workstopgo

Signed-off-by: Felix Schlepper <felix.schlepper@cern.ch>

Detectors/GlobalTrackingWorkflow/src/TPCITSMatchingSpec.cxx

@@ -163,7 +163,7 @@ void TPCITSMatchingDPL::finaliseCCDB(ConcreteDataMatcher& matcher, void* obj)
     return;
   }
   if (matcher == ConcreteDataMatcher("ITS", "GEOMTGEO", 0)) {
-    LOG(info) << "ITS GeomtetryTGeo loaded from ccdb";
+    LOG(info) << "ITS GeometryTGeo loaded from ccdb";
     o2::its::GeometryTGeo::adopt((o2::its::GeometryTGeo*)obj);
     return;
   }

Detectors/ITSMFT/ITS/base/include/ITSBase/GeometryTGeo.h

@@ -333,9 +333,6 @@ class GeometryTGeo : public o2::itsmft::GeometryTGeo
   /// Sym name of the chip in the given layer/halfbarrel/stave/substave/module
   static const char* composeSymNameChip(int lr, int hba, int sta, int ssta, int mod, int chip, bool isITS3 = false);
 
-  // get tracking frame alpha for ITS3 clusters in global coordinates
-  static float getAlphaFromGlobalITS3(const o2::math_utils::Point3D<float>& gloXYZ);
-
   // create matrix for transformation from tracking frame to local one for ITS3
   const Mat3D getT2LMatrixITS3(int isn, float alpha);
 

Detectors/ITSMFT/ITS/base/src/GeometryTGeo.cxx

@@ -434,15 +434,6 @@ TGeoHMatrix* GeometryTGeo::extractMatrixSensor(int index) const
   return &matTmp;
 }
 
-//__________________________________________________________________________
-float GeometryTGeo::getAlphaFromGlobalITS3(const o2::math_utils::Point3D<float>& gloXYZ)
-{
-  // since ITS3 is cylindrical alpha = phi in global
-  auto alpha = std::atan2(gloXYZ.Y(), gloXYZ.X());
-  o2::math_utils::bringTo02Pi(alpha);
-  return alpha;
-}
-
 //__________________________________________________________________________
 const o2::math_utils::Transform3D GeometryTGeo::getT2LMatrixITS3(int isn, float alpha)
 {
@@ -893,11 +884,20 @@ void GeometryTGeo::extractSensorXAlpha(int isn, float& x, float& alp)
 
 #ifdef ENABLE_UPGRADES
   if (mIsLayerITS3[iLayer]) {
-    // in this case we need the line tangent to the circumference
-    double radius = 0.;
-    radius = o2::its3::constants::radii[iLayer];
-    locA[1] = radius;
-    locB[1] = radius;
+    // We need to calcualte the line tangent at the mid-point in the geometry
+    const auto radius = o2::its3::constants::radii[iLayer];
+    const auto phi1 = o2::its3::constants::tile::width / radius;
+    const auto phi2 = o2::its3::constants::pixelarray::width / radius + phi1;
+    const auto phi3 = (phi2 - phi1) / 2.; // mid-point in phi
+    const auto x = radius * std::cos(phi3);
+    const auto y = radius * std::sin(phi3);
+    // For the tangent we make the parametric line equation y = m * x - c
+    const auto m = x / y;
+    const auto c = y - m * x;
+    // Now we can given any x calulate points along this line, we pick points far away,
+    // the calculation of the normal should work then below.
+    locA[1] = m * locA[0] + c;
+    locB[1] = m * locB[0] + c;
   }
 #endif
 

Detectors/Upgrades/ITS3/reconstruction/src/IOUtils.cxx

@@ -98,14 +98,12 @@ int loadROFrameDataITS3(its::TimeFrame* tf,
       auto gloXYZ = geom->getMatrixL2G(sensorID) * locXYZ;
 
       // for cylindrical layers we have a different alpha for each cluster, for regular silicon detectors instead a single alpha for the whole sensor
-      float alpha = 0.;
+      float alpha = geom->getSensorRefAlpha(sensorID);
       o2::math_utils::Point3D<float> trkXYZ;
       if (isITS3) {
-        alpha = geom->getAlphaFromGlobalITS3(gloXYZ);
         // Inverse transformation to the local --> tracking
         trkXYZ = geom->getT2LMatrixITS3(sensorID, alpha) ^ locXYZ;
       } else {
-        alpha = geom->getSensorRefAlpha(sensorID);
         // Inverse transformation to the local --> tracking
         trkXYZ = geom->getMatrixT2L(sensorID) ^ locXYZ;
       }

Detectors/Upgrades/ITS3/workflow/src/TrackerSpec.cxx

@@ -342,7 +342,7 @@ void TrackerDPL::finaliseCCDB(ConcreteDataMatcher& matcher, void* obj)
     return;
   }
   if (matcher == ConcreteDataMatcher("ITS", "GEOMTGEO", 0)) {
-    LOG(info) << "IT3 GeomtetryTGeo loaded from ccdb";
+    LOG(info) << "IT3 GeometryTGeo loaded from ccdb";
     o2::its::GeometryTGeo::adopt((o2::its::GeometryTGeo*)obj);
     return;
   }