This page contains instructions and examples of a way to extract information from a CMS root file type EDM. The root files contain collections of physical objects arranged within this structure, these objects can be: electrons, muons, photons, jets, tracks, etc. Scientific research requires specific information to obtain good results. This information can be extracted from an EDM file by creating an EDAnalyzer.
The instructions to write your own EDAnalyzer are here.
In the code there are several comments explaining the logic that follows, also, some twiki links were added to expand the knowledge on the subject.
- Install CERN virtual machine from the CMS open data website.
- Set up your enviroment
- Create a project area:
cmsrel CMSSW_5_3_32
- Change to the CMSSW_5_3_32/src/ directory:
cd CMSSW_5_3_32/src/
- Then, run the following command to create the CMS runtime variables:
cmsenv
- Obtain the code from git:
git clone git://github.com/cms-legacydata-analyses/PhysObjectExtractorTool.git
cd PhysObjectExtractorTool
- Compile everything:
cd PhysObjectExtractor
scram b
- Make a soft link to the python configuration file
ln -s python/physicsobjectsinfo_cfg.py .
- Make symbolic links to the conditions database: (trigger analizer)
ln -sf /cvmfs/cms-opendata-conddb.cern.ch/FT_53_LV5_AN1_RUNA FT_53_LV5_AN1
ln -sf /cvmfs/cms-opendata-conddb.cern.ch/FT_53_LV5_AN1_RUNA.db FT_53_LV5_AN1_RUNA.db
- Run the CMSSW configuration file:
cmsRun physicsobjectsinfo_cfg.py