From 7ad69b88fd208c42b56b7552ad4b9509849b6bb6 Mon Sep 17 00:00:00 2001
From: Oleksii Lubynets <O.Lubynets@gsi.de>
Date: Fri, 6 Nov 2026 23:20:49 +0100
Subject: [PATCH 1/2] seed rnd with timestamp

---
 Common/Tools/PID/pidTPCModule.h                |  6 +++++-
 DPG/Tasks/TPC/tpcSkimsTableCreator.cxx         | 16 ++++++++++++++--
 DPG/Tasks/TPC/treeCreatorPidTpcDiagnostics.cxx | 10 ++++++++++
 3 files changed, 29 insertions(+), 3 deletions(-)

diff --git a/Common/Tools/PID/pidTPCModule.h b/Common/Tools/PID/pidTPCModule.h
index 802d17a9b06..44234ed5dfa 100644
--- a/Common/Tools/PID/pidTPCModule.h
+++ b/Common/Tools/PID/pidTPCModule.h
@@ -723,7 +723,11 @@ class pidTPCModule
     }
     auto trackiterator = tracks.begin();
     if constexpr (requires { trackiterator.mcParticleId(); }) {
-      gRandom->SetSeed(0); // Ensure unique seed from UUID for each process call
+      if (bcs.size() != 0) {
+        const auto timestamp = bcs.begin().timestamp();
+        LOG(info) << "gRandom is seeded with timestamp of the 0-th bunch crossing (" << timestamp << ")";
+        gRandom->SetSeed(timestamp);
+      }
     }
 
     // preparatory step: we need the multiplicities for each collision
diff --git a/DPG/Tasks/TPC/tpcSkimsTableCreator.cxx b/DPG/Tasks/TPC/tpcSkimsTableCreator.cxx
index 3aaa024874e..b9488a81ece 100644
--- a/DPG/Tasks/TPC/tpcSkimsTableCreator.cxx
+++ b/DPG/Tasks/TPC/tpcSkimsTableCreator.cxx
@@ -166,7 +166,7 @@ struct TreeWriterTpcV0 {
 
   o2::aod::rctsel::RCTFlagsChecker rctChecker{};
 
-  TRandom3* fRndm = new TRandom3(0);
+  TRandom3* fRndm = new TRandom3();
 
   using Trks = soa::Join<aod::Tracks, aod::V0Bits, aod::TracksExtra, aod::pidTPCFullEl, aod::pidTPCFullPi, aod::pidTPCFullKa, aod::pidTPCFullPr, aod::pidTOFFullEl, aod::pidTOFFullPi, aod::pidTOFFullKa, aod::pidTOFFullPr, aod::TrackSelection>;
   using TrksWithDEdxCorrection = soa::Join<Trks, aod::DEdxsCorrected>;
@@ -420,6 +420,12 @@ struct TreeWriterTpcV0 {
   template <bool IsCorrectedDeDx, int ModeId, typename TrksType, typename BCType, typename TrkQAType>
   void runV0(Colls const& collisions, TrksType const& myTracks, V0sWithID const& myV0s, CascsWithID const& myCascs, TrkQAType const& tracksQA)
   {
+    if (collisions.size() != 0) {
+      const auto timestamp = collisions.begin().bc_as<BCType>().timestamp();
+      LOG(info) << "fRndm is seeded with timestamp of the 0-th bunch crossing (" << timestamp << ")";
+      fRndm->SetSeed(timestamp);
+    }
+
     constexpr bool IsWithTrackQa = ModeId != ModeStandard;
 
     std::vector<int64_t> labelTrack2TrackQA;
@@ -714,7 +720,7 @@ struct TreeWriterTpcTof {
 
   o2::aod::rctsel::RCTFlagsChecker rctChecker{};
 
-  TRandom3* fRndm = new TRandom3(0);
+  TRandom3* fRndm = new TRandom3();
 
   using Trks = soa::Join<aod::Tracks, aod::TracksExtra,
                          aod::pidTPCFullEl, aod::pidTPCFullPi, aod::pidTPCFullKa,
@@ -850,6 +856,12 @@ struct TreeWriterTpcTof {
   template <bool IsCorrectedDeDx, int ModeId, typename TrksType, typename BCType, typename TrkQAType, typename TMOType>
   void runTof(Colls const& collisions, TrksType const& myTracks, TrkQAType const& tracksQA, Preslice<TrksType> const& perCollisionTracksType, TMOType const& trackMeanOccs)
   {
+    if (collisions.size() != 0) {
+      const auto timestamp = collisions.begin().bc_as<BCType>().timestamp();
+      LOG(info) << "fRndm is seeded with timestamp of the 0-th bunch crossing (" << timestamp << ")";
+      fRndm->SetSeed(timestamp);
+    }
+
     constexpr bool IsWithTrackQa = ModeId != ModeStandard;
 
     std::vector<int64_t> labelTrack2TrackQA;
diff --git a/DPG/Tasks/TPC/treeCreatorPidTpcDiagnostics.cxx b/DPG/Tasks/TPC/treeCreatorPidTpcDiagnostics.cxx
index 8822995d239..8b20cb6889a 100644
--- a/DPG/Tasks/TPC/treeCreatorPidTpcDiagnostics.cxx
+++ b/DPG/Tasks/TPC/treeCreatorPidTpcDiagnostics.cxx
@@ -293,6 +293,16 @@ struct TreeCreatorPidTpcDiagnostics {
     }
   }
 
+  void process(const aod::Collisions& collisions,
+               const aod::BCsWithTimestamps&)
+  {
+    if (collisions.size() != 0) {
+      const auto timestamp = collisions.begin().bc_as<aod::BCsWithTimestamps>().timestamp();
+      LOG(info) << "mRnd is seeded with timestamp of the 0-th bunch crossing (" << timestamp << ")";
+      mRnd.SetSeed(timestamp);
+    }
+  }
+
 #define MAKE_PROCESS_FUNCTIONS(ParticleNameShort, ParticleNameLong, Unused)                                                                                         \
   void process##ParticleNameLong(CollisionsExtra const& collisions,                                                                                                 \
                                  soa::Join<TrackCandidates, aod::pidTPC##ParticleNameShort> const& tracks,                                                          \

From d48785fffef0da1b44036b9637c0b1d13db25ab0 Mon Sep 17 00:00:00 2001
From: Oleksii Lubynets <O.Lubynets@gsi.de>
Date: Fri, 6 Nov 2026 23:43:54 +0100
Subject: [PATCH 2/2] do not leave uninitialized variables

---
 DPG/Tasks/TPC/tpcSkimsTableCreator.cxx | 28 +++++++++++++-------------
 1 file changed, 14 insertions(+), 14 deletions(-)

diff --git a/DPG/Tasks/TPC/tpcSkimsTableCreator.cxx b/DPG/Tasks/TPC/tpcSkimsTableCreator.cxx
index b9488a81ece..ec4c98f2d6d 100644
--- a/DPG/Tasks/TPC/tpcSkimsTableCreator.cxx
+++ b/DPG/Tasks/TPC/tpcSkimsTableCreator.cxx
@@ -698,20 +698,20 @@ struct TreeWriterTpcTof {
   HistogramRegistry registry{"registry", {}};
 
   struct TofTrack {
-    bool isApplyHardCutOnly;
-    double maxMomHardCutOnly;
-    double maxMomTPCOnly;
-    double tpcNSigma;
-    double nSigmaTPCOnly;
-    double downsamplingTsalis;
-    double mass;
-    double tofNSigma;
-    double itsNSigma;
-    double tpcExpSignal;
-    o2::track::PID::ID pid;
-    double dwnSmplFactor;
-    double nSigmaTofTpctof;
-    double nSigmaTpcTpctof;
+    bool isApplyHardCutOnly{false};
+    double maxMomHardCutOnly{UndefValueDouble};
+    double maxMomTPCOnly{UndefValueDouble};
+    double tpcNSigma{UndefValueDouble};
+    double nSigmaTPCOnly{UndefValueDouble};
+    double downsamplingTsalis{UndefValueDouble};
+    double mass{UndefValueDouble};
+    double tofNSigma{UndefValueDouble};
+    double itsNSigma{UndefValueDouble};
+    double tpcExpSignal{UndefValueDouble};
+    o2::track::PID::ID pid{0};
+    double dwnSmplFactor{UndefValueDouble};
+    double nSigmaTofTpctof{UndefValueDouble};
+    double nSigmaTpcTpctof{UndefValueDouble};
   };
 
   Service<o2::ccdb::BasicCCDBManager> ccdb{};