MadGraph5_aMC@NLO

Pythia8 not working with aMC@NLO

Asked by Aaron

Hi everyone!

I'm very new at this, and I am having issues using PYTHIA8 to shower with aMC@NLO. I installed PYTHIA8 correctly, and I linked to the directory in mcatnlo's configuration file. However, whenever I run a process I still get the following error at the very end:

INFO: Preparing MCatNLO run
INFO: Compiling MCatNLO for PYTHIA8...
^[[1;31mError detected in "launch auto "
write debug file /sfs/lustre/scratch/jmbcs/ttbb/run_01_tag_1_debug.log
If you need help with this issue please contact us on https://answers.launchpad.net/madgraph5
aMCatNLOError : Compilation failed, check /sfs/lustre/scratch/jmbcs/ttbb/mcatnlo.log for details^[[0m
In file included from Pythia82.cc:4:0:
/nv/blue/jmbcs/private/MG5_aMC_v2_3_0/Pythia8/include/Pythia8Plugins/HepMC2.h:14:32: fatal error: HepMC/IO_BaseClass.h: No such file or directory
 #include "HepMC/IO_BaseClass.h"
                                ^
compilation terminated.
make: *** [PythPythia8 compilation did not succeed, exiting

quit

Does anyone know how to fix this? Everything in Pythia seems to be working correctly, just not when aMC@NLO calls it. Also, I've looked around and I can't find this header file HepMC/IO_BaseClass.h anywhere.

Also, is there any way to shower events within aMC@NLO that have already been previously generated? That way I don't have to generate a whole new process and wait until the end to test/use PYTHIA8?

Thanks in advance, Aaron

Question information

Language:
English Edit question
Status:
Solved
For:
MadGraph5_aMC@NLO Edit question
Assignee:
Paolo Torrielli Edit question
Solved by:
Paolo Torrielli
Solved:
Last query:
Last reply:
Revision history for this message
Paolo Torrielli (paolo-torrielli) said : 		#1

Dear Aaron,

when installing Pythia8 it is necessary (for MG5_aMC purposes, at least) to specify the hepmc location
through the option --with-hepmc2=<path/to/hepmc2>. This way, the hepmc class in Pythia8 is recognised
properly. For more information you should run the ./configure --help command in Pythia8 and see the
options you have.

Showering without regenerating events is certainly possible. Every event generation in the process folder
ttbb creates a .lhe file and stores it in ttbb/Events/run_**/events.lhe.gz, with ** = some counter.
To shower that file you just type ./bin/shower run_** from ttbb.

Cheers.
Paolo

Revision history for this message
Aaron (jmbcs91) said : 		#2

Dear Paolo,

This makes so much more sense, thank you so much for your help! I don't see any executable in ./bin for madspin, is there any way to just decay events that have already been generated?

Thanks again,
Aaron

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

Hi Aaron,

in order to decay previously-generated events you go in ttbb,
type ‘./bin/aMCatNLO’, and this gets you into a python shell
with prompt ‘ttbb>’.

You can type ‘tab’ to see all options you have.

Among them there is ‘decay_events’: by typing ‘decay_events run_01’
you decay the events in run_01.

This will generate a new folder run_01_decayed_1 with the decayed
events.

Cheers.
Paolo

On 07 Sep 2015, at 16:42, Aaron <email address hidden> wrote:

> Question #271164 on MadGraph5_aMC@NLO changed:
> https://answers.launchpad.net/mg5amcnlo/+question/271164
>
> Status: Answered => Open
>
> Aaron is still having a problem:
> Dear Paolo,
>
> This makes so much more sense, thank you so much for your help! I don't
> see any executable in ./bin for madspin, is there any way to just decay
> events that have already been generated?
>
> Thanks again,
> Aaron
>
> --
> You received this question notification because you are subscribed to
> the question.

Revision history for this message
Aaron (jmbcs91) said : 		#4

Thanks Paolo Torrielli, that solved my question.