Okay, I added the code to common_run_interface.py, but there was no change to the output, that is there were no diagnostic out lines. While I saved the python file I did nothing else. Do I need to recompile it or something like that? When I run with just one core (set nb_core 1) I get the same error: INFO: Create matching plots for Pythia8 *Command "shower pythia8 sm_ee_bbbbvv_QCD_0_hhvv_1TeV_50k_pyde -f" interrupted with error:* *IndexError : list index out of range* I should mention that I have used the parallel pythia8 for other processes and everything has worked fine. I've attached the log from the last run, in case it is useful. However, it seems that my changing the python code did not affect anything. Thanks for the help, On Mon, Jul 24, 2017 at 2:59 PM, Valentin Hirschi <