Index: trunk/MagicSoft/Mars/manalysis/MCerPhotCalc.cc
===================================================================
--- trunk/MagicSoft/Mars/manalysis/MCerPhotCalc.cc	(revision 2318)
+++ trunk/MagicSoft/Mars/manalysis/MCerPhotCalc.cc	(revision 2324)
@@ -117,15 +117,9 @@
 
     // Calculate quadratic sum of weights:
-    Double_t sum = 0;
-
     fSumQuadWeights = 0;
     for (Int_t i=0; i<fWeight.GetSize(); i++)
-        sum += fWeight[i];
-
-    for (Int_t i=0; i<fWeight.GetSize(); i++)
-    {
-        fWeight[i] /= sum;
-        fSumQuadWeights += fWeight[i]*fWeight[i];
-    }
+      fSumQuadWeights += fWeight[i]*fWeight[i];
+
+    fSumQuadWeights = sqrt(fSumQuadWeights);
 
     return kTRUE;