Randomized generator selection added.

diff --git a/EVGEN/AliGenCocktail.cxx b/EVGEN/AliGenCocktail.cxx
index 0cd0a24f45c25312ebf6c88386e3e879656b11ff..fba33f80bd8b05581a5d746d7255a843dfd264b3 100644 (file)
--- a/EVGEN/AliGenCocktail.cxx
+++ b/EVGEN/AliGenCocktail.cxx
@@ -45,7 +45,7 @@ AliGenCocktail::AliGenCocktail()
     flnk2 = 0;
     fNGenerators=0;
     fEntries = 0;
-    
+    fRandom  = kFALSE;
 }
 
 AliGenCocktail::AliGenCocktail(const AliGenCocktail & cocktail):
@@ -114,6 +114,26 @@ AddGenerator(AliGenerator *Generator, const char* Name, Float_t RateExp)
        if (fStack)  entry->Generator()->SetStack(fStack);
        entry->Generator()->Init();
     }  
+
+    next.Reset();
+
+    if (fRandom) {
+       fProb.Set(fNGenerators);
+       next.Reset();
+       Float_t sum = 0.;
+       while((entry = (AliGenCocktailEntry*)next())) {
+           sum += entry->Rate();
+       } 
+
+       next.Reset();
+       Int_t i = 0;
+       Float_t psum = 0.;
+       while((entry = (AliGenCocktailEntry*)next())) {
+           psum +=  entry->Rate() / sum;
+           fProb[i++] = psum;
+       }
+    }
+       next.Reset();
 }
 
   void AliGenCocktail::FinishRun()
@@ -148,36 +168,56 @@ AddGenerator(AliGenerator *Generator, const char* Name, Float_t RateExp)
     eventVertex.Set(3);
     for (Int_t j=0; j < 3; j++) eventVertex[j] = fVertex[j];
 
-    
-  //
-    // Loop over generators and generate events
-    Int_t igen=0;
-    
-    while((entry = (AliGenCocktailEntry*)next())) {
-       igen++;
-       if (igen ==1) {
-           entry->SetFirst(0);
-       } else {
-           entry->SetFirst((partArray->GetEntriesFast())+1);
-       }
+    if (!fRandom) {
+       //
+       // Loop over generators and generate events
+       Int_t igen=0;
+       
+       while((entry = (AliGenCocktailEntry*)next())) {
+           igen++;
+           if (igen ==1) {
+               entry->SetFirst(0);
+           } else {
+               entry->SetFirst((partArray->GetEntriesFast())+1);
+           }
 //
 //      Handle case in which current generator needs collision geometry from previous generator
 //
-       gen = entry->Generator();
-       if (gen->NeedsCollisionGeometry())
-       {
-           if (preventry && preventry->Generator()->ProvidesCollisionGeometry())
+           gen = entry->Generator();
+           if (gen->NeedsCollisionGeometry())
            {
-               gen->SetCollisionGeometry(preventry->Generator()->CollisionGeometry());
-           } else {
-               Fatal("Generate()", "No Collision Geometry Provided");
+               if (preventry && preventry->Generator()->ProvidesCollisionGeometry())
+               {
+                   gen->SetCollisionGeometry(preventry->Generator()->CollisionGeometry());
+               } else {
+                   Fatal("Generate()", "No Collision Geometry Provided");
+               }
            }
+           entry->Generator()->SetVertex(fVertex.At(0), fVertex.At(1), fVertex.At(2));
+           entry->Generator()->Generate();
+           entry->SetLast(partArray->GetEntriesFast());
+           preventry = entry;
+       }  
+    } else {
+       //
+       // Select a generator randomly
+       //
+       Int_t i;
+       Float_t p0 =  gRandom->Rndm();
+
+       for (i = 0; i < fNGenerators; i++) {
+           if (p0 < fProb[i]) break;
        }
+
+       entry = (AliGenCocktailEntry*) fEntries->At(i);
+       entry->SetFirst(0);
+       gen = entry->Generator();
        entry->Generator()->SetVertex(fVertex.At(0), fVertex.At(1), fVertex.At(2));
        entry->Generator()->Generate();
        entry->SetLast(partArray->GetEntriesFast());
-       preventry = entry;
-    }  
+    }
+    
+    
     next.Reset();
 // Header
     AliGenEventHeader* header = new AliGenEventHeader("AliGenCocktail");

diff --git a/EVGEN/AliGenCocktail.h b/EVGEN/AliGenCocktail.h
index 8883b6a0826ff776fc3f06b0175475d903b50953..c233ebc8320220408bd17c582e83a984cb04d7d4 100644 (file)
--- a/EVGEN/AliGenCocktail.h
+++ b/EVGEN/AliGenCocktail.h
@@ -11,8 +11,10 @@
 //
 
 #include "AliGenerator.h"
+#include <TArrayF.h>
 
 class AliGenCocktailEntry;
+class TArrayF;
 
 
 class AliGenCocktail : public AliGenerator
@@ -26,6 +28,8 @@ class AliGenCocktail : public AliGenerator
     virtual void FinishRun();
     virtual void Generate();
     virtual void SetVertexSmear(VertexSmear_t smear);
+    virtual void SetRandomise(Bool_t flag) {fRandom = flag;}
+           
     //
     // Add a new generator to the list
     virtual void AddGenerator
@@ -40,9 +44,12 @@ class AliGenCocktail : public AliGenerator
 
  protected:
     Int_t fNGenerators;   // Number of generators booked
+    Bool_t fRandom;       // Flag to select random generator from list
+    TArrayF  fProb;       // Probability of an event (if fRandom == kTRUE)
     TList  *fEntries;     // List of Generators
     TObjLink *flnk1;      // ! Iterator for first generator
     TObjLink *flnk2;      // ! Iterator for second generator
+    
 //
  private:
     void Copy(TObject &arun) const;