Systematics cannot be read by MadGraph

[mmenen]

Hi all,

first of all the relevant program version I use:
Python 3.8.2
MadMiner 0.9.3
MadGraph 3.4.0
Pythia 8.306
Delphes 3.5.0

I am trying to create an analysis with some systematics using Delphes. If I just execute the part 1 and 2b from the tutorial_particle_physics example, everything works fine. However, when I simply add systematics to part 1 of the tutorial:
miner.add_systematics("norm", norm_variation=1.1)
miner.add_systematics("scale", scale="mu", scale_variations=(0.5, 1.0, 2.0))
the MadGraph Event generation doesn't work anymore.

MadMiner itself does not give me an error but when checking the run folder in mg_processes, there is only an unweighted.lhe file.
Additionally, the MadGraph debug file gives the following error:

File "{mg_directory}/madgraph/various/systematics.py", line 191, in
self.mur=[float(i) for i in mur]
ValueError: could not convert string to float: 'b'

which seems to come from the run_card written by MadMiner, which includes the following lines:

True = use_syst ! Enable systematics studies

systematics = systematics_program ! none, systematics [python], SysCalc [depreceted, C++]
['--mur=b', '0.5', '1.0', '2.0'', '', '--muf=b'0.5,1.0,2.0'', ', ', '--together=mur', 'muf', '', '--dyn=-1''] = systematics_arguments ! see: https://cp3.irmp.ucl.ac.be/projects/madgraph/wiki/Systematics#Systematicspythonmodule

So mur and muf are written to the run_card as bytes, which MadGraph apparently can't handle.

[Sinclert]

Hi @mmenen 👋🏻

First of all, thanks for reporting this problem.

Given the valuable information you provided, I detected several issues:

• Madminer version 0.9.3. Please use latest version 0.9.5, as a couple of bug were fixed since 0.9.3.
• MadGraph version 3.4.0. We have not checked MadGraph compatibility since their 2.9.Xversions (see how we are currently installing MadGraph within the online tutorial Docker image here).

To start, could you try reproducing this error with Madminer 0.9.5 and MadGraph 2.9.X?

[Sinclert]

Hey @mmenen ! Did you try the setup I described?

[mmenen]

Hi @Sinclert, sorry for the late answer.
I have updated MadMiner to version 0.9.5 but this didn't fix the issue, so I suppose it is indeed a compatibility issue with MadGraph 3.X.
Installing and running MadGraph 2.9.X has worked for me but running the event generation with MadMiner lead to a compiling issue with gfortran. I will give an update once this is resolved.