Introdue utility function to determine radius of innermost hit

key4hep · Jul 2, 2024 · 475ff4f · 475ff4f
1 parent 3e4d903
commit 475ff4f
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Showing 3 changed files with 17 additions and 9 deletions.
diff --git a/k4EDM4hep2LcioConv/include/k4EDM4hep2LcioConv/k4EDM4hep2LcioConv.h b/k4EDM4hep2LcioConv/include/k4EDM4hep2LcioConv/k4EDM4hep2LcioConv.h
@@ -430,6 +430,12 @@ convEvent(const podio::Frame& edmEvent, const podio::Frame& metadata = podio::Fr
   return convertEvent(edmEvent, metadata);
 }
 
+/**
+ * Get the 3D radius of the TrackState at the IP from the given track. This is
+ * used to set the radiusOfInnermostHit in the LCIO track during the conversion
+ */
+std::optional<double> getRadiusOfStateAtIP(const edm4hep::Track& track);
+
 } // namespace EDM4hep2LCIOConv
 
 #include "k4EDM4hep2LcioConv/k4EDM4hep2LcioConv.ipp"

diff --git a/k4EDM4hep2LcioConv/include/k4EDM4hep2LcioConv/k4EDM4hep2LcioConv.ipp b/k4EDM4hep2LcioConv/include/k4EDM4hep2LcioConv/k4EDM4hep2LcioConv.ipp
@@ -27,15 +27,7 @@ std::unique_ptr<lcio::LCCollectionVec> convertTracks(const edm4hep::TrackCollect
       lcio_tr->setNdf(edm_tr.getNdf());
       lcio_tr->setdEdx(edm_tr.getDEdx());
       lcio_tr->setdEdxError(edm_tr.getDEdxError());
-      double radius = std::numeric_limits<double>::max();
-      for (const auto& hit : edm_tr.getTrackerHits()) {
-        radius = std::min(radius, std::sqrt(hit.getPosition()[0] * hit.getPosition()[0] +
-                                            hit.getPosition()[1] * hit.getPosition()[1]));
-      }
-      if (radius == std::numeric_limits<double>::max()) {
-        radius = 0;
-      }
-      lcio_tr->setRadiusOfInnermostHit(radius);
+      lcio_tr->setRadiusOfInnermostHit(getRadiusOfStateAtIP(edm_tr).value_or(-1.0));
 
       // Loop over the hit Numbers in the track
       lcio_tr->subdetectorHitNumbers().resize(edm_tr.subdetectorHitNumbers_size());

diff --git a/k4EDM4hep2LcioConv/src/k4EDM4hep2LcioConv.cpp b/k4EDM4hep2LcioConv/src/k4EDM4hep2LcioConv.cpp
@@ -147,4 +147,14 @@ std::unique_ptr<lcio::LCEventImpl> convertEvent(const podio::Frame& edmEvent, co
   return lcioEvent;
 }
 
+std::optional<double> getRadiusOfStateAtIP(const edm4hep::Track& track) {
+  for (const auto& state : track.getTrackStates()) {
+    if (state.location == edm4hep::TrackState::AtIP) {
+      const auto refP = state.referencePoint;
+      return std::sqrt(refP.x * refP.x + refP.y * refP.y + refP.z * refP.z);
+    }
+  }
+  return std::nullopt;
+}
+
 } // namespace EDM4hep2LCIOConv