Instructions for MC contacts

Hi! I have been an MC contact for EGM POG since 2021. If you recently started as a MC contact for EGM, you will find very useful tools and links in this webpage.

ℹ️ This webpage is useful for CMS members only.

Getting started

Registering as an MC contact

  1. First, register as a "user" on the MccM website by visiting this link.
  2. After registering, send an email to PdmV at cmstalk+pnr@dovecotmta.cern.ch requesting an increase in your role from "user" to "generator contact" on the development version of the MccM website (mcm-dev).
  3. Once your role is updated, you will gain access to the website. You will then receive a questionnaire that you need to fill out before starting as an official MC contact.
  • For details on placing requests, MC tools, naming conventions, and other aspects of MC production, visit the MC production GitBook.
  • Start with this introduction page.
  • When filling out the questionnaire, refer to the MC contact section.
  • An MC contact is required to attend the MC coordination meeting on Wednesday at 15:00 (CERN time). Links to past meetings and other useful information can be found in the TWiki, or in the Indico link.
  • This GitLab issues page is used to handle requests raised by MC contacts.

Work description

An MC contact in CMS serves as the main liaison for Monte Carlo production for the respective physics groups (like NPS, EGM, EXO ... etc.). The responsibilities include creating and validating MC requests, ensuring proper use of naming conventions, coordinating with PdmV and other MC contacts, attending weekly coordination meetings, reporting issues, and providing support to group members in accessing and using MC datasets effectively.

The following contains some useful information on what to do and how to proceed.

I find it convenient to search for different things using wildcards in html links. The following are a few examples.

  • Search for requests can be done by combining wildcards with the query parameters such as prepid, dataset_name etc. For example, 
    
https://cms-pdmv-prod.web.cern.ch/mcm/requests?prepid=*Run3Winter24*GS*
https://cms-pdmv-prod.web.cern.ch/mcm/requests?prepid=*Run3Winter24*GS*&dataset_name=DY*
  • Search for tickets and chains is also done in a similar way. 
    
https://cms-pdmv-prod.web.cern.ch/mcm/mccms?prepid=EGM-2024*
https://cms-pdmv-prod.web.cern.ch/mcm/chained_campaigns?prepid=chain_Run3Summer23wmLHEGS_*

Cloning an old request for a new campaign

For EGM, new MC requests often use older requests as templates, since the gridpack and underlying physics are the same. Finding the appropriate GEN-SIM request that starts with the correct gridpack allows it to be cloned for new campaigns, with an updated production chain that goes from GEN-SIM, DIGI-RAW ... all the way to NanoAOD. More on the MC production workflow can be found in this example which demonstrates how to produce NanoAOD, starting with a gridpack in lxplus.

  • Find a GEN-SIM request of the following form: POG-Campaign-*GS-xxxx. Example: EGM-RunIII2024Summer24wmLHEGS-00002
  • Click the Clone button next to it, and choose the target campaign.
  • On the next page, you can modify parameters such as dataset name, total events required, etc.
  • Next step is validation.

Validating a request

  • For local validation on the lxplus master node, go to the request and click the Get setup command button to retrieve a shell script.
  • This script sets up the working environment with the appropriate SCRAM_ARCH and CMSSW, and runs the LHE-to-GENSIM tool for a subset of events. Ensure you have enough space in your work area and that the lxplus version is compatible with the SCRAM_ARCH.
  • After producing a certain number of events (may take up to ~100 seconds per event), it will display time per event and size per event estimates.
  • If local validation is successful, you can update the time/event and size/event in the request itself.
  • Run central validation by clicking the Next step button.
  • A successful validation report will be sent via CERN email. After this, a ticket can be assigned to the request.

Creating a GitLab issue for follow-up

  • Before creating a ticket, consult with PdmV in the weekly MccM meetings.
  • First, create a GitLab issue here: GitLab MccM issues, mentioning the requests and number of tickets.
  • Ask for the appropriate production chain, which flows from GENSIM all the way to NanoAOD. Note that some non-standard requests require specific formats like EGMNano or ALCARECO. In those cases, the chain will be different and must be created for the specific purpose. This is handled by PdmV.

Creating a ticket for one or more requests

  • After confirming with PdmV, create a new ticket here: MccM tickets.
  • Attach the production chain and the request(s) to the ticket. (Typically one ticket is recommended for one request, but sometimes one ticket can be assigned to multiple requests that follow the same chain(s). Verify this before creating the tickets.)
  • Update the GitLab issue, mentioning the ticket(s).
  • Wait for approval in the weekly MccM meeting.