MadGraph5_aMC@NLO

missing Merging options in run_card.dat

Asked by Andre Sznajder

Hi,
I have generated a VBF Z+2J process p p > Z j j , Z > l+ l- with mg5_aMC using a docker container and the run_card.dat that was created for this process is missing the options for MLM and CKKW merging.
All I could find in the run_card.dat about it is the following comment:
# To see MLM/CKKW merging options: type "update MLM" or "update CKKW"
Is there a way to create the process with a run_card.dat already containing the options for merging ?
When I try to run "update MLM" within my container I get an isntalletion error ...
Cheers,
Andre

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Olivier Mattelaer
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Best Olivier Mattelaer (olivier-mattelaer) said : 		#1

The line "update MLM" should be typed when the code is asking you to edit the cards:

Do you want to edit a card (press enter to bypass editing)?
/------------------------------------------------------------\
| 1. param : param_card.dat |
| 2. run : run_card.dat |
| 3. madanalysis5_parton : madanalysis5_parton_card.dat |
 \------------------------------------------------------------/
 you can also
   - enter the path to a valid card or banner.
   - use the 'set' command to modify a parameter directly.
     The set option works only for param_card and run_card.
     Type 'help set' for more information on this command.
   - call an external program (ASperGE/MadWidth/...).
     Type 'help' for the list of available command
 [0, done, 1, param, 2, run, 3, madanalysis5_parton, enter path][90s to answer]

Now you do not need such command per say,
you can just add the block by hand (if you know it):

 #*********************************************************************
 # Matching parameter (MLM only)
 #*********************************************************************
  0 = ickkw ! 0 no matching, 1 MLM
  1.0 = alpsfact ! scale factor for QCD emission vx
  False = chcluster ! cluster only according to channel diag
  5 = asrwgtflavor ! highest quark flavor for a_s reweight
  True = auto_ptj_mjj ! Automatic setting of ptj and mjj if xqcut >0
                                    ! (turn off for VBF and single top processes)
  0.0 = xqcut ! minimum kt jet measure between partons

Cheers,

Olivier

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Andre Sznajder (andre-sznajder) said : 		#2

Thanks Olivier Mattelaer, that solved my question.

Revision history for this message
ali (zapy76) said : 		#3

Hi Andre,

It looks like the default run_card.dat generated in your setup doesn’t include the MLM or CKKW merging options explicitly. The comment in the file suggests using "update MLM" or "update CKKW" when prompted to edit the cards, but since you're facing an installation error in your container, you can manually add the necessary settings.

You can modify run_card.dat by adding the following block under the Matching parameter (MLM only) section:

plaintext
Copy code
#*********************************************************************
# Matching parameter (MLM only)
#*********************************************************************
  0 = ickkw ! 0 no matching, 1 MLM
  1.0 = alpsfact ! scale factor for QCD emission vx
  False = chcluster ! cluster only according to channel diag
  5 = asrwgtflavor ! highest quark flavor for a_s reweight
  True = auto_ptj_mjj ! Automatic setting of ptj and mjj if xqcut > 0
                        ! (turn off for VBF and single top processes)
  0.0 = xqcut ! minimum kt jet measure between partons
If you need CKKW merging instead, similar parameters would apply, but ickkw should be set to 2 instead of 0 or 1.

Alternatively, you might want to check your Docker container's installation of MadGraph. If "update MLM" throws an installation error, it could be due to missing dependencies or an incomplete installation. Running the command outside the container or ensuring you have the latest version of MG5_aMC might resolve this issue.

Hope this helps! Let me know if you run into any other problems.
if you need further help then visit: https://essutumishi-tz.co/