ExRoot running after reweighting, but before unweighted_events.lhe.gz is made

Hello MadTeam,

I am using the reweighting interface within MG5 (v2.7.2), but have had some issues using this with ExRoot as the analysis. I am reweighting the SM to several different values of a given parameter, so in reweight_card.dat I use a param_card.dat which has a scan set for that parameter. This somewhat works, and LHE files are produced successfully.

The problem arises with the ExRoot analysis step, which occurs after the reweighting weights are calculated. For some reason, this step is run before the LHE files are compressed to produce the unweighted_events.lhe.gz file. This leads to ExRoot throwing a file not found error and the files never being converted to ROOT files (see relevant output below). Of course, I can convert them myself with a short script/long bash command, but this defeats the point of having ExRoot as an analysis option in this case.

Is this a bug or am I handling something incorrectly here? Is there some easy fix I could make in the code myself to fix this behavior without having to wait for the next MG5 update?

Thanks,
Al Bee

`INFO: quit rwgt
decay_events -from_cards
INFO: Creating root files
Command "generate_events run_01" interrupted with error:
OSError : [Errno 2] No such file or directory: '(path)/Events/run_01/unweighted_events.lhe.gz'
Please report this bug on https://bugs.launchpad.net/mg5amcnlo
More information is found in (path)/run_tag_debug.log'.
Please attach this file to your report.
INFO: storing files of previous run
gzipping output file: unweighted_events.lhe
INFO: Done
INFO:`