Run terminated at pythia8 parallelization step

[Himangshu Neog]

Hi,
I am new to MadGraph5 and I am getting the following error which seems to exist when I run more than 1000 events but not when I am running only 100 events. The terminal error is:

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=== Results Summary for run: run_01 tag: tag_1 ===

     Cross-section : 0.004327 +- 2.708e-05 pb
     Nb of events : 300

store_events
INFO: Storing parton level results
INFO: End Parton
reweight -from_cards
decay_events -from_cards
INFO: Running Pythia8 [arXiv:1410.3012]
No user-defined value for Pythia8 parameter 'JetMatching:nJetMax'. Setting it automatically to 2.
Splitting .lhe event file for PY8 parallelization...
Submitting Pythia8 jobs...
Pythia8 shower jobs: 0 Idle, 2 Running, 0 Done [0 second]
/home/supercdms/Documents/monotop/Events/run_01/PY8_parallelization/run_PY8.sh: line 2: 29370 Segmentation fault (core dumped) ./MG5aMC_PY8_interface PY8Card.dat &> PY8_log.txt
WARNING: program /home/supercdms/Documents/monotop/Events/run_01/PY8_parallelization/run_PY8.sh 1 launch ends with non zero status: 139. Stop all computation
/home/supercdms/Documents/monotop/Events/run_01/PY8_parallelization/run_PY8.sh: line 2: 29369 Terminated ./MG5aMC_PY8_interface PY8Card.dat &> PY8_log.txt
Pythia8 shower jobs: 0 Idle, 1 Running, 1 Done [19 seconds]
Pythia8 shower jobs: 0 Idle, 0 Running, 2 Done [19 seconds]
Command "generate_events run_01" interrupted with error:
Exception : program /home/supercdms/Documents/monotop/Events/run_01/PY8_parallelization/run_PY8.sh 1 launch ends with non zero status: 139. Stop all computation
Please report this bug on https://bugs.launchpad.net/mg5amcnlo
More information is found in '/home/supercdms/Documents/monotop/run_01_tag_1_debug.log'.
Please attach this file to your report.
INFO: storing files of previous run
INFO: Done

File attached.
Thanks

[Valentin Hirschi (valentin-hirschi)]

Can you confirm that the problem only happens when parallelizing Pythia8 shower?
In other terms, if you run

set nb_core 1

just before you launch the shower in the madgraph run interface, does it go through?

In any case, please share the content of the log file produced by Pythia8, i.e.

/home/supercdms/Documents/monotop/Events/run_01/PY8_parallelization/PY8_log.txt

it may well be that the error is Pythia8-specific and should therefore be addressed to Pythia8's authors.