Producing Woutuple from AOD

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Producing an Ntuple from an AOD

The Ntuple that is produced from the AOD is a dump of most information contained in the AOD. The package that produces an Ntuple from the AOD contains:

  • a clone of UserAnalysis/AnalysisSkeleton and
  • a clone of AnalysisExamples/ttbar
  • the simpleTTbar class that dumps a (nearly) complete ntuple with all AOD information needed for a ttbar analysis on full simulation Monte Carlo

Step 1: Set up ATLAS release 10.0.2 software environment

Make link to Wouter's page

Step 2: Get the code

Go to the directory where you want to install the package and get the code: TTBarAnalysis.tgz

Step 3: Setting up the package

  1. Go to the directory where you want to install the package and unpack the code: tar -xzvf TTBarAnalysis.tgz The package will appear in a subdirectory named TTBarAnalysis of the chosen directory.
  2. Go to the cmt directory: cd TTBarAnalysis/cmt
  3. Execute cmt config
  4. Execute source setup.csh
  5. Build the library: gmake

Note: CMT expects that in this top directory where the package is located is in your CMTPATH. Make sure this is the case: setenv CMTPATH `pwd`:${CMTPATH}

Setp 4: Running the package (an Ntuple from an AOD)

The athena job requires as input the AOD files (also registered in the poolfilecatalogue), the names of the ParticleContainers in the AOD and the name of the output Ntuple. As an example we'll process a single file called rome.004100.recov10.T1_McAtNLO_top._00001.myaod.pool.root that is located in the directory /data/atlas/public/Rome/T1/AOD/AOD_Eric/0000/.

To process it just follow the next steps:

1) If not already done before, go to the cmt directory and execute source setup.csh

2) Go to the run directory: cd /TTBarAnalysis/run

3) Create a directory called AOD that is a link to the top directory where your AOD's are located. When handling large sets of AODs this is much more convenient than copying every AOD file to the run directory.

At NIKHEF we would do: ln -s /data/atlas/public/Rome/T1/AOD/AOD_Eric/ AOD

4) Insert the files into the pool file catalog: pool_insertFileToCatalog AOD/0000/rome.004100.recov10.T1_McAtNLO_top._00001.myaod.pool.root

5) Before launching the athena job, edit the joboptions file (

  • Set the Type of simulation (SimType, see example in joboptions file for details)
  • List your AOD file as the input AOD-file (EventSelector.InputCollections)
  • Enter the filename of the Ntuple that will be produced (NtupleSvc.Output)

6) Execute:

An Ntuple called Ntuple_file1.root is produced that can be analysed using the Analysis Skeleton.

Step 6: Extra's

Note 1:

All POOL files processed by Athena should be registered in the PoolFile Catalog. Easiest is to register ALL your AODs into the catalog: pool_insertFileToCatalog AOD/*/*AOD.pool.root

Note 2:

Check out the other wiki pages at NIKHEF on how to: Analyse the Ntuple using the AnalysisSkeleton and the Ntuple content.