Merge pull request #7348 from bendavid/hepmcweightfix

Fix handling of weights in generator interfaces
cms-sw · Jan 25, 2015 · 2f457f0 · 2f457f0
1 parent 202e45c
commit 2f457f0
Show file tree

Hide file tree

Showing 4 changed files with 15 additions and 9 deletions.
diff --git a/GeneratorInterface/Core/interface/HadronizerFilter.h b/GeneratorInterface/Core/interface/HadronizerFilter.h
@@ -224,12 +224,10 @@ namespace edm
       double multihadweight = double(naccept)/double(nAttempts_);
 
       //adjust weight for GenEventInfoProduct
-      std::vector<double> genEventInfoWeights = finalGenEventInfo->weights();
-      genEventInfoWeights.push_back(multihadweight);
-      finalGenEventInfo->setWeights(genEventInfoWeights);
+      finalGenEventInfo->weights()[0] *= multihadweight;
 
       //adjust weight for HepMC GenEvent (used e.g for RIVET)
-      finalEvent->weights().push_back(multihadweight);
+      finalEvent->weights()[0] *= multihadweight;
     }
 
 

diff --git a/GeneratorInterface/Pythia8Interface/plugins/Pythia8Hadronizer.cc b/GeneratorInterface/Pythia8Interface/plugins/Pythia8Hadronizer.cc
@@ -484,7 +484,11 @@ bool Pythia8Hadronizer::hadronize()
 
   bool py8next = fMasterGen->next();
 
-  double mergeweight = fMasterGen.get()->info.mergingWeight();
+  double mergeweight = fMasterGen.get()->info.mergingWeightNLO();
+  if (fMergingHook) {
+    mergeweight *= fMergingHook->getNormFactor();
+  }
+
 
   //protect against 0-weight from ckkw or similar
   if (!py8next || std::abs(mergeweight)==0.)
@@ -516,9 +520,9 @@ bool Pythia8Hadronizer::hadronize()
     return false;
   }
 
-  //add ckkw merging weight
+  //add ckkw/umeps/unlops merging weight
   if (mergeweight!=1.) {
-    event()->weights().push_back(mergeweight);
+    event()->weights()[0] *= mergeweight;
   }
 
   if (fEmissionVetoHook) {

diff --git a/SimDataFormats/GeneratorProducts/interface/GenEventInfoProduct.h b/SimDataFormats/GeneratorProducts/interface/GenEventInfoProduct.h
@@ -25,8 +25,12 @@ class GenEventInfoProduct {
 
 	// getters
 
+	std::vector<double> &weights() { return weights_; }
 	const std::vector<double> &weights() const { return weights_; }
-	double weight() const;
+
+	double weight() const { return weights_.empty() ? 1.0 : weights_[0]; }
+
+	double weightProduct() const;
 
 	unsigned int signalProcessID() const { return signalProcessID_; }
 

diff --git a/SimDataFormats/GeneratorProducts/src/GenEventInfoProduct.cc b/SimDataFormats/GeneratorProducts/src/GenEventInfoProduct.cc
@@ -74,7 +74,7 @@ GenEventInfoProduct &GenEventInfoProduct::operator = (GenEventInfoProduct const
 	return *this;
 }
 
-double GenEventInfoProduct::weight() const
+double GenEventInfoProduct::weightProduct() const
 {
 	return std::accumulate(weights_.begin(), weights_.end(),
 	                       1., std::multiplies<double>());