[Common] single-device TPC PID service for testing (#12277)

Co-authored-by: ALICE Builder <alibuild@users.noreply.github.com>

Author: ddobrigk

Common/Core/PID/TPCPIDResponse.h

@@ -74,12 +74,18 @@ class Response
   /// Gets the expected resolution of the track
   template <typename CollisionType, typename TrackType>
   float GetExpectedSigma(const CollisionType& collision, const TrackType& trk, const o2::track::PID::ID id) const;
+  /// Gets the expected resolution of the track with multTPC explicitly provided
+  template <typename TrackType>
+  float GetExpectedSigmaAtMultiplicity(const long multTPC, const TrackType& trk, const o2::track::PID::ID id) const;
   /// Gets the number of sigmas with respect the expected value
   template <typename CollisionType, typename TrackType>
   float GetNumberOfSigma(const CollisionType& collision, const TrackType& trk, const o2::track::PID::ID id) const;
   // Number of sigmas with respect to expected for MC, defining a tune-on-data signal value
   template <typename CollisionType, typename TrackType>
   float GetNumberOfSigmaMCTuned(const CollisionType& collision, const TrackType& trk, const o2::track::PID::ID id, float mcTunedTPCSignal) const;
+  // Number of sigmas with respect to expected for MC, defining a tune-on-data signal value, explicit multTPC
+  template <typename TrackType>
+  float GetNumberOfSigmaMCTunedAtMultiplicity(const long multTPC, const TrackType& trk, const o2::track::PID::ID id, float mcTunedTPCSignal) const;
   /// Gets the deviation to the expected signal
   template <typename TrackType>
   float GetSignalDelta(const TrackType& trk, const o2::track::PID::ID id) const;
@@ -116,6 +122,14 @@ inline float Response::GetExpectedSignal(const TrackType& track, const o2::track
 /// Gets the expected resolution of the measurement
 template <typename CollisionType, typename TrackType>
 inline float Response::GetExpectedSigma(const CollisionType& collision, const TrackType& track, const o2::track::PID::ID id) const
+{
+  // use multTPC (legacy behaviour) if multTPC not provided
+  return Response::GetExpectedSigmaAtMultiplicity(collision.multTPC(), track, id);
+}
+
+/// Gets the expected resolution of the measurement
+template <typename TrackType>
+inline float Response::GetExpectedSigmaAtMultiplicity(const long multTPC, const TrackType& track, const o2::track::PID::ID id) const
 {
   if (!track.hasTPC()) {
     return -999.f;
@@ -133,7 +147,7 @@ inline float Response::GetExpectedSigma(const CollisionType& collision, const Tr
     const double dEdx = o2::tpc::BetheBlochAleph(static_cast<float>(bg), mBetheBlochParams[0], mBetheBlochParams[1], mBetheBlochParams[2], mBetheBlochParams[3], mBetheBlochParams[4]) * std::pow(static_cast<float>(o2::track::pid_constants::sCharges[id]), mChargeFactor);
     const double relReso = GetRelativeResolutiondEdx(p, mass, o2::track::pid_constants::sCharges[id], mResolutionParams[3]);
 
-    const std::vector<double> values{1.f / dEdx, track.tgl(), std::sqrt(ncl), relReso, track.signed1Pt(), collision.multTPC() / mMultNormalization};
+    const std::vector<double> values{1.f / dEdx, track.tgl(), std::sqrt(ncl), relReso, track.signed1Pt(), multTPC / mMultNormalization};
 
     const float reso = sqrt(pow(mResolutionParams[0], 2) * values[0] + pow(mResolutionParams[1], 2) * (values[2] * mResolutionParams[5]) * pow(values[0] / sqrt(1 + pow(values[1], 2)), mResolutionParams[2]) + values[2] * pow(values[3], 2) + pow(mResolutionParams[4] * values[4], 2) + pow(values[5] * mResolutionParams[6], 2) + pow(values[5] * (values[0] / sqrt(1 + pow(values[1], 2))) * mResolutionParams[7], 2)) * dEdx * mMIP;
     reso >= 0.f ? resolution = reso : resolution = -999.f;
@@ -160,7 +174,13 @@ inline float Response::GetNumberOfSigma(const CollisionType& collision, const Tr
 template <typename CollisionType, typename TrackType>
 inline float Response::GetNumberOfSigmaMCTuned(const CollisionType& collision, const TrackType& trk, const o2::track::PID::ID id, float mcTunedTPCSignal) const
 {
-  if (GetExpectedSigma(collision, trk, id) < 0.) {
+  return Response::GetNumberOfSigmaMCTunedAtMultiplicity(collision.multTPC(), trk, id, mcTunedTPCSignal);
+}
+
+template <typename TrackType>
+inline float Response::GetNumberOfSigmaMCTunedAtMultiplicity(const long multTPC, const TrackType& trk, const o2::track::PID::ID id, float mcTunedTPCSignal) const
+{
+  if (GetExpectedSigmaAtMultiplicity(multTPC, trk, id) < 0.) {
     return -999.f;
   }
   if (GetExpectedSignal(trk, id) < 0.) {
@@ -169,7 +189,7 @@ inline float Response::GetNumberOfSigmaMCTuned(const CollisionType& collision, c
   if (!trk.hasTPC()) {
     return -999.f;
   }
-  return ((mcTunedTPCSignal - GetExpectedSignal(trk, id)) / GetExpectedSigma(collision, trk, id));
+  return ((mcTunedTPCSignal - GetExpectedSignal(trk, id)) / GetExpectedSigmaAtMultiplicity(multTPC, trk, id));
 }
 
 /// Gets the deviation between the actual signal and the expected signal

Common/TableProducer/PID/CMakeLists.txt

@@ -43,6 +43,11 @@ o2physics_add_dpl_workflow(pid-tof-full
 
 # TPC
 
+o2physics_add_dpl_workflow(pid-tpc-service
+                    SOURCES pidTPCService.cxx
+                    PUBLIC_LINK_LIBRARIES O2Physics::AnalysisCore O2Physics::MLCore O2Physics::AnalysisCCDB
+                    COMPONENT_NAME Analysis)
+
 o2physics_add_dpl_workflow(pid-tpc-base
                     SOURCES pidTPCBase.cxx
                     PUBLIC_LINK_LIBRARIES O2Physics::AnalysisCore O2Physics::AnalysisCCDB

Common/TableProducer/PID/pidTPC.cxx

@@ -447,6 +447,11 @@ struct tpcPid {
     }
 
     float nSigma = -999.f;
+    int multTPC = 0;
+    if (trk.has_collision()) {
+      auto collision = collisions.rawIteratorAt(trk.collisionId());
+      multTPC = collision.multTPC();
+    }
     float bg = trk.tpcInnerParam() / o2::track::pid_constants::sMasses[pid]; // estimated beta-gamma for network cutoff
     if (useNetworkCorrection && speciesNetworkFlags[pid] && trk.has_collision() && bg > networkBetaGammaCutoff) {
 
@@ -469,7 +474,7 @@ struct tpcPid {
         LOGF(fatal, "Network output-dimensions incompatible!");
       }
     } else {
-      nSigma = response->GetNumberOfSigmaMCTuned(collisions.iteratorAt(trk.collisionId()), trk, pid, tpcSignal);
+      nSigma = response->GetNumberOfSigmaMCTunedAtMultiplicity(multTPC, trk, pid, tpcSignal);
     }
     if (flagFull)
       tableFull(expSigma, nSigma);