MadGraph5_aMC@NLO

Is the event generation from a lhe file using pythia random when used multiple times?

Asked by Olivier Dupon

Dear MadGraph experts,

I currently want to generate around 300k events from models used in MadGraph. For this I have to use a stand-alone pythia program. My current idea is to let MadGraph generate an 30k lhe file which I want to then let run through pythia 10 times parallel.
The question I have for this, however, is whether this will be random or will just generate the same 30k events 10 times since iseed is already set in run_card and the general data about the events is already given.

Kind regards
Olivier Dupon

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Olivier Mattelaer
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Best Olivier Mattelaer (olivier-mattelaer) said : 		#1

If you run like this
./bin/madevent
multi_run 10
set nevents 30k

Then you will certainly have 10 independent sample.
If you create 10 different directory and run like this
./bin/generate_events
set nevents 30k

Then your events will be correlated in all the different directories. In that case, you will need to set the seed manually to a different value in each directories to avoid correlations.

Cheers,

Olivier

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Olivier Dupon (odupon) said : 		#2

Thanks Olivier Mattelaer, that solved my question.