Merge pull request #49082 from cms-ngt-hlt/hotfix/division_by_zero

[Hotfix] MET Validation: Division by zero

Author: cmsbuild

Validation/RecoMET/plugins/METTester.h

@@ -41,10 +41,10 @@ class METTester : public DQMEDAnalyzer {
   void bookHistograms(DQMStore::IBooker &, edm::Run const &, edm::EventSetup const &) override;
   static void fillDescriptions(edm::ConfigurationDescriptions &);
 
-  static const int mNMETBins = 11;
+  static constexpr int mNMETBins = 11;
   static constexpr std::array<float, mNMETBins + 1> mMETBins = {
       {0., 20., 40., 60., 80., 100., 150., 200., 300., 400., 500., 1000.}};
-  static const int mNPhiBins = 6;
+  static constexpr int mNPhiBins = 6;
   static constexpr std::array<float, mNPhiBins + 1> mPhiBins = {{-3.15, -2., -1., 0., 1., 2., 3.15}};
 
   static std::string binStr(float left, float right, bool roundInt = true);

Validation/RecoMET/plugins/METTesterPostProcessor.cc

@@ -37,6 +37,8 @@ void METTesterPostProcessor::dqmEndJob(DQMStore::IBooker &ibook_, DQMStore::IGet
   }
 }
 
+bool METTesterPostProcessor::mCheckHisto(MElem *h) { return h && h->getRootObject(); }
+
 void METTesterPostProcessor::mFillAggrHistograms(std::string metdir, DQMStore::IGetter &iget) {
   for (std::string bt : {"MET", "Phi"}) {  // loop over bin types
     for (unsigned idx = 0; idx < mNBins[bt]; ++idx) {
@@ -46,12 +48,27 @@ void METTesterPostProcessor::mFillAggrHistograms(std::string metdir, DQMStore::I
       mArrayIdx<MElem *>(mMETDiff_GenMETTrue[bt], idx) = iget.get(metdir + "/METDiff_GenMETTrue_" + bt + edges);
       mArrayIdx<MElem *>(mMETRatio_GenMETTrue[bt], idx) = iget.get(metdir + "/METRatio_GenMETTrue_" + bt + edges);
       mArrayIdx<MElem *>(mMETDeltaPhi_GenMETTrue[bt], idx) = iget.get(metdir + "/METDeltaPhi_GenMETTrue_" + bt + edges);
+
+      // check one object, if it exists, then the remaining ME's exists too
+      // for genmet none of these ME's are filled
+      if (mCheckHisto(mArrayIdx<MElem *>(mMETDiff_GenMETTrue[bt], 0))) {
+        // log histograms with zero entries
+        if (mArrayIdx<MElem *>(mMET[bt], idx)->getEntries() < mEpsilonDouble ||
+            mArrayIdx<MElem *>(mMETDiff_GenMETTrue[bt], idx)->getEntries() < mEpsilonDouble ||
+            mArrayIdx<MElem *>(mMETRatio_GenMETTrue[bt], idx)->getEntries() < mEpsilonDouble ||
+            mArrayIdx<MElem *>(mMETDeltaPhi_GenMETTrue[bt], idx)->getEntries() < mEpsilonDouble) {
+          LogDebug("METTesterPostProcessor")
+              << "At least one of the " << bt + edges << " histograms has zero entries:\n"
+              << "  MET: " << mArrayIdx<MElem *>(mMET[bt], idx)->getEntries() << "\n"
+              << "  METDiff: " << mArrayIdx<MElem *>(mMETDiff_GenMETTrue[bt], idx)->getEntries() << "\n"
+              << "  METRatio: " << mArrayIdx<MElem *>(mMETRatio_GenMETTrue[bt], idx)->getEntries() << "\n"
+              << "  METDeltaPhi: " << mArrayIdx<MElem *>(mMETDeltaPhi_GenMETTrue[bt], idx)->getEntries();
+        }
+      }
     }
 
-    // check one object, if it exists, then the remaining ME's exists too
-    // for genmet none of these ME's are filled
-    if (mArrayIdx<MElem *>(mMETDiff_GenMETTrue[bt], 0) &&
-        mArrayIdx<MElem *>(mMETDiff_GenMETTrue[bt], 0)->getRootObject()) {
+    if (mCheckHisto(mArrayIdx<MElem *>(mMETDiff_GenMETTrue[bt], 0))) {
+      // compute and store MET quantities
       for (unsigned idx = 0; idx < mNBins[bt]; ++idx) {
         mMETDiffAggr[bt]->setBinContent(idx + 1, mArrayIdx<MElem *>(mMETDiff_GenMETTrue[bt], idx)->getMean());
         mMETDiffAggr[bt]->setBinError(idx + 1, mArrayIdx<MElem *>(mMETDiff_GenMETTrue[bt], idx)->getRMS());
@@ -67,11 +84,13 @@ void METTesterPostProcessor::mFillAggrHistograms(std::string metdir, DQMStore::I
         mMETResolAggr[bt]->setBinContent(idx + 1, metRMS);
         mMETResolAggr[bt]->setBinError(idx + 1, resolError);
 
-        float significance = metMean / metRMS;
+        float significance = metRMS < mEpsilonFloat ? 0.f : metMean / metRMS;
+        float significance_error = metRMS < mEpsilonFloat || metMean < mEpsilonFloat
+                                       ? 0.f
+                                       : significance * std::sqrt((metRMS * metRMS / (metMean * metMean)) +
+                                                                  (resolError * resolError / (metRMS * metRMS)));
         mMETSignAggr[bt]->setBinContent(idx + 1, significance);
-        mMETSignAggr[bt]->setBinError(idx + 1,
-                                      significance * std::sqrt((metRMS * metRMS / (metMean * metMean)) +
-                                                               (resolError * resolError / (metRMS * metRMS))));
+        mMETSignAggr[bt]->setBinError(idx + 1, significance_error);
       }
     }
   }

Validation/RecoMET/plugins/METTesterPostProcessor.h

@@ -22,9 +22,11 @@ class METTesterPostProcessor : public DQMEDHarvester {
   void dqmEndJob(DQMStore::IBooker&, DQMStore::IGetter&) override;
   std::vector<std::string> met_dirs;
 
+  using MElem = MonitorElement;
+
   void mFillAggrHistograms(std::string, DQMStore::IGetter&);
+  bool mCheckHisto(MElem* h);
 
-  using MElem = MonitorElement;
   template <typename T>
   using ArrayVariant = std::variant<std::array<T, METTester::mNMETBins + 1>, std::array<T, METTester::mNPhiBins + 1>>;
 
@@ -59,6 +61,9 @@ class METTesterPostProcessor : public DQMEDHarvester {
   ElemMap mMETSignAggr;
 
   std::string runDir;
+
+  float mEpsilonFloat = std::numeric_limits<float>::epsilon();
+  double mEpsilonDouble = std::numeric_limits<double>::epsilon();
 };
 
 #endif