Pass fifo to Delphes

Asked by Michael Russell on 2018-01-18

Hello,

I have some LHE events from MG5 I’m passing through Pythia8/Delphes. Since I need a huge event sample, I end up with a very large intermediate HepMC file to give to Delphes and then delete. Is it possible to pipe the pythia HepMC output directly into Delphes without writing it to disk? I see it is possible to write out HepMC to a named pipe (fifo) for use with MadAnalysis. The same thing does not seem to work for Delphes, it doesn’t read from the fifo and I just end up with an empty root file. Is there a way of doing this?

Best,
Michael

Question information

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MadGraph5_aMC@NLO Edit question
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Solved by:
Michael Russell
Solved:
2018-01-18
Last query:
2018-01-18
Last reply:
2018-01-18

Hi Michael,

I do not think that Delphes is supporting fifo file as input. But please contact them to check.
In any case, we do not support the automatic linking of the fifo (like for MA5) but you can still create the fifo via our method, and then just run Delphes on that fifo and it should work (if this possible for the Delphes code obviously).

Cheers,

Olivier

> On 18 Jan 2018, at 14:17, Michael Russell <email address hidden> wrote:
>
> New question #663227 on MadGraph5_aMC@NLO:
> https://answers.launchpad.net/mg5amcnlo/+question/663227
>
> Hello,
>
> I have some LHE events from MG5 I’m passing through Pythia8/Delphes. Since I need a huge event sample, I end up with a very large intermediate HepMC file to give to Delphes and then delete. Is it possible to pipe the pythia HepMC output directly into Delphes without writing it to disk? I see it is possible to write out HepMC to a named pipe (fifo) for use with MadAnalysis. The same thing does not seem to work for Delphes, it doesn’t read from the fifo and I just end up with an empty root file. Is there a way of doing this?
>
> Best,
> Michael
>
> --
> You received this question notification because you are an answer
> contact for MadGraph5_aMC@NLO.

Michael Russell (michael768) said : #2

Hi Olivier,

Thanks for the quick reply, I'll check with the Delphes people.

Michael