Kalanand's July 2013 Log
FastSimulation/InSituPileUpProducer to add pile up efficiently
From Sridhara Dasu.
Try out this module to produce your own events with large pile up,
generated in-situ using Pythia8, using CMSSW FastSimulation program.
There is no need for large pile up minbias samples ... I suggest using
Pythia8 for hard event also, but you should be able to use any
Instructions for checkout build and run a test:
scram project CMSSW CMSSW_5_3_10_patch2
cvs co -d InSituPileUpProducer UserCode/dasu/InSituPileUpProducer
cmsRun InSituPileUpProducer_cfg.py >& PU140.log&
The test produced 100 Z->mu+mu- events with average PU = 140 at 5 Hz on
an AMD Opteron(tm) Processor 6176 (just an ordinary box
Good thing is that you get AODSIM ... the objects that you really want
for running existing analyses. Of course, people need the upgrade
geometries in FastSimulation for this to be truly useful for long term.
It will work nicely for 2015-2017 studies with "existing" detector.
Pdf Uncertainty Estimation: recipe from Juan Alcaraz
a) The PDF4LHC prescription is explained at
(look at the NLO part and ignore the αS additional
discussions, which is peanuts compared to the bulk of the error).
I would use at present CT10, MSTW08 and NNPDF21.
You can even use the NNLO versions of them if you like
(but I do not expect that this will decrease your uncertainties).
b) Some code for reweighiting on AODSIM formats can be found in
the CMSSW package
But you'll likely need to install the LHAPDF libraries locally
(and do not run this over GRID: you may fail dramatically).
Look also at:
for instructions and warnings. It may even be outdated for the newset versions, I do not know.
c) Finally, I even recommend to go outside CMSSW if you have all the PDFInfo information
in ntuples. I am attaching a piece of code that shows how to reweight in a simple way each PDF member.
You always need to install locally the LHAPDF libraries in any case.
Go to June's log
Last modified: Thu June 18 10:07:35 CST 2013