From 364b551f1dc935ccb5fa88566a6e6af842602de6 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Nicol=C3=B2=20Jacazio?= <nicolo.jacazio@cern.ch>
Date: Mon, 23 Aug 2021 12:29:28 +0200
Subject: [PATCH 1/2] Fix primary selection for QA

---
 Tasks/PWGPP/qaEventTrack.cxx | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/Tasks/PWGPP/qaEventTrack.cxx b/Tasks/PWGPP/qaEventTrack.cxx
index e904ae38a8c..f7876705f04 100644
--- a/Tasks/PWGPP/qaEventTrack.cxx
+++ b/Tasks/PWGPP/qaEventTrack.cxx
@@ -203,8 +203,8 @@ struct QaTrackingKine {
     }
   }
 
-  void process(const o2::soa::Join<o2::aod::Tracks, o2::aod::TracksCov, o2::aod::McTrackLabels>& tracks,
-               const o2::aod::McParticles& mcParticles)
+  void process(const o2::aod::McParticles& mcParticles,
+               const o2::soa::Join<o2::aod::Tracks, o2::aod::TracksCov, o2::aod::McTrackLabels>& tracks)
   {
     for (const auto& t : tracks) {
       const auto particle = t.mcParticle();
@@ -375,9 +375,10 @@ struct QaTrackingResolution {
     histos.add("impactParameter/impactParameterErrorZVsPhi", commonTitle + ";" + phiRec + ";" + impZErr, kTH2D, {phiAxis, impactParZErrorAxis});
   }
 
-  void process(const o2::soa::Join<o2::aod::Collisions, o2::aod::McCollisionLabels>::iterator& collision,
+  void process(const o2::aod::McParticles& mcParticles,
+               const o2::soa::Join<o2::aod::Collisions, o2::aod::McCollisionLabels>::iterator& collision,
                const o2::soa::Join<o2::aod::Tracks, o2::aod::TracksCov, o2::aod::McTrackLabels>& tracks,
-               const o2::aod::McParticles& mcParticles, const o2::aod::McCollisions& mcCollisions)
+               const o2::aod::McCollisions& mcCollisions)
   {
     const VertexBase primaryVertex = getPrimaryVertex(collision);
     DCA dca;

From 3a13b2e33459711358b2a727d2565ecab2d66412 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Nicol=C3=B2=20Jacazio?= <nicolo.jacazio@cern.ch>
Date: Mon, 23 Aug 2021 17:52:00 +0200
Subject: [PATCH 2/2] Fix prim. vertex

---
 Tasks/PWGPP/qaEventTrack.cxx | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/Tasks/PWGPP/qaEventTrack.cxx b/Tasks/PWGPP/qaEventTrack.cxx
index f7876705f04..df849fae967 100644
--- a/Tasks/PWGPP/qaEventTrack.cxx
+++ b/Tasks/PWGPP/qaEventTrack.cxx
@@ -376,11 +376,10 @@ struct QaTrackingResolution {
   }
 
   void process(const o2::aod::McParticles& mcParticles,
-               const o2::soa::Join<o2::aod::Collisions, o2::aod::McCollisionLabels>::iterator& collision,
+               const o2::soa::Join<o2::aod::Collisions, o2::aod::McCollisionLabels>& collision,
                const o2::soa::Join<o2::aod::Tracks, o2::aod::TracksCov, o2::aod::McTrackLabels>& tracks,
                const o2::aod::McCollisions& mcCollisions)
   {
-    const VertexBase primaryVertex = getPrimaryVertex(collision);
     DCA dca;
     // FIXME: get this from CCDB
     constexpr float magneticField{5.0};      // in kG
@@ -416,7 +415,7 @@ struct QaTrackingResolution {
 
       histos.fill(HIST("phi/phiDiffRecGen"), track.phi() - particle.phi());
 
-      if (getTrackParCov(track).propagateToDCA(primaryVertex, magneticField, &dca, 100.)) { // Check that the propagation is successfull
+      if (getTrackParCov(track).propagateToDCA(getPrimaryVertex(track.collision()), magneticField, &dca, 100.)) { // Check that the propagation is successfull
         impactParameterRPhi = toMicrometers * dca.getY();
         impactParameterRPhiError = toMicrometers * sqrt(dca.getSigmaY2());
         impactParameterZ = toMicrometers * dca.getZ();