Generating 200k events using Madgraph-Pythia-Delphes interface

Hi,

The idea of the multi-run is exactly to run pythia/Delphes on each subsample but not on the merged one.

So this is expected.

Cheers,

Olivier

On Apr 24, 2014, at 7:41 PM, ushoshi maitra <email address hidden> wrote:

> New question #247589 on MadGraph5_aMC@NLO:
> https://answers.launchpad.net/mg5amcnlo/+question/247589
>
> Hi
> I'm working in MG5_aMC_2.1.0 . I need to generate more than 50k events for my background as well as signal. I'm generating the events at the parton level and then I'm showering it with pythia followed by the delphes detector simulation in madgraph. However when I'm using the ./bin/madevent/multi_run command for this chain somehow delphes is not running.
> Also the final merged run has only the parton level LHE and root files. I'm little bit confused at this stage. Do I have to run delphes and pythia separately for this combined set of events. Even when I'm selecting Pythia as well as Delphes switch it is showing:
> INFO: Running Pythia
> INFO: Creating Pythia LHE File
> Running hep2lhe
> pythia_events.lhe file generated, with simple jet clustering
> Warning! Never use this file for detector studies!
> INFO: Warning! Never use this pythia lhe file for detector studies!
> INFO: Creating Pythia LHE Root File
> ** Calculating number of events to process. Please wait...
> ** Input file contains 0 events
> ** Exiting...
> INFO: Creating Plots for Pythia level
> INFO: Plots for pythia level generated, see /home/ushoshi/Applications/Mad5/MG5_aMC_v2_0_2/PROC_sm_0/HTML/run_01_1/plots_pythia_tag_1.html
> INFO: End Plots for pythia level
> INFO: finish
> INFO: No pgs_card detected, so not run pgs
> INFO: prepare delphes run
> INFO: No delphes_card detected, so not run Delphes
>
> Am I doing something wrong or delphes and pythia is not supported for madgraph multi_run option. Is there any option so that I can generate 100k events at the Delphes level after pythia shower in madgraph. I'm using the default pythia and delphes version. Looking forward for your help.
>
> Thanks in advance.
>
>
> Ushoshi
>
>
> --
> You received this question notification because you are an answer
> contact for MadGraph5_aMC@NLO.

Thanks a lot for your quick answer. I just want to know if I want to run Delphes/Pythia on the merged file do I have to run it separately in madevent. Also can you please tell me why we can not generate more than 50k events?

Thanks again!

Ushoshi

Hi,

Actually since the begin of the week, you should be able to generate more than 50k.
They are actually two problem with large file.

1) In madevent, we need to ensure that the order in the events are random, this cpu-time of this operation raise as N^2 (N is the number of events generated).
So generating 2 sample of N/2 sample is at a point faster than 1 sample of N events (for N large obviously).

2) The stdhep format was limited to 4 Go (due to some index in 32Go). Therefore pythia was not able to handle correctly huge number of events.
Pavel just define at the begin of the week a new STDHEP format making the index in 64 bit. The support of this new format is currently limited.
But this should fix the problem of the limitation of the number of events.

Cheers,

Olivier

On Apr 25, 2014, at 8:41 AM, ushoshi maitra <email address hidden> wrote:

> Question #247589 on MadGraph5_aMC@NLO changed:
> https://answers.launchpad.net/mg5amcnlo/+question/247589
>
> Status: Answered => Open
>
> ushoshi maitra is still having a problem:
> Thanks a lot for your quick answer. I just want to know if I want to run
> Delphes/Pythia on the merged file do I have to run it separately in
> madevent. Also can you please tell me why we can not generate more than
> 50k events?
>
> Thanks again!
>
>
> Ushoshi
>
> --
> You received this question notification because you are an answer
> contact for MadGraph5_aMC@NLO.

Dear Olivier,
                      I have a question in this issue.
>Actually since the begin of the week, you should be able to generate more than 50k.

Is it possible to generate more than 50k merged events in a single run?

Regards,
Goutam

Yes.

Olivier