manTree SFrame PileUpTool instructions

Installation

Start with a clean shell & setup sframe.

Then you need to checkout the package:

svn co svn+ssh://svn.cern.ch/reps/atlasoff/PhysicsAnalysis/AnalysisCommon/PileupReweighting/trunk PileupReweighting

You will need myusername@svn.cern.ch if your cern username is different to your manchester one. If you want to take a tagged version, e.g. 00-00-09, the command is like:

cd $SFRAME_DIR
svn co svn+ssh://svn.cern.ch/reps/atlasoff/PhysicsAnalysis/AnalysisCommon/PileupReweighting/tags/PileupReweighting-00-00-09 PileupReweighting

Now you need to compile (after patching the makefile):

cd PileupReweighting/cmt
gmake -f Makefile.Standalone

This generates the shared library: PileupReweighting/StandAlone/PileupReweightingLib.so

Now make a soft link of library PileupReweightingLib.so to your SFrame library folder

ln -s $SFRAME_DIR/PileupReweighting/StandAlone/PileupReweightingLib.so $SFRAME_DIR/lib

What The tool does

More details can be found here. But the tool compares the average number of interactions per bunch crossing (mu) for the MC sample (mc10a (r2215_r2260)) to what we see in data.

* AvintprxperiodD:

• Mu_mc10a.png:
  

Adding PileUpWeight to SFrame analysis code

This code is dealt with by topUtils. You need to check:

• root file in topObjectSel is upto date and MC root file is correct. Latest files can be found http://atlas.web.cern.ch/Atlas/GROUPS/DATAPREPARATION/InteractionsperCrossing/.

The following extract is from TobObjectSel.cxx

m_tPileUp = new Root::TPileupReweighting( (((std::string)"T")+"Pileup").c_str() );
int isGood = m_tPileUp->initialize( sframedir + "/topUtils/data/PileupMu/ilumicalc_histograms_EF_mu18_178044-180242.root",
                                      "avgintperbx",
                                      sframedir+ "/topUtils/data/PileupMu/mu_mc10a.root",
                                      "mu_mc10a");

Since Mc10a mu is stored in eventinfo class as LumiBlock(). To use this In your analysis code when running on MC do something like:

float mu = (float)m_evinfo->LumiBlock();
const double pileupEventWeight = m_object_sel->getPileUpWeight(mu);
weight*= pileupEventWeight;

Add the library to the config XML file topSel/config/TopSingleEle_config.xml

<JobConfiguration JobName="TopSingleEleJob" OutputLevel="INFO">
  <Library Name="PileupReweightingLib"/>
  

-- JohnAlmond - 05-May-2011