From 4359dac6f489acb50673546507d5fd35c8e0d154 Mon Sep 17 00:00:00 2001
From: maria <dalfonso@cern.ch>
Date: Sat, 20 Aug 2016 11:50:08 +0200
Subject: [PATCH] M3-HLT: added protection for potential divisions by zero

---
 .../interface/HcalDeterministicFit.h          | 19 ++++++++++++++++---
 .../HcalRecAlgos/src/HcalDeterministicFit.cc  | 19 ++++++++++++++++---
 2 files changed, 32 insertions(+), 6 deletions(-)

diff --git a/RecoLocalCalo/HcalRecAlgos/interface/HcalDeterministicFit.h b/RecoLocalCalo/HcalRecAlgos/interface/HcalDeterministicFit.h
index f6cc6afa61630..b4fcfe996f815 100644
--- a/RecoLocalCalo/HcalRecAlgos/interface/HcalDeterministicFit.h
+++ b/RecoLocalCalo/HcalRecAlgos/interface/HcalDeterministicFit.h
@@ -120,9 +120,21 @@ void HcalDeterministicFit::apply(const CaloSamples & cs, const std::vector<int>
   float n5=0;
   getLandauFrac(-tsShift5+tsWidth,-tsShift5+tsWidth*2,n5);
 
-  float ch3=corrCharge[3]/i3;
-  float ch4=(i3*corrCharge[4]-n3*corrCharge[3])/(i3*i4);
-  float ch5=(n3*n4*corrCharge[3]-i4*nn3*corrCharge[3]-i3*n4*corrCharge[4]+i3*i4*corrCharge[5])/(i3*i4*i5);
+  float ch3=0;
+  float ch4=0;
+  float ch5=0;
+
+  if(i3==0 || i4==0 || i5==0) {
+
+    ch3=0;
+    ch4=0;
+    ch5=0;
+
+  } else {
+
+    ch3=corrCharge[3]/i3;
+    ch4=(i3*corrCharge[4]-n3*corrCharge[3])/(i3*i4);
+    ch5=(n3*n4*corrCharge[3]-i4*nn3*corrCharge[3]-i3*n4*corrCharge[4]+i3*i4*corrCharge[5])/(i3*i4*i5);
 
     if (ch3<negThresh[0]) {
       ch3=negThresh[0];
@@ -140,6 +152,7 @@ void HcalDeterministicFit::apply(const CaloSamples & cs, const std::vector<int>
         tsShift4=invG;
       }
     }
+  }
 
   if (ch3<1) {
     ch3=0;
diff --git a/RecoLocalCalo/HcalRecAlgos/src/HcalDeterministicFit.cc b/RecoLocalCalo/HcalRecAlgos/src/HcalDeterministicFit.cc
index 6b0ad64a5a12f..d0bbff97341c7 100644
--- a/RecoLocalCalo/HcalRecAlgos/src/HcalDeterministicFit.cc
+++ b/RecoLocalCalo/HcalRecAlgos/src/HcalDeterministicFit.cc
@@ -110,9 +110,21 @@ void HcalDeterministicFit::phase1Apply(const HBHEChannelInfo& channelData,
   float n5=0;
   getLandauFrac(-tsShift5+tsWidth,-tsShift5+tsWidth*2,n5);
 
-  float ch3=corrCharge[3]/i3;
-  float ch4=(i3*corrCharge[4]-n3*corrCharge[3])/(i3*i4);
-  float ch5=(n3*n4*corrCharge[3]-i4*nn3*corrCharge[3]-i3*n4*corrCharge[4]+i3*i4*corrCharge[5])/(i3*i4*i5);
+  float ch3=0;
+  float ch4=0;
+  float ch5=0;
+
+  if(i3==0 || i4==0 || i5==0) {
+
+    ch3=0;
+    ch4=0;
+    ch5=0;
+
+  } else {
+
+    ch3=corrCharge[3]/i3;
+    ch4=(i3*corrCharge[4]-n3*corrCharge[3])/(i3*i4);
+    ch5=(n3*n4*corrCharge[3]-i4*nn3*corrCharge[3]-i3*n4*corrCharge[4]+i3*i4*corrCharge[5])/(i3*i4*i5);
 
     if (ch3<negThresh[0]) {
       ch3=negThresh[0];
@@ -130,6 +142,7 @@ void HcalDeterministicFit::phase1Apply(const HBHEChannelInfo& channelData,
         tsShift4=invG;
       }
     }
+  }
 
   if (ch3<1) {
     ch3=0;