ALPGEN Production in 31X

Goals

• Test the Alpgen Prouduction Workflow in CMSSW 3_1_X

Modus Operandi

1. Creation of ASCII LHE files outside the CMS framework
2. Publication of corresponding articles into MCDB (http://mcdb.cern.ch)
3. Execution of CMSSW jobs (at CERN)for retrieving the files, translating the ASCII LHE files into EDM LHE files and publishing them to DBS
4. Deployment of the files to the T2s for production.

• The responsabilty of the Generator group is for steps 1 and 2. DMWM will execute the jobs for accomplishing 3 and 4.
• Preferred file size from DataOps: 1-2 GB, ~ 1M events in the same LHE file.

Action Items

• Try to generate large (1M) LHE fils and upload to MCDB.
  • 50 jobs of 2000000 events each, ttbar+1 jet, 40 GeV, should produce some 900K ttbar+1j unw events. Submitted to Condor.
  • Each job takes in average 3min 15sec!
  • Efficiency: 0.91% (average 18200 events obtained per job)
  • If I just concatenate the .unw files, AlpgenSource does not care... does it? No it doesn't =D

-- ThiagoTomei - 18 May 2009

• Questions:

1. What to do with the cross-sections and the luminosity, when concatening different files?
   • Sum the luminosities, average the cross-sections, average/sqrt(N) the errors?
2. What is the workflow? For minimum startup conditions:
   1. ALPGEN Standalone + Condor --> generate many .wgt files, unweight them to many .unw files
   2. Script to concatenate all .unw files, write a single, unified _unw.par file, and write a .tar.gz file containing ALL the .wgt and .par files.
   3. cmsRun jobs + LHEWriter --> generate a single, large .lhe file
   4. upload to MCDB --> there is a Perl script from http://mcdb.cern.ch for that, but does it work from outside CERN? It uses SRM to access CASTOR.
   5. Coach somebody to test the following parts (MCDBSource, split and merge).

1. UPDATE: managed to run the full chain up MCDB source (article 239). * But there is a problem, CMSSW_3_1_X is not yet installed at SPRACE.
2. UPDATE: things that should be in the test suite:
   • Check if grids are correct (maybe not needed now, for we are using LHE files?)
   • Check if split and merge works.

-- ThiagoTomei - 22 May 2009