Using vertex from underlying event in AliSimulation (T.Kuhr)

[u/mrichter/AliRoot.git] / STEER / AliSimulation.cxx

diff --git a/STEER/AliSimulation.cxx b/STEER/AliSimulation.cxx
index 853df4ef9b4ad3d091d745bc7bf2cd89acf5714b..da034993db79deb185e2212693065a3cad3aa1a0 100644 (file)
--- a/STEER/AliSimulation.cxx
+++ b/STEER/AliSimulation.cxx
@@ -83,6 +83,7 @@
 #include "AliRun.h"
 #include "AliModule.h"
 #include "AliGenerator.h"
+#include "AliVertexGenFile.h"
 #include "AliRunDigitizer.h"
 #include "AliDigitizer.h"
 #include <TObjString.h>
@@ -107,6 +108,7 @@ AliSimulation::AliSimulation(const char* configFileName,
   fConfigFileName(configFileName),
   fGAliceFileName("galice.root"),
   fBkgrdFileNames(NULL),
+  fUseBkgrdVertex(kTRUE),
   fRegionOfInterest(kTRUE)
 {
 // create simulation object with default parameters
@@ -128,6 +130,7 @@ AliSimulation::AliSimulation(const AliSimulation& sim) :
   fConfigFileName(sim.fConfigFileName),
   fGAliceFileName(sim.fGAliceFileName),
   fBkgrdFileNames(NULL),
+  fUseBkgrdVertex(sim.fUseBkgrdVertex),
   fRegionOfInterest(sim.fRegionOfInterest)
 {
 // copy constructor
@@ -258,12 +261,26 @@ Bool_t AliSimulation::RunSimulation(Int_t nEvents)
   }
   fGAliceFileName = runLoader->GetFileName();
 
+  if (!gAlice->Generator()) {
+    Error("RunSimulation", "gAlice has no generator object. "
+         "Check your config file: %s", fConfigFileName.Data());
+    return kFALSE;
+  }
+
+  // get vertex from background file in case of merging
+  if (fUseBkgrdVertex &&
+      fBkgrdFileNames && (fBkgrdFileNames->GetEntriesFast() > 0)) {
+    Int_t signalPerBkgrd = fBkgrdFileNames->At(0)->GetUniqueID();
+    const char* fileName = ((TObjString*)
+                           (fBkgrdFileNames->At(0)))->GetName();
+    Info("RunSimulation", "The vertex will be taken from the background "
+        "file %s with nSignalPerBackground = %d", 
+        fileName, signalPerBkgrd);
+    AliVertexGenFile* vtxGen = new AliVertexGenFile(fileName, signalPerBkgrd);
+    gAlice->Generator()->SetVertexGenerator(vtxGen);
+  }
+
   if (!fRunSimulation) {
-    if (!gAlice->Generator()) {
-      Error("RunSimulation", "gAlice has no generator object. "
-           "Check your config file: %s", fConfigFileName.Data());
-      return kFALSE;
-    }
     gAlice->Generator()->SetTrackingFlag(0);
   }