AOD: Add TPC time0 option B (#13131)

f3sch · Benedikt Volkel · commit 82b4f7bfb3fd · 2024-05-23T20:40:39.000+02:00
* AOD: Add TPC time0 option B Signed-off-by: Felix Schlepper <felix.schlepper@cern.ch> * AOD: skip call to truncateFloat if tpc-only track Signed-off-by: Felix Schlepper <felix.schlepper@cern.ch> * AOD: store t0 wrt to BC of assoc. collision Signed-off-by: Felix Schlepper <felix.schlepper@cern.ch> * AOD: Also store used bcOfTimeRef Signed-off-by: Felix Schlepper <felix.schlepper@cern.ch> --------- Signed-off-by: Felix Schlepper <felix.schlepper@cern.ch> (cherry picked from commit 08d9479)
diff --git a/Detectors/AOD/include/AODProducerWorkflow/AODProducerWorkflowSpec.h b/Detectors/AOD/include/AODProducerWorkflow/AODProducerWorkflowSpec.h
@@ -389,6 +389,7 @@ class AODProducerWorkflowDPL : public Task
     float trackTimeRes = -999.f;
     int diffBCRef = 0; // offset of time reference BC from the start of the orbit
     int bcSlice[2] = {-1, -1};
+    bool isTPConly = false; // not to be written out
   };
 
   struct TrackQA {
diff --git a/Detectors/AOD/src/AODProducerWorkflowSpec.cxx b/Detectors/AOD/src/AODProducerWorkflowSpec.cxx
@@ -321,6 +321,13 @@ void AODProducerWorkflowDPL::addToTracksTable(TracksCursorType& tracksCursor, Tr
 template <typename TracksExtraCursorType>
 void AODProducerWorkflowDPL::addToTracksExtraTable(TracksExtraCursorType& tracksExtraCursor, TrackExtraInfo& extraInfoHolder)
 {
+  // In case of TPC-only tracks, do not truncate the time error since we encapsulate there a special encoding of
+  // the deltaFwd/Bwd times
+  auto trackTimeRes = extraInfoHolder.trackTimeRes;
+  if (!extraInfoHolder.isTPConly) {
+    trackTimeRes = truncateFloatFraction(trackTimeRes, mTrackTimeError);
+  }
+
   // extra
   tracksExtraCursor(truncateFloatFraction(extraInfoHolder.tpcInnerParam, mTrack1Pt),
                     extraInfoHolder.flags,
@@ -341,7 +348,7 @@ void AODProducerWorkflowDPL::addToTracksExtraTable(TracksExtraCursorType& tracks
                     truncateFloatFraction(extraInfoHolder.trackEtaEMCAL, mTrackPosEMCAL),
                     truncateFloatFraction(extraInfoHolder.trackPhiEMCAL, mTrackPosEMCAL),
                     truncateFloatFraction(extraInfoHolder.trackTime, mTrackTime),
-                    truncateFloatFraction(extraInfoHolder.trackTimeRes, mTrackTimeError));
+                    trackTimeRes);
 }
 
 template <typename TracksQACursorType>
@@ -486,7 +493,7 @@ void AODProducerWorkflowDPL::fillTrackTablesPerCollision(int collisionID,
             }
           }
 
-          if (extraInfoHolder.trackTimeRes < 0.f) { // failed or rejected?
+          if (!extraInfoHolder.isTPConly && extraInfoHolder.trackTimeRes < 0.f) { // failed or rejected?
             LOG(warning) << "Barrel track " << trackIndex << " has no time set, rejection is not expected : time=" << extraInfoHolder.trackTime
                          << " timeErr=" << extraInfoHolder.trackTimeRes << " BCSlice: " << extraInfoHolder.bcSlice[0] << ":" << extraInfoHolder.bcSlice[1];
             continue;
@@ -2438,11 +2445,21 @@ AODProducerWorkflowDPL::TrackExtraInfo AODProducerWorkflowDPL::processBarrelTrac
     extraInfoHolder.tpcNClsFindableMinusFound = tpcOrig.getNClusters() - tpcClData.found;
     extraInfoHolder.tpcNClsFindableMinusCrossedRows = tpcOrig.getNClusters() - tpcClData.crossed;
     extraInfoHolder.tpcNClsShared = tpcClData.shared;
-    if (src == GIndex::TPC) {                                                                                // standalone TPC track should set its time from their timebins range
-      double terr = 0.5 * (tpcOrig.getDeltaTFwd() + tpcOrig.getDeltaTBwd()) * mTPCBinNS;                     // half-span of the interval
-      double t = (tpcOrig.getTime0() + 0.5 * (tpcOrig.getDeltaTFwd() - tpcOrig.getDeltaTBwd())) * mTPCBinNS; // central value
-      LOG(debug) << "TPC tracks t0:" << tpcOrig.getTime0() << " tbwd: " << tpcOrig.getDeltaTBwd() << " tfwd: " << tpcOrig.getDeltaTFwd() << " t: " << t << " te: " << terr;
-      setTrackTime(t, terr, false);
+    if (src == GIndex::TPC) { // standalone TPC track should set its time from their timebins range
+      if (needBCSlice) {
+        double t = (tpcOrig.getTime0() + 0.5 * (tpcOrig.getDeltaTFwd() - tpcOrig.getDeltaTBwd())) * mTPCBinNS; // central value
+        double terr = 0.5 * (tpcOrig.getDeltaTFwd() + tpcOrig.getDeltaTBwd()) * mTPCBinNS;
+        double err = mTimeMarginTrackTime + terr;
+        bcOfTimeRef = fillBCSlice(extraInfoHolder.bcSlice, t - err, t + err, bcsMap);
+      }
+      aod::track::extensions::TPCTimeErrEncoding p;
+      p.setDeltaTFwd(tpcOrig.getDeltaTFwd());
+      p.setDeltaTBwd(tpcOrig.getDeltaTBwd());
+      extraInfoHolder.trackTimeRes = p.getTimeErr();
+      extraInfoHolder.trackTime = float(tpcOrig.getTime0() * mTPCBinNS - bcOfTimeRef * o2::constants::lhc::LHCBunchSpacingNS);
+      extraInfoHolder.diffBCRef = int(bcOfTimeRef);
+      extraInfoHolder.isTPConly = true; // no truncation
+      extraInfoHolder.flags |= o2::aod::track::TrackTimeAsym;
     } else if (src == GIndex::ITSTPC) { // its-tpc matched tracks have gaussian time error and the time was not set above
       const auto& trITSTPC = data.getTPCITSTrack(trackIndex);
       auto ts = trITSTPC.getTimeMUS();
diff --git a/Framework/Core/include/Framework/AnalysisDataModel.h b/Framework/Core/include/Framework/AnalysisDataModel.h
@@ -306,6 +306,29 @@ DECLARE_SOA_DYNAMIC_COLUMN(ITSClsSizeInLayer, itsClsSizeInLayer, //! Size of the
                              return (itsClusterSizes >> (layer * 4)) & 0xf;
                            });
 
+namespace extensions
+{
+using TPCTimeErrEncoding = o2::aod::track::extensions::TPCTimeErrEncoding;
+DECLARE_SOA_DYNAMIC_COLUMN(TPCDeltaTFwd, tpcDeltaTFwd, //! Delta Forward of track time in TPC time bis
+                           [](float timeErr, uint32_t trackType) -> float {
+                             if (!(trackType & TrackFlags::TrackTimeAsym)) {
+                               return TPCTimeErrEncoding::invalidValue;
+                             }
+                             TPCTimeErrEncoding enc;
+                             enc.encoding.timeErr = timeErr;
+                             return enc.getDeltaTFwd();
+                           });
+
+DECLARE_SOA_DYNAMIC_COLUMN(TPCDeltaTBwd, tpcDeltaTBwd, //! Delta Backward of track time in TPC time bis
+                           [](float timeErr, uint32_t trackType) -> float {
+                             if (!(trackType & TrackFlags::TrackTimeAsym)) {
+                               return TPCTimeErrEncoding::invalidValue;
+                             }
+                             TPCTimeErrEncoding p;
+                             p.encoding.timeErr = timeErr;
+                             return p.getDeltaTBwd();
+                           });
+} // namespace extensions
 } // namespace v001
 
 DECLARE_SOA_DYNAMIC_COLUMN(HasITS, hasITS, //! Flag to check if track has a ITS match
@@ -477,8 +500,8 @@ DECLARE_SOA_TABLE_FULL(StoredTracksExtra_000, "TracksExtra", "AOD", "TRACKEXTRA"
 DECLARE_SOA_TABLE_FULL_VERSIONED(StoredTracksExtra_001, "TracksExtra", "AOD", "TRACKEXTRA", 1, // On disk version of TracksExtra, version 1
                                  track::TPCInnerParam, track::Flags, track::ITSClusterSizes,
                                  track::TPCNClsFindable, track::TPCNClsFindableMinusFound, track::TPCNClsFindableMinusCrossedRows,
-                                 track::TPCNClsShared, track::TRDPattern, track::ITSChi2NCl,
-                                 track::TPCChi2NCl, track::TRDChi2, track::TOFChi2,
+                                 track::TPCNClsShared, track::v001::extensions::TPCDeltaTFwd<track::TrackTimeRes, track::Flags>, track::v001::extensions::TPCDeltaTBwd<track::TrackTimeRes, track::Flags>,
+                                 track::TRDPattern, track::ITSChi2NCl, track::TPCChi2NCl, track::TRDChi2, track::TOFChi2,
                                  track::TPCSignal, track::TRDSignal, track::Length, track::TOFExpMom,
                                  track::PIDForTracking<track::Flags>,
                                  track::IsPVContributor<track::Flags>,
diff --git a/Framework/Core/include/Framework/DataTypes.h b/Framework/Core/include/Framework/DataTypes.h
@@ -11,7 +11,10 @@
 #ifndef O2_FRAMEWORK_DATATYPES_H_
 #define O2_FRAMEWORK_DATATYPES_H_
 
+#include "CommonConstants/LHCConstants.h"
+
 #include <cstdint>
+#include <limits>
 
 namespace o2::aod::collision
 {
@@ -34,10 +37,11 @@ enum TrackTypeEnum : uint8_t {
   Run2Track = 254,
   Run2Tracklet = 255
 };
-enum TrackFlags {
+enum TrackFlags : uint32_t {
   TrackTimeResIsRange = 0x1, // Gaussian or range
   PVContributor = 0x2,       // This track has contributed to the collision vertex fit
   OrphanTrack = 0x4,         // Track has no association with any collision vertex
+  TrackTimeAsym = 0x8,       // track with an asymmetric time range
   // NOTE Highest 4 (29..32) bits reserved for PID hypothesis
 };
 enum TrackFlagsRun2Enum {
@@ -62,6 +66,52 @@ enum TRDTrackPattern : uint8_t {
   HasNeighbor = 0x40,
   HasCrossing = 0x80,
 };
+namespace extensions
+{
+struct TPCTimeErrEncoding {
+  // TPC delta forward & backward packing
+  union TPCDeltaTime {
+    struct {
+      uint16_t timeForward;
+      uint16_t timeBackward;
+    } __attribute__((packed)) deltas;
+    float timeErr;
+  } encoding;
+  static_assert(sizeof(float) == 2 * sizeof(uint16_t));
+
+  float getTimeErr() const
+  {
+    return encoding.timeErr;
+  }
+
+  // Use all 16 bits of uint16_t to encode delta scale with max precision
+  // e.g., TPCTrack::mDeltaFwd * timeScaler
+  // max range for the time deltas is 0 - <512 (1<<9) TPC time bins
+  static constexpr float timeScaler{(1 << 16) / (1 << 9)};
+  // bogus value to max incorrect usae immedately obvious
+  static constexpr float invalidValue{std::numeric_limits<float>::min()};
+  // convert TPC time bins to ns
+  static constexpr float TPCBinNS = 8 * o2::constants::lhc::LHCBunchSpacingNS;
+
+  void setDeltaTFwd(float fwd)
+  {
+    encoding.deltas.timeForward = static_cast<uint16_t>(fwd * timeScaler);
+  }
+  void setDeltaTBwd(float bwd)
+  {
+    encoding.deltas.timeBackward = static_cast<uint16_t>(bwd * timeScaler);
+  }
+
+  float getDeltaTFwd() const
+  {
+    return static_cast<float>(encoding.deltas.timeForward) / timeScaler * TPCBinNS;
+  }
+  float getDeltaTBwd() const
+  {
+    return static_cast<float>(encoding.deltas.timeBackward) / timeScaler * TPCBinNS;
+  }
+};
+} // namespace extensions
 } // namespace o2::aod::track
 
 namespace o2::aod::fwdtrack
