CMS EDAnalyzers, python configurations, and submission tools for performing gen-level studies "on the fly" by analyzing events as they are generated and then discarding them

The QCDAnalyzer class looks at collections of GenParticles and GenJets in each event to produce spectra of particles, charged particles, postitively charged particles, and jets. It also matches particles with the
most energetic jet within a given radius to analyze the fragmentation of the GenJets. Particles may be selected based on their species, and jets on their flavor. Note the jet flavor identification is currently not working in PYTHIA8.

To run a small 100 event test:

scram p CMSSW CMSSW_7_3_1
cd CMSSW_7_3_1/src
cmsenv

mkdir Appeltel
cd Appeltel
git clone https://github.com/appeltel/GenOnTheFly.git
cd GenOnTheFly
scram b
cd test 
cmsRun anaQCD_PYTHIA8_cfg.py

To run a set of 100k events each in 10 different "pt-hat" ranges, using PYTHIA8 Tune 4C, run the script test/submitPYTHIA8_QCDana.sh

The analyzer output from different pt-hat ranges can be combined using the ROOT macro makeCombinedPtHatSample.C which takes the cross sections and input files as arguments, and weights all of the histograms appropriately. An example usage of this macro is test/examplePtHatCombination.C.