KalmanVertexFit/src/SingleTrackVertexConstraint.cc

0001 #include "RecoVertex/KalmanVertexFit/interface/SingleTrackVertexConstraint.h"
0002 #include "DataFormats/GeometryCommonDetAlgo/interface/GlobalError.h"
0003 #include "FWCore/MessageLogger/interface/MessageLogger.h"
0004 #include "MagneticField/Engine/interface/MagneticField.h"
0005
0006 #include <algorithm>
0007 using namespace std;
0008 using namespace reco;
0009
0010 namespace {
0011   // FIXME
0012   // hard-coded tracker bounds
0013   // workaround while waiting for Geometry service
0014   const float TrackerBoundsRadius = 112;
0015   const float TrackerBoundsHalfLength = 273.5;
0016   bool insideTrackerBounds(const GlobalPoint& point) {
0017     return ((point.transverse() < TrackerBoundsRadius) && (abs(point.z()) < TrackerBoundsHalfLength));
0018   }
0019 }  // namespace
0020
0021 SingleTrackVertexConstraint::BTFtuple SingleTrackVertexConstraint::constrain(const TransientTrack& track,
0022                                                                              const GlobalPoint& priorPos,
0023                                                                              const GlobalError& priorError) const {
0024   VertexState priorVertexState(priorPos, priorError);
0025   return constrain(track, priorVertexState);
0026 }
0027
0028 SingleTrackVertexConstraint::BTFtuple SingleTrackVertexConstraint::constrain(const TransientTrack& track,
0029                                                                              const VertexState priorVertexState) const {
0030   // Linearize tracks
0031
0032   typedef CachingVertex<5>::RefCountedVertexTrack RefCountedVertexTrack;
0033   typedef VertexTrack<5>::RefCountedLinearizedTrackState RefCountedLinearizedTrackState;
0034
0035   double field = track.field()->inInverseGeV(track.impactPointState().globalPosition()).z();
0036   int nominalBfield = track.field()->nominalValue();
0037   if ((fabs(field) < 1e-4) && (fabs(nominalBfield) != 0)) {  //protection for the case where the magnet is off
0038     LogDebug("RecoVertex/SingleTrackVertexConstraint")
0039         << "Initial state is very far, field is close to zero (<1e-4): " << field << "\n";
0040     return BTFtuple(false, TransientTrack(), 0.);
0041   }
0042
0043   RefCountedLinearizedTrackState lTrData = theLTrackFactory.linearizedTrackState(priorVertexState.position(), track);
0044   RefCountedVertexTrack vertexTrack = theVTrackFactory.vertexTrack(lTrData, priorVertexState);
0045
0046   // Fit vertex
0047
0048   std::vector<RefCountedVertexTrack> initialTracks;
0049   CachingVertex<5> vertex(priorVertexState, priorVertexState, initialTracks, 0);
0050   vertex = vertexUpdator.add(vertex, vertexTrack);
0051   if (!vertex.isValid()) {
0052     return BTFtuple(false, TransientTrack(), 0.);
0053   } else if (doTrackerBoundCheck_ && (!insideTrackerBounds(vertex.position()))) {
0054     LogDebug("RecoVertex/SingleTrackVertexConstraint") << "Fitted position is out of tracker bounds.\n";
0055     return BTFtuple(false, TransientTrack(), 0.);
0056   }
0057
0058   RefCountedVertexTrack nTrack = theVertexTrackUpdator.update(vertex, vertexTrack);
0059   return BTFtuple(true, nTrack->refittedState()->transientTrack(), nTrack->smoothedChi2());
0060 }
0061
0062 SingleTrackVertexConstraint::BTFtuple SingleTrackVertexConstraint::constrain(const FreeTrajectoryState& fts,
0063                                                                              const GlobalPoint& priorPos,
0064                                                                              const GlobalError& priorError) const {
0065   return constrain(ttFactory.build(fts), priorPos, priorError);
0066 }
0067
0068 SingleTrackVertexConstraint::BTFtuple SingleTrackVertexConstraint::constrain(const TransientTrack& track,
0069                                                                              const reco::BeamSpot& spot) const {
0070   VertexState priorVertexState(spot);
0071   return constrain(track, priorVertexState);
0072 }
0073
0074 SingleTrackVertexConstraint::BTFtuple SingleTrackVertexConstraint::constrain(const FreeTrajectoryState& fts,
0075                                                                              const reco::BeamSpot& spot) const {
0076   VertexState priorVertexState(spot);
0077   return constrain(ttFactory.build(fts), priorVertexState);
0078 }