Use new methods to seed Pythia8

Author: sawenzel

MC/config/ALICE3/pythia8/generator_pythia8_ALICE3.C

@@ -9,7 +9,6 @@ using namespace Pythia8;
 #endif
 
 // Default pythia8 minimum bias generator
-
 class GeneratorPythia8ALICE3 : public o2::eventgen::GeneratorPythia8
 {
 public:
@@ -18,20 +17,16 @@ public:
   GeneratorPythia8ALICE3() {
 
     char* alien_proc_id = getenv("ALIEN_PROC_ID");
-    uint64_t seedFull;
-    uint64_t seed = 0;
+    int64_t seed = 0;
 
     if (alien_proc_id != NULL) {
-      seedFull = static_cast<uint64_t>(atol(alien_proc_id));
-      for(int ii=0; ii<29; ii++) // there might be a cleaner way but this will work
-        seed |= ((seedFull) & (static_cast<uint64_t>(1) << static_cast<uint64_t>(ii)));
-      LOG(info) << "Value of ALIEN_PROC_ID: " << seedFull <<" truncated to 0-28 bits: "<<seed<<endl;
+      seed = static_cast<int64_t>(atol(alien_proc_id));
     } else {
       LOG(info) << "Unable to retrieve ALIEN_PROC_ID";
       LOG(info) << "Setting seed to 0 (random)";
       seed = 0;
     }
-    mPythia.readString("Random:seed = "+std::to_string(static_cast<int>(seed)));
+    setInitialSeed(seed);
   }
 
   ///  Destructor