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Package PhysicsTools/PythonAnalysis

CVS head for this package - Administrative privileges

Description

Examples of using CMSSW in Python. Some helper routines for startup, tab completion and shorter syntax.

Public interface

• cmstools: public interface to all modules.

Modules

• cmstools.py: prepares environment and defines some commands
• cmscompleter.py: class for tab completion
• namespaceDict.py: builds the FWLite namespace (without loading libs)
• iterators.py>: decorator for adding iterators to some containers

Unit tests and examples

• interactive use: all libraries are loaded automatically when needed. fire up the python interpreter

  python
  

  and import cmstools and ROOT:

  from PhysicsTools.PythonAnalysis import *
  from ROOT import *
  

  That's it.
• MCTruth.py: Reads gen event information and prints event number (root version)
• MCTruth2.py: Reads gen event information and prints event number (using cmstools)
• trackerHits.py: Reads sim event information and creates the files histo.root and tofhits.jpg.
  1. Prepare the environment and load the cms module:

     from PhysicsTools.PythonAnalysis.cmstools import *
     from ROOT import *
     

  2. Open ROOT file and access branch:

     events = EventTree.('simevents.root')
     

  3. Prepare histogram and loop over all events to fill it

     histo = TH1F('tofhits', 'Tof of hits', 100, -0.5, 50)
     
     for event in events:
         simHits = event.getProduct('PSimHit_r_TrackerHitsTIBLowTof.obj')
         for hit in simHits:
             histo.Fill(hit.timeOfFlight())
     

  4. Save histogram in a file:

     hFile = TFile('histo.root', 'RECREATE')
     histo.Write()
     

  5. Plot histogram as a jpg-file:

     gROOT.SetBatch()
     gROOT.SetStyle('Plain')
     
     c = TCanvas()
     histo.Draw()
     c.SaveAs('tofhits.jpg')
     

• howto.txt: short explanation

Status and planned development

Prototype.

For more details, refer to the Analysis Tools TWiki on the Software Guide.

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Last updated: 03-MAR-2007 B. Hegner

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