.hepmc file does not contain a number of events written in index

Asked by Maksym Ovchynnikov on 2019-05-05

I ran the process p p > h, p p > h j with MG5+pythia. In the index file there is an information that after merging the number of events with the Higgs bosons is ~ 238000. However, the .hepmc file contains only ~136000 events. I have two questions about this:

1) What can be a possible reason for this? I can only guess that the reason is that at some moment of running pythia my free disk space has ended, so at the stage of joining the splits I have lost the events which oversized the disk space. What are another reasons?

2) In order to reobtain the .hepmc file, should I simply run run_shower.sh file located in the Events/run_0i directory? Will the file obtained after running this script contain correct events (i.e. only the ones which pass matching/merging)?

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Last query:
2019-05-05
Last reply:
2019-05-05

Hi,

I do not know which index you are refering to.
But in matching/merging (of MLM and CKKW-L type) you expect that ~ 50% of the events are discarded.
So this sounds quite reasonable here.

If you were using use_syst=T, then you would have kept most of those events (this is typically 5% of the events that are discarded) but then 50% of the events have a weight of 0 in the sample.

Cheers,

Olivier

> On 5 May 2019, at 13:27, Maksym Ovchynnikov <email address hidden> wrote:
>
> New question #680640 on MadGraph5_aMC@NLO:
> https://answers.launchpad.net/mg5amcnlo/+question/680640
>
> I ran the process p p > h, p p > h j with MG5+pythia. In the index file there is an information that after merging the number of events with the Higgs bosons is ~ 238000. However, the .hepmc file contains only ~136000 events. I have two questions about this:
>
>
> 1) What can be a possible reason for this? I can only guess that the reason is that at some moment of running pythia my free disk space has ended, so at the stage of joining the splits I have lost the events which oversized the disk space. What are another reasons?
>
> 2) In order to reobtain the .hepmc file, should I simply run run_shower.sh file located in the Events/run_0i directory? Will the file obtained after running this script contain correct events (i.e. only the ones which pass matching/merging)?
>
> --
> You received this question notification because you are an answer
> contact for MadGraph5_aMC@NLO.

Maksym Ovchynnikov (name-xxx) said : #2

Dear Olivier,

Sorry for unclear explanation. In run_card.dat I set the number of events to 400000. In index.html page there is written that after merging only 238000 events remained. However, this does not match the number of events in .hepmc file.

Then you should read the pythia8 log to understand what's going on.
If this is a disk space it should be written

I do not see any "run_shower.sh" script within our release. So I can not comment on such script.
The official method to re-run such part is to do
./bin/madevent
then type
pythia8 RUN_NAME_TO_SHOWER

where you need to replace RUN_NAME_TO_SHOWER by the appropriate directory name in
Events.

Cheers,

Olivier

> On 5 May 2019, at 13:52, Maksym Ovchynnikov <email address hidden> wrote:
>
> Question #680640 on MadGraph5_aMC@NLO changed:
> https://answers.launchpad.net/mg5amcnlo/+question/680640
>
> Status: Answered => Open
>
> Maksym Ovchynnikov is still having a problem:
> Dear Olivier,
>
> Sorry for unclear explanation. In run_card.dat I set the number of
> events to 400000. In index.html page there is written that after merging
> only 238000 events remained. However, this does not match the number of
> events in .hepmc file.
>
> --
> You received this question notification because you are an answer
> contact for MadGraph5_aMC@NLO.

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