mgprod

This code is meant to generate Monte Carlo events using MadGraph as generator and Lobster to manage the workflow steps.

Setup

In order to setup your area, run the setup scripts located in the scripts directory.

cd lobster_workflow
./scripts/setup_cmssw.sh

This setup script is simply to make sure that the correct CMSSW releases are present when running lobster and should only have to be run once. However, please note that the script may need to be edited, depending on MC samples you are trying to produce. If the release that you need for your samples is not in the script, you will need to add it to the script and rerun, or just set up the release manually.

Introduction to producing samples

The production is split into multiple steps, each with its own corresponding lobster configuration. It is assumed that the following commands are run in the lobster_workflow directory. For information about how to use lobster, please see the lobster tutorial from February of 2021, especially the slides from the "How to Lobster" section, which provide a thorough introduction.

Make sure to activate your lobster virtual environment before trying to run any of the lobster configs (Note: This implies that you must also have already done cmsenv in an appropriate CMSSW release before activating the virtual environment).

source ~/.lobster/bin/activate

The LHE step

The first step is to produce LHE level events. The lobster config for this step is lobster_LHE_config.p. This step runs on pre-made gridpack tarballs, which were produced using the CMSSW genproductions workflow, and are located somewhere on /hadoop or in a local /afs area. The gridpacks directory can contain any number of gridpacks and can be filtered to only run over a certain sub-set of gridpacks using the whitelists in the lobster configs. For the whitelists to work, it is assumed that the gridpacks are named with the following convention: p_c_r_slc6_amd64_gcc630_CMSSW_9_3_0_tarball.tar.xz, where p,c,r correspond respectively to process, coefficient (or group) tag, and run tag.

To start production of the LHE events run:

lobster process lobster_LHE_config.py

Make sure to have a work_queue_factory running, otherwise lobster won't have any workers to process the tasks. For information about how to do this, please see the "How to Lobster" slides from the lobster tutorial mentioned above.

Note: It is very important for this step that all the workers which are used by the lobster master come from the T3 resources, otherwise the tasks will take significantly longer to finish.

The post-LHE steps

The second step runs on the LHE output produced in the first step. Any step after the LHE step can be run on either the T3 resources or the general CRC resources. There are currently several scripts with different purposes that can be run on the LHE output.

• lobster_postLHE_config.py: This script includes GEN-MAOD steps. It was designed to produce the 2017 MC used in TOP-19-001. It is not set up to produce UL MC.
• lobster_GEN_config.py: This script runs only the GEN step, and is also not set up to produce UL MC.
• lobster_postLHE_UL_config.py: This script produced UL MC. It can produce the GEN-NAOD steps, but it can be used to run only the GEN step, the GEN-MAOD steps, or the full GEN-NAOD steps by setting the STEPS variable to throughGEN, throughMAOD, or throughNAOD.

All of these lobster configs will need to be edited before you run them. You will need to edit the code to point to the input files you are interested in, and also tell the code how to name the output files. Depending on the config and your intentions, you may need to make additional edits as well.

These lobster configs feature particular run setups to try and better facilitate the transition from the first step to the second. Currently, these options are: local, mg_studies (which uses the grp_tag variable for directory naming) and ,full_production (which uses the production_tag variable for directory naming). Each of which sets up a particular and separate directory structure in your user area on /hadoop. Feel free to modify, or add your own setups, these are simply to make specifying the output from the LHE step and the input to the postLHE step as easy as possible.

Additional notes on the production of NAOD samples

The NAOD step can be run as part of the "postLHE" step as described above, or as a standalone workflow. One befit of running it as a standalone workflow (that takes as input the MAOD files produced by the postLHE step) is that it makes it cleaner and more straightforward to rerun the NAOD step. The lobster_NAOD_UL_config.py config is designed to run on the MAOD output of the lobster_postLHE_UL_config.py step to produce UL NAOD.

The following steps are for producing NAOD v9 samples (with CMSSW_10_6_26), so please be sure that you are using v9 cmsRun configs.

To generate NAOD files that include the EFT weights, we cannot use a generic CMSSW release. We need to include the code that puts the weight information into the NAOD files, so execute the following commands to set up the appropriate CMSSW release and include the necessary packages. The last three commands (the cherry-pick commands) apply the necessary changes for handling EFT samples. Note, if you are producing NAOD v8 samples (with CMSSW_10_6_19_patch2), you can just run git checkout eftfit/ULWCFit instead of the cherry-pick commands.

cmsrel CMSSW_10_6_26
cd CMSSW_10_6_26/src/
export SCRAM_ARCH=slc7_amd64_gcc700
cmsenv

git cms-addpkg PhysicsTools/NanoAOD
cd PhysicsTools/NanoAOD/
git remote add eftfit https://github.com/GonzalezFJR/cmssw.git
git fetch eftfit
git cherry-pick c0901cfc459a8d5282ebb1bc74374903d29e3eee
git cherry-pick 4068e48b02b1fcb46949b3ebeac6a7b59062c2e0
git cherry-pick 76d0a24615c2b2b3aa7333c5aed5cc7bb6a7fd1d

The NanoAOD/plugins/GenWeightsTableProducer.cc script requires WCFit and WCPoint, so clone the EFTGenReader inside of CMSSW_10_6_26/src/:

cd CMSSW_10_6_26/src/ # Or whatever cd gets you into this directory
git clone https://github.com/TopEFT/EFTGenReader.git

Finally, we will also need the NanoAODTools (described here) in order to get the script we need to merge non-EDM NAOD root files. Follow these steps to clone the repository inside of PhysicsTools:

cd CMSSW_10_6_26/src
cmsenv
git cms-init   #not really needed unless you later want to add some other cmssw stuff
git clone https://github.com/cms-nanoAOD/nanoAOD-tools.git PhysicsTools/NanoAODTools
scram b

At this point, you should have all of the necessary code in order to produce the EFT NAOD samples. Before moving on, do a scram b in the CMSSW_10_6_26/src to make sure everyting is compiled.

Finally, edit the PATH_TO_NAOD_CMSSW global variable in your lobster config to point to your new CMSSW_10_6_26 directory.