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MC Generation, Simulation and Reconstruction

Step 3: Reconstructing events

In this step we are going to do the reconstruction. There are two options, A)Full reconstruction or B)AOD only

1) Use cmsDriver.py to make a executable python file

If you wish to have access to the full RECO event content use the following commands:

cmsDriver.py step3 \
--step RAW2DIGI,L1Reco,RECO \
--conditions auto:mc \
--pileup NoPileUp \
--customise Configuration/GlobalRuns/reco_TLR_42X.customisePPMC \
--datatier GEN-SIM-RECO \
--eventcontent RECOSIM \
--no_exec

If you wish to have only the AOD event content then enter the following commands:

cmsDriver.py step3 \
--step RAW2DIGI,L1Reco,RECO \
--conditions auto:mc \
--pileup NoPileUp \
--customise Configuration/GlobalRuns/reco_TLR_42X.customisePPMC \
--datatier GEN-SIM-RECO \
--eventcontent AODSIM \
--no_exec

After you do that you will get some messages and then a new file will be produced in the directory you're working with with "step3_*blah*".py. Inside this file you will find a place to:

a) Change the numbers of events (this can be done at the cmsDriver.py stage, but I don't see the reason why)
b) Change the input file name(s) and location(s)
c) Chage the output file name and location

2) Running a generation job with cmsRun

I suggest you do all three and run a small job (100 evts) using the command:

cmsRun "step3_*blah*".py

That is it, you are done. The only thing left to do is to ntuplize the output.
N.B. You cannot do the reconstruction step in the same directory in which cfA ntupling is done!!! The ntuple sets certain parameters which the reconstruction doesn't like and everything comes crashing down around you!

Christopher Edward Justus

Last modified: Tue May 18 14:15:15 PDT 2010