From 135b60d8b521f00585e2d766c83aaabaad164af3 Mon Sep 17 00:00:00 2001
From: Simone Pagan Griso <simone.pagan.griso@cern.ch>
Date: Mon, 10 Aug 2020 11:56:56 -0700
Subject: [PATCH] add additional early protection against failure to balance
energy
---
Generators/Pythia8_i/src/UserHooks/DecayToSUEP.cxx | 13 ++++++++++---
Generators/Pythia8_i/src/UserHooks/suep_shower.cxx | 7 +++++++
2 files changed, 17 insertions(+), 3 deletions(-)
diff --git a/Generators/Pythia8_i/src/UserHooks/DecayToSUEP.cxx b/Generators/Pythia8_i/src/UserHooks/DecayToSUEP.cxx
index d52df4bba1d..9f526e847d4 100644
--- a/Generators/Pythia8_i/src/UserHooks/DecayToSUEP.cxx
+++ b/Generators/Pythia8_i/src/UserHooks/DecayToSUEP.cxx
@@ -133,15 +133,22 @@ namespace Pythia8{
try {
nShowerAttempts++;
suep_shower4momenta=suep_shower.generate_shower();
- nShowerAttempts = -1; //exit condition
+ if( suep_shower4momenta.size()<3){
+ //Failed to balance energy or less than 3 particles in the shower
+ //Try again until nShowerAttempts >= 3
+ } else {
+ //All ok!
+ nShowerAttempts = -1; //exit condition
+ }
} catch (std::exception &e) {
//Failed to generate the shower!
- //Can happen in some rare circumstances, try again
+ //Can happen in some rare circumstances,
+ //Try again until nShowerAttempts >= 3
}
} while ((nShowerAttempts > 0) && (nShowerAttempts < 3));
if (nShowerAttempts >= 3) {
//Something is seriously wrong then, print warning and skip to next event
- std::cout << "[SUEP] ERROR: Something went terribly wrong in generating the shower. Skipping the event." << std::endl;
+ std::cout << "[SUEP] WARNING: Something went wrong in generating the shower. Skipping the event." << std::endl;
return true; //veto the event!
}
diff --git a/Generators/Pythia8_i/src/UserHooks/suep_shower.cxx b/Generators/Pythia8_i/src/UserHooks/suep_shower.cxx
index 08c9ea67ad5..f6404d3d71b 100644
--- a/Generators/Pythia8_i/src/UserHooks/suep_shower.cxx
+++ b/Generators/Pythia8_i/src/UserHooks/suep_shower.cxx
@@ -146,6 +146,13 @@ vector< Vec4 > Suep_shower::generate_shower(){
event[n][i] += correction;
}
}
+
+ //Shield against an exception in the calculation of "p_scale" further down. If it fails, abort the event.
+ if(Suep_shower::reballance_func(2.0,event)<0.0){
+ // failed to balance energy.
+ event.clear();
+ return event;
+ }
// finally, ballance the total energy, without destroying momentum conservation
tolerance tol = 0.00001;
--
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