Index: trunk/MagicSoft/Mars/macros/RanForest.C
===================================================================
--- trunk/MagicSoft/Mars/macros/RanForest.C	(revision 1870)
+++ trunk/MagicSoft/Mars/macros/RanForest.C	(revision 1871)
@@ -103,7 +103,7 @@
 
     MRanForestGrow rfgrow2;
-    rfgrow2.SetNumTrees(50);
+    rfgrow2.SetNumTrees(10);
     rfgrow2.SetNumTry(3);
-    rfgrow2.SetNdSize(1);
+    rfgrow2.SetNdSize(10);
 
     MWriteRootFile rfwrite2("RF.root");
@@ -114,4 +114,11 @@
     tlist2.AddToList(&rfwrite2);
     tlist2.AddToList(&fillh2);
+
+    // gRandom is accessed from MRanForest (-> bootstrap aggregating)
+    // and MRanTree (-> random split selection) and should be initialized
+    // here if you want to set a certain random number generator
+    if(gRandom)
+        delete gRandom;
+    gRandom = new TRandom3(0);
 
     //
Index: trunk/MagicSoft/Mars/manalysis/MRanForest.cc
===================================================================
--- trunk/MagicSoft/Mars/manalysis/MRanForest.cc	(revision 1870)
+++ trunk/MagicSoft/Mars/manalysis/MRanForest.cc	(revision 1871)
@@ -226,5 +226,9 @@
     {
         if(!gRandom)
-            gRandom=new TRandom3(0);
+        {
+            *fLog << err << dbginf << "gRandom not initialized... aborting." << endl;
+            return kFALSE;
+        }
+
         Int_t k=Int_t(fNumData*gRandom->Rndm());
 
Index: trunk/MagicSoft/Mars/manalysis/MRanTree.cc
===================================================================
--- trunk/MagicSoft/Mars/manalysis/MRanTree.cc	(revision 1870)
+++ trunk/MagicSoft/Mars/manalysis/MRanTree.cc	(revision 1871)
@@ -41,4 +41,7 @@
 #include "MDataArray.h"
 
+#include "MLog.h"
+#include "MLogManip.h"
+
 ClassImp(MRanTree);
 
@@ -178,4 +181,9 @@
 
     // random split selection, number of trials = fNumTry
+    if(!gRandom)
+    {
+        *fLog << err << dbginf << "gRandom not initialized... aborting." << endl;
+        return kFALSE;
+    }
     for(Int_t mt=0;mt<fNumTry;mt++)
     {