Remove superfluous seeding code for GeneratorPythia8 generators

This commit harmonizes the seeding procedure of generators based
on o2::eventgen::GeneratorPythia8, following a development done in O2
(AliceO2Group/AliceO2#13281)

In principle, o2::eventgen::GeneratorPythia8 now performs it's own
seeding within the Init function. This seeding makes sure
to integrate with the `--seed` command line option of our event generation
executable.

The commit:
* Removes seeding code in O2DPG when it would override the default
  behaviour from O2.

* Uses a new dedicated function `setInitialSeed` instead of manipulating
  Pythia8 with config strings (in situations in which the user
  targets seeding based on ALIEN_PROC_ID for instance).

* Ensures that event generation becomes more repeatable in situations
  when the same `--seed` is given to the event generation executable.
  This may help to debug crashes on the GRID etc.

MC/config/PWGDQ/external/generator/GeneratorBeautyToJpsi_EvtGen.C

@@ -32,15 +32,7 @@ FairGenerator*
     printf("PDG %d \n", std::stoi(spdg));
   }
   gen->SetForceDecay(kEvtBJpsiDiElectron);
-
-  // set random seed
-  gen->readString("Random:setSeed on");
-  uint random_seed;
-  unsigned long long int random_value = 0; 
-  ifstream urandom("/dev/urandom", ios::in|ios::binary);
-  urandom.read(reinterpret_cast<char*>(&random_value), sizeof(random_seed));
-  gen->readString(Form("Random:seed = %d", random_value % 900000001));
-
+
   // print debug
   // gen->PrintDebug();
 
@@ -70,13 +62,6 @@ FairGenerator*
     printf("PDG %d \n", std::stoi(spdg));
   }
   gen->SetForceDecay(kEvtBJpsiDiMuon);
-  // set random seed
-  gen->readString("Random:setSeed on");
-  uint random_seed;
-  unsigned long long int random_value = 0; 
-  ifstream urandom("/dev/urandom", ios::in|ios::binary);
-  urandom.read(reinterpret_cast<char*>(&random_value), sizeof(random_seed));
-  gen->readString(Form("Random:seed = %d", random_value % 900000001));
   // print debug
   // gen->PrintDebug();
 

MC/config/PWGDQ/external/generator/GeneratorBeautyToMu_EvtGen.C

@@ -32,13 +32,6 @@ GeneratorBeautyToMu_EvtGenFwdY(double rapidityMin = -4.3, double rapidityMax = -
   }
   if(forcedecay) gen->SetForceDecay(kEvtSemiMuonic);
   else gen->SetForceDecay(kEvtAll);
-  // set random seed
-  gen->readString("Random:setSeed on");
-  uint random_seed;
-  unsigned long long int random_value = 0; 
-  ifstream urandom("/dev/urandom", ios::in|ios::binary);
-  urandom.read(reinterpret_cast<char*>(&random_value), sizeof(random_seed));
-  gen->readString(Form("Random:seed = %d", random_value % 900000001));
   // print debug
   // gen->PrintDebug();
 

MC/config/PWGDQ/external/generator/GeneratorBeautyToPsiAndJpsi_EvtGen.C

@@ -32,15 +32,6 @@ FairGenerator*
     printf("PDG %d \n", std::stoi(spdg));
   }
   gen->SetForceDecay(kEvtBPsiAndJpsiDiElectron);
-
-  // set random seed
-  gen->readString("Random:setSeed on");
-  uint random_seed;
-  unsigned long long int random_value = 0; 
-  ifstream urandom("/dev/urandom", ios::in|ios::binary);
-  urandom.read(reinterpret_cast<char*>(&random_value), sizeof(random_seed));
-  gen->readString(Form("Random:seed = %d", random_value % 900000001));
-
   // print debug
   // gen->PrintDebug();
 
@@ -70,13 +61,6 @@ FairGenerator*
     printf("PDG %d \n", std::stoi(spdg));
   }
   gen->SetForceDecay(kEvtBPsiAndJpsiDiMuon);
-  // set random seed
-  gen->readString("Random:setSeed on");
-  uint random_seed;
-  unsigned long long int random_value = 0; 
-  ifstream urandom("/dev/urandom", ios::in|ios::binary);
-  urandom.read(reinterpret_cast<char*>(&random_value), sizeof(random_seed));
-  gen->readString(Form("Random:seed = %d", random_value % 900000001));
   // print debug
   // gen->PrintDebug();
 

MC/config/PWGDQ/external/generator/GeneratorBeautyToPsi_EvtGen.C

@@ -32,13 +32,6 @@ FairGenerator*
     printf("PDG %d \n", std::stoi(spdg));
   }
   gen->SetForceDecay(kEvtBPsiDiElectron);
-  // set random seed
-  gen->readString("Random:setSeed on");
-  uint random_seed;
-  unsigned long long int random_value = 0; 
-  ifstream urandom("/dev/urandom", ios::in|ios::binary);
-  urandom.read(reinterpret_cast<char*>(&random_value), sizeof(random_seed));
-  gen->readString(Form("Random:seed = %d", random_value % 900000001));
   // print debug
   // gen->PrintDebug();
 
@@ -68,13 +61,6 @@ FairGenerator*
     printf("PDG %d \n", std::stoi(spdg));
   }
   gen->SetForceDecay(kEvtBPsiDiMuon);
-  // set random seed
-  gen->readString("Random:setSeed on");
-  uint random_seed;
-  unsigned long long int random_value = 0; 
-  ifstream urandom("/dev/urandom", ios::in|ios::binary);
-  urandom.read(reinterpret_cast<char*>(&random_value), sizeof(random_seed));
-  gen->readString(Form("Random:seed = %d", random_value % 900000001));
   // print debug
   // gen->PrintDebug();
 

MC/config/PWGDQ/external/generator/GeneratorBplusToJpsiKaon_EvtGen.C

@@ -33,13 +33,6 @@ FairGenerator*
   gen->SetDecayTable(Form("%s/BPLUSTOKAONJPSITOELE.DEC", pathO2.Data()));
   // print debug
   // gen->PrintDebug();
-  // set random seed
-  gen->readString("Random:setSeed on");
-  uint random_seed;
-  unsigned long long int random_value = 0; 
-  ifstream urandom("/dev/urandom", ios::in|ios::binary);
-  urandom.read(reinterpret_cast<char*>(&random_value), sizeof(random_seed));
-  gen->readString(Form("Random:seed = %d", random_value % 900000001));
-
+
   return gen;
 }

MC/config/PWGDQ/external/generator/GeneratorCharmToMu_EvtGen.C

@@ -31,13 +31,6 @@ GeneratorCharmToMu_EvtGenFwdY(double rapidityMin = -4.3, double rapidityMax = -2
    printf("PDG %d \n",std::stoi(spdg));
   }
   gen->SetForceDecay(kEvtSemiMuonic);
-  // set random seed
-  gen->readString("Random:setSeed on");
-  uint random_seed;
-  unsigned long long int random_value = 0; 
-  ifstream urandom("/dev/urandom", ios::in|ios::binary);
-  urandom.read(reinterpret_cast<char*>(&random_value), sizeof(random_seed));
-  gen->readString(Form("Random:seed = %d", random_value % 900000001));
   // print debug
   // gen->PrintDebug();
 

MC/config/PWGDQ/external/generator/generator_pythia8_NonPromptSignals_gaptriggered_dq.C

@@ -64,7 +64,7 @@ public:
 
 protected:
 
-Bool_t generateEvent() override
+  Bool_t generateEvent() override
   {
      // reset  event
      bool genOk = false;
@@ -90,13 +90,15 @@ Bool_t generateEvent() override
     return true;
   }
 
-Bool_t Init() override
+  Bool_t Init() override
   {
-        if(mConfigMBdecays.Contains("cfg")) pythiaMBgen.readFile(mConfigMBdecays.Data());	
-	GeneratorPythia8::Init();
-       	pythiaMBgen.init();
-        return true;
-  } 
+    if(mConfigMBdecays.Contains("cfg")) {
+       pythiaMBgen.readFile(mConfigMBdecays.Data());
+    }
+	  GeneratorPythia8::Init();
+    pythiaMBgen.init();
+    return true;
+  }
 
   // search for q-qbar mother with at least one q in a selected rapidity window
   bool findHeavyQuarkPair(Pythia8::Event& event)
@@ -181,14 +183,6 @@ FairGenerator*
   }
   gen->SetForceDecay(kEvtBJpsiDiElectron);
 
-  // set random seed
-  gen->readString("Random:setSeed on");
-  uint random_seed;
-  unsigned long long int random_value = 0;
-  ifstream urandom("/dev/urandom", ios::in|ios::binary);
-  urandom.read(reinterpret_cast<char*>(&random_value), sizeof(random_seed));
-  gen->readString(Form("Random:seed = %d", random_value % 900000001));
-
   // print debug
   // gen->PrintDebug();
 
@@ -219,14 +213,6 @@ FairGenerator*
   }
   gen->SetForceDecay(kEvtBPsiAndJpsiDiElectron);
 
-  // set random seed
-  gen->readString("Random:setSeed on");
-  uint random_seed;
-  unsigned long long int random_value = 0;
-  ifstream urandom("/dev/urandom", ios::in|ios::binary);
-  urandom.read(reinterpret_cast<char*>(&random_value), sizeof(random_seed));
-  gen->readString(Form("Random:seed = %d", random_value % 900000001));
-
   // print debug
   // gen->PrintDebug();
 
@@ -261,15 +247,7 @@ FairGenerator*
   //gen->SetDecayTable(Form("%s/BPLUSTOKAONJPSITOELE.DEC", pathO2.Data()));
   gen->SetDecayTable(Form("%s/BPLUSTOKAONJPSITOELEALLMODES.DEC", pathO2.Data())); // decay table including decay modes for correlated background
   // print debug
-  // gen->PrintDebug();
-  // set random seed
-  gen->readString("Random:setSeed on");
-  uint random_seed;
-  unsigned long long int random_value = 0;
-  ifstream urandom("/dev/urandom", ios::in|ios::binary);
-  urandom.read(reinterpret_cast<char*>(&random_value), sizeof(random_seed));
-  gen->readString(Form("Random:seed = %d", random_value % 900000001));
-
+  // gen->PrintDebug();   
   return gen;
 }
 
@@ -298,14 +276,6 @@ FairGenerator*
   }
   gen->SetForceDecay(kEvtBJpsiDiMuon);
 
-  // set random seed
-  gen->readString("Random:setSeed on");
-  uint random_seed;
-  unsigned long long int random_value = 0;
-  ifstream urandom("/dev/urandom", ios::in|ios::binary);
-  urandom.read(reinterpret_cast<char*>(&random_value), sizeof(random_seed));
-  gen->readString(Form("Random:seed = %d", random_value % 900000001));
-
   // print debug
   // gen->PrintDebug();
 
@@ -337,17 +307,8 @@ FairGenerator*
   }
   gen->SetForceDecay(kEvtBPsiAndJpsiDiMuon);
 
-  // set random seed
-  gen->readString("Random:setSeed on");
-  uint random_seed;
-  unsigned long long int random_value = 0;
-  ifstream urandom("/dev/urandom", ios::in|ios::binary);
-  urandom.read(reinterpret_cast<char*>(&random_value), sizeof(random_seed));
-  gen->readString(Form("Random:seed = %d", random_value % 900000001));
-
   // print debug
   // gen->PrintDebug();
-
   return gen;
 }
 

MC/config/PWGEM/external/generator/GeneratorBeautyToEle_EvtGen.C

@@ -34,13 +34,6 @@ GeneratorBeautyToEle_EvtGen(double rapidityMin = -2., double rapidityMax = 2., b
   if(forcedecay) gen->SetForceDecay(kEvtSemiElectronic);
   else gen->SetForceDecay(kEvtAll);
    //}
-  // set random seed
-  gen->readString("Random:setSeed on");
-  uint random_seed;
-  unsigned long long int random_value = 0; 
-  ifstream urandom("/dev/urandom", ios::in|ios::binary);
-  urandom.read(reinterpret_cast<char*>(&random_value), sizeof(random_seed));
-  gen->readString(Form("Random:seed = %d", random_value % 900000001));
   // print debug
   // gen->PrintDebug();
 

MC/config/PWGEM/external/generator/GeneratorCharmToEle_EvtGen.C

@@ -31,13 +31,6 @@ GeneratorCharmToEle_EvtGen(double rapidityMin = -2., double rapidityMax = 2., bo
    printf("PDG %d \n",std::stoi(spdg));
   }
   gen->SetForceDecay(kEvtSemiElectronic);
-  // set random seed
-  gen->readString("Random:setSeed on");
-  uint random_seed;
-  unsigned long long int random_value = 0; 
-  ifstream urandom("/dev/urandom", ios::in|ios::binary);
-  urandom.read(reinterpret_cast<char*>(&random_value), sizeof(random_seed));
-  gen->readString(Form("Random:seed = %d", random_value % 900000001));
   // print debug
   // gen->PrintDebug();
 

MC/config/PWGEM/external/generator/GeneratorHFToEleFull_EvtGen.C

@@ -33,13 +33,6 @@ GeneratorHFToEleFull_EvtGen(bool forcedecay = true, bool allHF = true)
   }
   if(forcedecay) gen->SetForceDecay(kEvtSemiElectronic);
   else gen->SetForceDecay(kEvtAll);
-  // set random seed
-  gen->readString("Random:setSeed on");
-  uint random_seed;
-  unsigned long long int random_value = 0; 
-  ifstream urandom("/dev/urandom", ios::in|ios::binary);
-  urandom.read(reinterpret_cast<char*>(&random_value), sizeof(random_seed));
-  gen->readString(Form("Random:seed = %d", random_value % 900000001));
   // print debug
   // gen->PrintDebug();
 

MC/config/PWGEM/external/generator/Generator_pythia8_GapTriggered_LFee.C

@@ -449,8 +449,5 @@ class GeneratorPythia8GapTriggeredLFee : public GeneratorPythia8 {
 // Predefined generators: // this function should be called in ini file.
 FairGenerator *GeneratorPythia8GapTriggeredLFee_ForEM(int inputTriggerRatio = 5, float yMin=-1.2, float yMax=1.2, int nPart = 1, int mode = -1) {
   auto myGen = new GeneratorPythia8GapTriggeredLFee(inputTriggerRatio, yMin, yMax, nPart, mode);
-  auto seed = (gRandom->TRandom::GetSeed() % 900000000);
-  myGen->readString("Random:setSeed on");
-  myGen->readString("Random:seed " + std::to_string(seed));
   return myGen;
 }

MC/config/PWGEM/external/generator/Generator_pythia8_GapTriggered_LFgamma.C

@@ -162,8 +162,5 @@ class GeneratorPythia8GapTriggeredLFgamma : public GeneratorPythia8 {
 // Predefined generators: // this function should be called in ini file.
 FairGenerator *GeneratorPythia8GapTriggeredLFgamma_ForEM(int inputTriggerRatio = 5, float yMin=-1.2, float yMax=1.2, int nPart = 1) {
   auto myGen = new GeneratorPythia8GapTriggeredLFgamma(inputTriggerRatio, yMin, yMax, nPart);
-  auto seed = (gRandom->TRandom::GetSeed() % 900000000);
-  myGen->readString("Random:setSeed on");
-  myGen->readString("Random:seed " + std::to_string(seed));
   return myGen;
 }

MC/config/PWGEM/external/generator/Generator_pythia8_forcedDecays.C

@@ -10,9 +10,8 @@ namespace eventgen {
 class DecayerPythia8ForceDecays : public DecayerPythia8 {
 public:
   DecayerPythia8ForceDecays(){
-    mPythia.readString("Random:setSeed = on");
     char* alien_proc_id = getenv("ALIEN_PROC_ID");
-    int seed;
+    long seed;
     if (alien_proc_id != NULL) {
       seed = atoi(alien_proc_id);
       LOG(info) << "Seed for DecayerPythia8 set to ALIEN_PROC_ID: " << seed;
@@ -21,7 +20,7 @@ public:
       LOG(info) << "Setting seed for DecayerPyhtia8 to 0 (random)";
       seed = 0;
     }
-    mPythia.readString("Random:seed = "+std::to_string(seed));
+    setInitialSeed(seed);
   }
   ~DecayerPythia8ForceDecays() = default;
 
@@ -109,18 +108,17 @@ class GeneratorPythia8ForcedDecays : public GeneratorPythia8 {
 
 public:
   GeneratorPythia8ForcedDecays(){
-    mPythia.readString("Random:setSeed = on");
     char* alien_proc_id = getenv("ALIEN_PROC_ID");
-    int seed;
+    long seed;
     if (alien_proc_id != NULL) {
       seed = atoi(alien_proc_id);
-      LOG(info) << "Seed for GeneratorPythia8 set to ALIEN_PROC_ID: " << seed;
+      LOG(info) << "Seed for DecayerPythia8 set to ALIEN_PROC_ID: " << seed;
     } else {
       LOG(info) << "Unable to retrieve ALIEN_PROC_ID";
-      LOG(info) << "Setting seed for GeneratorPyhtia8 to 0 (random)";
+      LOG(info) << "Setting seed for DecayerPyhtia8 to 0 (random)";
       seed = 0;
     }
-    mPythia.readString("Random:seed = "+std::to_string(seed));
+    setInitialSeed(seed);
   }
   ~GeneratorPythia8ForcedDecays() = default;
 

MC/config/PWGHF/external/generator/generator_pythia8_gaptriggered_hf.C

@@ -228,8 +228,7 @@ FairGenerator *GeneratorPythia8GapTriggeredCharm(int inputTriggerRatio, float yQ
   auto myGen = new GeneratorPythia8GapTriggeredHF(inputTriggerRatio, std::vector<int>{4}, hadronPdgList);
   auto seed = (gRandom->TRandom::GetSeed() % 900000000);
   myGen->setUsedSeed(seed);
-  myGen->readString("Random:setSeed on");
-  myGen->readString("Random:seed " + std::to_string(seed));
+  myGen->setInitialSeed(seed);
   myGen->setQuarkRapidity(yQuarkMin, yQuarkMax);
   if (hadronPdgList.size() != 0)
   {
@@ -244,8 +243,7 @@ FairGenerator *GeneratorPythia8GapTriggeredBeauty(int inputTriggerRatio, float y
   auto myGen = new GeneratorPythia8GapTriggeredHF(inputTriggerRatio, std::vector<int>{5}, hadronPdgList);
   auto seed = (gRandom->TRandom::GetSeed() % 900000000);
   myGen->setUsedSeed(seed);
-  myGen->readString("Random:setSeed on");
-  myGen->readString("Random:seed " + std::to_string(seed));
+  myGen->setInitialSeed(seed);
   myGen->setQuarkRapidity(yQuarkMin, yQuarkMax);
   if (hadronPdgList.size() != 0)
   {
@@ -260,8 +258,7 @@ FairGenerator *GeneratorPythia8GapTriggeredCharmAndBeauty(int inputTriggerRatio,
   auto myGen = new GeneratorPythia8GapTriggeredHF(inputTriggerRatio, std::vector<int>{4, 5}, hadronPdgList);
   auto seed = (gRandom->TRandom::GetSeed() % 900000000);
   myGen->setUsedSeed(seed);
-  myGen->readString("Random:setSeed on");
-  myGen->readString("Random:seed " + std::to_string(seed));
+  myGen->setInitialSeed(seed);
   myGen->setQuarkRapidity(yQuarkMin, yQuarkMax);
   if (hadronPdgList.size() != 0)
   {
@@ -279,10 +276,9 @@ FairGenerator *GeneratorPythia8GapHF(int inputTriggerRatio, float yQuarkMin = -1
   auto myGen = new GeneratorPythia8GapTriggeredHF(inputTriggerRatio, quarkPdgList, hadronPdgList);
   auto seed = (gRandom->TRandom::GetSeed() % 900000000);
   myGen->setUsedSeed(seed);
-  myGen->readString("Random:setSeed on");
-  myGen->readString("Random:seed " + std::to_string(seed));
+  myGen->setInitialSeed(seed);
   myGen->setQuarkRapidity(yQuarkMin, yQuarkMax);
   myGen->setHadronRapidity(yHadronMin, yHadronMax);
 
   return myGen;
-}
+}

MC/config/PWGLF/pythia8/generator/pythia8_inel_136tev.cfg

@@ -13,6 +13,3 @@ ParticleDecays:tau0Max = 10.
 ### phase space cuts 
 PhaseSpace:pTHatMin = 0.000000
 PhaseSpace:pTHatMax = -1.000000
-
-Random:setSeed = on
-Random:seed = 0