KeyError : 'PYTHONPATH' when generating output

[Carli Smith]

I have imported my own UFO file into MadGraph and have generated a decay process successfully with no errors. I would now like to generate events for this process. However, whenever I try to use the "output" command it starts generating the files but then stops partway and gives me this:

Command "output" interrupted with error:
KeyError : 'PYTHONPATH'
Please report this bug on https://bugs.launchpad.net/mg5amcnlo
More information is found in 'MG5_debug'.
Please attach this file to your report.

I'm not sure if this is an issue with Python 2/3 compatibility, a simple path issue, or something wrong with the UFO file itself? I'm inclined to say this is an issue separate from MadGraph because after googling this I see this KeyError coming up a lot with other programs that use Python.

If anyone has encountered this and has some input on how to fix it, that would be much appreciated!

Thanks!

[Olivier Mattelaer (olivier-mattelaer)]

Can you attach the MG5_debug file?

forcing python2 will indeed likely fix this issue doing
PYTHONPATH= ./bin/mg5_aMC
will also likely fix the issue.

But if you give me that debug file, I will be able to have an easier fix in the next version of the code.

Thanks,

Olivier

[Carli Smith (csavannah)]

Here's the file! Sorry I forgot to attach it earlier.

On Thu, Mar 4, 2021 at 10:55 PM Olivier Mattelaer <
<email address hidden>> wrote:

> Can you attach the MG5_debug file?
>
> forcing python2 will indeed likely fix this issue doing
> PYTHONPATH= ./bin/mg5_aMC
> will also likely fix the issue.
>
> But if you give me that debug file, I will be able to have an easier fix
> in the next version of the code.
>
> Thanks,
>
> Olivier
>
> --
> You received this bug notification because you are subscribed to the bug
> report.
> https://bugs.launchpad.net/bugs/1917822
>
> Title:
> KeyError : 'PYTHONPATH' when generating output
>
> Status in MadGraph5_aMC@NLO:
> New
>
> Bug description:
> I have imported my own UFO file into MadGraph and have generated a
> decay process successfully with no errors. I would now like to
> generate events for this process. However, whenever I try to use the
> "output" command it starts generating the files but then stops partway
> and gives me this:
>
> Command "output" interrupted with error:
> KeyError : 'PYTHONPATH'
> Please report this bug on https://bugs.launchpad.net/mg5amcnlo
> More information is found in 'MG5_debug'.
> Please attach this file to your report.
>
> I'm not sure if this is an issue with Python 2/3 compatibility, a
> simple path issue, or something wrong with the UFO file itself? I'm
> inclined to say this is an issue separate from MadGraph because after
> googling this I see this KeyError coming up a lot with other programs
> that use Python.
>
> If anyone has encountered this and has some input on how to fix it,
> that would be much appreciated!
>
> Thanks!
>
> To manage notifications about this bug go to:
> https://bugs.launchpad.net/mg5amcnlo/+bug/1917822/+subscriptions
>

[Olivier Mattelaer (olivier-mattelaer)]

Thanks for the file,

Looks like this is a bug that has been already solved. So you can use one of the above trick or update your version of MG5aMC to the latest and that would fix that issue.

2.8.0 is our first official release with python3 support so I strongly suggest you to update since a lot of python3 issue have been reported with that version (as one can expect obviously)

Cheers,

Olivier