CMSSW code to generate babies (small flat ntuples) from MINIAOD

• Code setup
• Adding new branches
• Getting an flist
• Conventions in babymaker

export SCRAM_ARCH=slc6_amd64_gcc700
cmsrel CMSSW_10_2_6
cd CMSSW_10_2_6/src
cmsenv
git cms-init
git cms-merge-topic lathomas:L1Prefiring_10_2_6                         # only if 2016 MC or 2017 MC
git cms-addpkg RecoMET/METFilters                                       # only if 2017 data/MC or 2018 data/MC
git cms-merge-topic cms-met:METFixEE2017_949_v2_backport_to_102X        # only if 2017 data/MC
scram b
git clone git@github.com:richstu/babymaker
cd babymaker
./compile.sh

To add new branches to the tree, you first create the new branch in babymaker/variables/full where the type and name are specified. The code in babymaker/bmaker/genfiles/src/generate_baby.cxx automatically generates the files

babymaker/bmaker/interface/baby_base.hh
babymaker/bmaker/interface/baby_full.hh
babymaker/bmaker/src/baby_base.cc
babymaker/bmaker/src/baby_full.cc

which have the c++ code that defines the class baby_full with the tree, all the branches, automatic vector clearing in the baby_full::Fill method, and other useful functions.

The branches are filled in the bmaker_full::analyze method in babymaker/bmaker/plugins/bmaker_full.cc. Functions that define physics quantities, like isolation or electron ID, are defined in babymaker/bmaker/src/*_tools.cc.

See bmaker/genfiles/README.md for detailed instructions.

In order to homogenize the code and know what to expect, we try to follow these conventions in the development of babymaker:

• Branch names use all lower case letters. If words must be separated, use an underscore, e.g. met_phi
• File names use all lower case letters. If words must be separated, use an underscore, e.g. lepton_tools.cc
• Function names follow the standard CMSSW convention, that is, first word all lower case, and first letter of subsequent words in upper case. e.g. bmaker_full::writeFatJets
• Product names (e.g. "slimmedElectrons") are only defined in bmaker_full::analize or in babymaker/bmaker/python/bmaker_full_cfg.py.
• As much as possible, physics definitions go in the corresponding src/*_tools.cc file, e.g. lepton ID goes in src/lepton_tools.cc. They should not be part of plugins/bmaker_full.cc so that when/if we move to having various baby definitions in parallel, for which the code is setup, all babies would use common definitions.