MadGraph5_aMC@NLO

Failed to produce Histograms in NLO

Asked by Justin Alvarez

Good day!

I'm new at Madgraph and I've been studying this tutorial for a while

https://indico.in2p3.fr/event/10777/contributions/3151/attachments/2242/2767/tutorial-IDPASC-2015.pdf?fbclid=IwAR23zL2P24LW6Ow2qvT3eB612ee8z2e0cqxB9-HS5U8WfkD_tnQCu99vAmU

The process is p p > t t~ [QCD]. This is an NLO process
The exercise instructs me to produce histograms after generating the event sample to be showered by Pythia6Q

After making the necessary changes in the run_card and shower_card, I got this error after simulations:

mv: cannot stat 'PY_EXE_LHAPDF': No such file or directory

I'm not sure how to solve this error since I'm sure that I successfully installed lhapdf6 using the "install" command in the MG5_aMC prompt. Thank you!

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MadGraph5_aMC@NLO Edit question
Assignee:
Paolo Torrielli Edit question
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Paolo Torrielli
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Revision history for this message
Paolo Torrielli (paolotorriell) said : 		#1

Dear Justin,

the development of Pythia6 was interrupted some years ago, so I'm not sure
it is compatible with LHAPDF6 (and probably our interface to Pythia6 is
as well incompatible with LHAPDF6).

You could check this for example by installing LHAPDF5 somewhere on your
machine, specifying this location in the file input/mg5_configuration.txt that
you find in the main MG5_aMC folder, and generating/running the process
again.

Let me know,
Cheers.
Paolo

Revision history for this message
Justin Alvarez (jialvarez14) said : 		#2

Good day Paolo,

Sorry for the inconvenience, it was just a typo on my part while I'm editing the shower_card

There's no more error but I got this message:

INFO: The file /home/jialvarez/Documents/MG5/my_ttbar_nlo/Events/run_12/plot_PYTHIA6Q_1_0.top has been generated, with histograms in the TopDrawer format, obtained by showering the parton-level file /home/jialvarez/Documents/MG5/my_ttbar_nlo/Events/run_12/events.lhe.gz with PYTHIA6Q.

It said that the histograms is in the TopDrawer format... but I don't see any figure generated. While browsing the net, it turns out that I need to convert the file to other formats before I can generate histograms (via ROOT?). Please correct me if I'm wrong.

Do I need to install other packages for Madgraph to generate the histograms instantly? Thanks!

Revision history for this message
Best Paolo Torrielli (paolo-torrielli) said : 		#3

Dear Justin,

as for the plotting facilities, histograms can be easily filled
with one of the analyses in MCatNLO/PYAnalyzer.

I recommend to use the HwU package, that produces a gnuplot file,
while top-drawer is quite old and not easy to find and install
in modern setups. In order to use HwU, you just set the ANALYSE
variable in the shower_card as

ANALYSE = py6an_HwU_pp_ttx.o HwU.o

The file py6an_HwU_pp_ttx.f, as said, is in MCatNLO/PYAnalyzer,
and can be edited at will. When the run is over, you’ll find
.gnuplot, and .pdf files in the Events/run_** folder.

Cheers.
Paolo

> On 27 Jul 2019, at 14:03, Justin Alvarez <email address hidden> wrote:
>
> Question #682347 on MadGraph5_aMC@NLO changed:
> https://answers.launchpad.net/mg5amcnlo/+question/682347
>
> Justin Alvarez posted a new comment:
> Good day Paolo,
>
> Sorry for the inconvenience, it was just a typo on my part while I'm
> editing the shower_card
>
> There's no more error but I got this message:
>
> INFO: The file
> /home/jialvarez/Documents/MG5/my_ttbar_nlo/Events/run_12/plot_PYTHIA6Q_1_0.top
> has been generated, with histograms in the TopDrawer format, obtained by
> showering the parton-level file
> /home/jialvarez/Documents/MG5/my_ttbar_nlo/Events/run_12/events.lhe.gz
> with PYTHIA6Q.
>
> It said that the histograms is in the TopDrawer format... but I don't
> see any figure generated. While browsing the net, it turns out that I
> need to convert the file to other formats before I can generate
> histograms (via ROOT?). Please correct me if I'm wrong.
>
> Do I need to install other packages for Madgraph to generate the
> histograms instantly? Thanks!
>
> --
> You received this question notification because you are subscribed to
> the question.

Revision history for this message
Justin Alvarez (jialvarez14) said : 		#4

Thanks Paolo Torrielli, that solved my question.