Add functionality to set the coordinates of PV.

Author: Maximilian Korwieser

Detectors/TPC/qc/include/TPCQC/Tracks.h

@@ -81,6 +81,14 @@ class Tracks
     mUseCutMaxAbsDCArOnHistos = useCutMaxAbsDCArOnHistos;
   }
 
+  // Set PV position
+  void setPVposition(const o2::math_utils::Point3D<float> meanVtxPoint3D)
+  {
+    mXpositionOfPV = meanVtxPoint3D.X();
+    mYpositionOfPV = meanVtxPoint3D.Y();
+    mZpositionOfPV = meanVtxPoint3D.Z();
+  }
+
   /// get ratios of 1D histograms
   std::unordered_map<std::string, std::unique_ptr<TH1>>& getMapHist() { return mMapHist; }
   const std::unordered_map<std::string, std::unique_ptr<TH1>>& getMapHist() const { return mMapHist; }
@@ -94,6 +102,9 @@ class Tracks
   bool mTurnOffHistosForAsync = false;    // Decide whether to turn off some histograms for async to reduce memory
   float mCutMaxAbsDCAr = 1.f;             // maximum DCAr
   bool mUseCutMaxAbsDCArOnHistos = false; // Decide whether to use the cut on maximum DCAr for the histograms
+  float mXpositionOfPV = 0.f;             // x-position of the PV
+  float mYpositionOfPV = 0.f;             // y-position of the PV
+  float mZpositionOfPV = 0.f;             // z-position of the PV
 
   std::unordered_map<std::string, std::unique_ptr<TH1>> mMapHist;
   std::vector<TH1F> mHist1D{};      ///< Initialize vector of 1D histograms

Detectors/TPC/qc/src/Tracks.cxx

@@ -180,7 +180,8 @@ bool Tracks::processTrack(const o2::tpc::TrackTPC& track)
       if (propagator->getMatLUT() && propagator->hasMagFieldSet()) {
         // ---| fill DCA histos |---
         o2::gpu::gpustd::array<float, 2> dca;
-        const o2::math_utils::Point3D<float> refPoint{0, 0, 0};
+        const o2::math_utils::Point3D<float> refPoint{mXpositionOfPV, mYpositionOfPV, mZpositionOfPV}; // inlcude option to fetch this information form the CCDB instead of assuming collision at nominal interaction point
+        // LOGP(error, "DeBugOutput: mXpositionOfPV({%.2f}), mYpositionOfPV({%.2f}),  mZpositionOfPV({%i})", mXpositionOfPV, mYpositionOfPV, mZpositionOfPV);
         o2::track::TrackPar propTrack(track);
         if (propagator->propagateToDCABxByBz(refPoint, propTrack, 2.f, o2::base::Propagator::MatCorrType::USEMatCorrLUT, &dca)) {
           const auto phi = o2::math_utils::to02PiGen(track.getPhi());