From f8b243202bcf3adf1ee430699ab39e44d0249ed1 Mon Sep 17 00:00:00 2001
From: Fabrizio Grosa <fabrizio.grosa@cern.ch>
Date: Fri, 26 Jun 2026 18:17:45 +0200
Subject: [PATCH] Fix seed initialisation of c-deuteron gun and status codes

---
 .../generator_pythia8_embed_charmnuclei.C       | 17 +++++++++++++----
 1 file changed, 13 insertions(+), 4 deletions(-)

diff --git a/MC/config/PWGHF/external/generator/generator_pythia8_embed_charmnuclei.C b/MC/config/PWGHF/external/generator/generator_pythia8_embed_charmnuclei.C
index 4e6f69ba0..94c9c0b80 100644
--- a/MC/config/PWGHF/external/generator/generator_pythia8_embed_charmnuclei.C
+++ b/MC/config/PWGHF/external/generator/generator_pythia8_embed_charmnuclei.C
@@ -22,7 +22,7 @@ class GeneratorPythia8HFEmbedCharmNuclei : public o2::eventgen::GeneratorPythia8
  public:
 
   /// constructor
-  GeneratorPythia8HFEmbedCharmNuclei(int pdgCode = 2010010020, float lifetime = 1.f, int nCharmNucleiPerEvent = 10, float yMin = -1.f, float yMax = 1.f, float ptMax = 25.f, bool trivialCoal = false, float coalMomentum = 0.2, float fracFromB = 0.f)
+  GeneratorPythia8HFEmbedCharmNuclei(int pdgCode = 2010010020, float lifetime = 1.f, int nCharmNucleiPerEvent = 10, float yMin = -1.f, float yMax = 1.f, float ptMax = 25.f, bool trivialCoal = false, float coalMomentum = 0.2, float fracFromB = 0.f, unsigned int seed = 0u)
   {
     nNumberOfCharmNucleiPerEvent = nCharmNucleiPerEvent;
     mRapidityMinCharmNuclei = yMin;
@@ -33,6 +33,7 @@ class GeneratorPythia8HFEmbedCharmNuclei : public o2::eventgen::GeneratorPythia8
     mFractionFromBeauty = fracFromB;
     mPdgCharmNucleus = pdgCode;
     mSign = 1;
+    mUsedSeed = seed;
     if (std::abs(mPdgCharmNucleus) == 2010010020) {
       mMassCharmNucleus = 3.226f;
     } else {
@@ -63,6 +64,9 @@ class GeneratorPythia8HFEmbedCharmNuclei : public o2::eventgen::GeneratorPythia8
       LOG(fatal) << "Failed to init \'GeneratorPythia8\': problems with configuration file " << cfg;
     }
 
+    mPythiaGun.readString("Random:setSeed = on");
+    mPythiaGun.readString("Random:seed = " + std::to_string(seed));
+
     if (!mPythiaGun.init()) {
       LOG(fatal) << "Failed to init \'GeneratorPythia8\': init returned with error";
     }
@@ -170,7 +174,8 @@ class GeneratorPythia8HFEmbedCharmNuclei : public o2::eventgen::GeneratorPythia8
         mPythiaGun.moreDecays();
         std::array<int, 2> dausToCoal = {-1, -1};
         std::vector<int> pdgShortLivedResos = {313, 2224, 102134};
-        std::map<int, int> statusResoDecay = {{313, 95}, {2224, 96}, {102134, 97}}; // do not use 94, it is used by default for no resonances
+        std::map<int, int> statusResoDecay = {{313, -85}, {2224, -86}, {102134, -87}}; // do not use 94, it is used by default for no resonances
+        std::map<int, int> statusResoDecayFromB = {{313, -95}, {2224, -96}, {102134, -97}}; // do not use 94, it is used by default for no resonances
         int whichReso{0};
         int idxCharmNucleus{-1};
         for (int iPart{0}; iPart<mPythiaGun.event.size(); ++iPart) {
@@ -245,7 +250,11 @@ class GeneratorPythia8HFEmbedCharmNuclei : public o2::eventgen::GeneratorPythia8
         // we try the coalescence here, if successful we copy particles in the pythia event and we move to the next charm nucleus
         isCoalSuccess = CoalescencePythia8(mPythiaGun.event, std::vector<unsigned int>{1000010020}, mTrivialCoal, mCoalMomentum, dausToCoal[0], dausToCoal[1], 10.);
         if (whichReso > 0) {
-          mPythiaGun.event[idxCharmNucleus].status(statusResoDecay[whichReso]);
+          if (isFromB) {
+            mPythiaGun.event[idxCharmNucleus].status(statusResoDecayFromB[whichReso]);
+          } else {
+            mPythiaGun.event[idxCharmNucleus].status(statusResoDecay[whichReso]);
+          }
         }
         if (isCoalSuccess) {
           restoreEnergyConservation(mPythiaGun.event, idxCharmNucleus);
@@ -332,8 +341,8 @@ private:
 ///___________________________________________________________
 FairGenerator *GenerateHFEmbedCDeuteron(float lifetime = 1.f, int nCharmNucleiPerEvent = 10, float yMin = -1.f, float yMax = 1.f, float ptMax = 25.f, bool trivialCoal = false, float coalMomentum = 0.2f, float fracFromB = 0.25f)
 {
-  auto myGen = new GeneratorPythia8HFEmbedCharmNuclei(2010010020, lifetime, nCharmNucleiPerEvent, yMin, yMax, ptMax, trivialCoal, coalMomentum, fracFromB);
   auto seed = (gRandom->TRandom::GetSeed() % 900000000);
+  auto myGen = new GeneratorPythia8HFEmbedCharmNuclei(2010010020, lifetime, nCharmNucleiPerEvent, yMin, yMax, ptMax, trivialCoal, coalMomentum, fracFromB, seed);
   myGen->readString("Random:setSeed on");
   myGen->readString("Random:seed " + std::to_string(seed));
   return myGen;