MadGraph5_aMC@NLO

MadSpin getting stuck mid-event generation

Asked by Richard Ruiz on 2018-07-09

Hi Folks,

Not sure if this is a MadSpin bug or more realizing a pathological scenario. I am studying the process
generate p p > t t~ ell vv / h QCD=2 QED=2 [QCD]

and successfully generated 5M events at NLO. Events are then passed to MadSpin with the following syntax:
define tt = t t~
define bb = b b~
define ww = w+ w-
decay tt > ww bb, ww > ell vv

At around the 2h 20m mark, things looked great:
INFO: Event nb 1000000 1h 11m
INFO: Event nb 2000000 2h 23m

However, ~1200 minutes later, the command "./check" was still running but nothing to show for it. I ended up killing the process, playing with MadSpin settings like Nevents_for_max_weigth, etc., but no luck yet.

I am running 2.6.2 bzr, but not sure where and how to start debugging. I can reproduce this feature for other processes, but they all involve large event samples, so reproducing things might not be so easy. Any suggestions are more than welcome.

best,
richard