MadGraph5_aMC@NLO

submit pgs on multiple cores

Asked by Hiren Patel

I have an iMac with Intel i7 which is a multicore processor.
I noticed that if run madgraph/pythia/pgs using

launch -m

I notice that the parton-level simulation is done on multiple cores (good!)
but once it moves to pythia and pgs, it switches to one core.

Is there a way to run these parts of the simulation on multiple cores to speed up the computation time?
Thanks!

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Johan Alwall
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Best Johan Alwall (johan-alwall) said : 		#1

Hello Hiren,

Unfortunately, there is no way to do this automatically at present. What you would need to do is split up the unweighted_events.lhe event file from the MadEvent run into a number of smaller pieces, and then run Pythia and PGS for each piece. Note that they have to be run in separate directories, since the output/input files for Pythia and PGS have fixed file names.

Also note that a significant fraction of the effort in running Pythia and PGS are in disk i/o, so it's not clear that you would speed up the generation so much by running multiple sessions in parallel.

All the best,
Johan

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Hiren Patel (hhpatel) said : 		#2

Wow Johan,

Thanks for the quick and clear response! I guess I should buy a computer with more HD next time ;)

-Hiren Patel

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Hiren Patel (hhpatel) said : 		#3

Thanks Johan Alwall, that solved my question.