From f885bbe35efb99b46951060baecfb83d7a03585d Mon Sep 17 00:00:00 2001
From: Florian Uhlig <f.uhlig@gsi.de>
Date: Tue, 11 Mar 2025 13:16:07 +0100
Subject: [PATCH] Fix Geant4 configuration
With the additional parameter specialCuts the energy based Geant3 cuts are
automatically converted to the range based Geant4 cuts by VMC. Without the
parameter the default Geant4 cuts are used. The change reduced the number of
secondaries by a factor of 5 or more for a normal CbmRoot UrQMD simulation and
speed up the runtime by factors. The runtime compared to Geant3 went from being
slower by a factor of 4 to being slower by 30 %.
The change of the maximum number of steps from 1e7 to the correct number of
10000 has no effect. There are no tracks exceeding 10000 steps such that there
is no additional speedup.
---
sim/transport/steer/CbmGeant4Settings.h | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/sim/transport/steer/CbmGeant4Settings.h b/sim/transport/steer/CbmGeant4Settings.h
index 6b58e44dee..9c1082df41 100644
--- a/sim/transport/steer/CbmGeant4Settings.h
+++ b/sim/transport/steer/CbmGeant4Settings.h
@@ -1,4 +1,4 @@
-/* Copyright (C) 2020 GSI Helmholtzzentrum fuer Schwerionenforschung, Darmstadt
+/* Copyright (C) 2020-2025 GSI Helmholtzzentrum fuer Schwerionenforschung, Darmstadt
SPDX-License-Identifier: GPL-3.0-only
Authors: Florian Uhlig [committer] */
@@ -95,7 +95,7 @@ public:
Int_t GetMaximumNumberOfSteps() { return fMaxNumSteps; }
private:
- std::array<std::string, 3> fG4RunConfig {{"geomRoot", "QGSP_BERT_EMV+optical", "stepLimiter"}};
+ std::array<std::string, 3> fG4RunConfig {{"geomRoot", "QGSP_BERT_EMV+optical", "stepLimiter+specialCuts"}};
/*
See https://redmine.cbm.gsi.de/issues/2913
@@ -110,7 +110,7 @@ private:
"/process/optical/processActivation OpAbsorption true",
"/process/optical/processActivation OpBoundary true"};
- Int_t fMaxNumSteps {10000000};
+ Int_t fMaxNumSteps {10000};
Int_t fRandomSeed {0};
--
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