermost tracker measurement
0104     std::vector<reco::PFTrajectoryPoint>::const_iterator innermostMeasurement() const {
0105       return trajectoryPoints_.begin() + indexInnermost_;
0106     }
0107
0108     /// iterator on outermost tracker measurement
0109     std::vector<reco::PFTrajectoryPoint>::const_iterator outermostMeasurement() const {
0110       return trajectoryPoints_.begin() + indexOutermost_;
0111     }
0112
0113   protected:
0114     /// maximal number of tracking layers
0115     static const unsigned int nMaxTrackingLayers_;
0116
0117     /// charge
0118     double charge_;
0119
0120     /// vector of trajectory points
0121     std::vector<reco::PFTrajectoryPoint> trajectoryPoints_;
0122
0123     /// index innermost tracker measurement
0124     unsigned int indexInnermost_;
0125
0126     /// index outermost tracker measurement
0127     unsigned int indexOutermost_;
0128   };
0129   std::ostream& operator<<(std::ostream& out, const PFTrack& track);
0130
0131 }  // namespace reco
0132
0133 #endif