MuonSegmentFilter.py

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# Copyright (C) 2002-2021 CERN for the benefit of the ATLAS collaboration
 
 
 
__doc__ = """This is a short algorithm to select events that contain one 
muon which fulfills a certain set of criteria.
"""
__version__ = "0.0.1"
__author__  = "David Lopez Mateos <David.Lopez@cern.ch>"
 
 
import AthenaPython.PyAthena as PyAthena
from AthenaPython.PyAthena import StatusCode
 
class MuonSegmentFilter( PyAthena.AthFilterAlgorithm ):
    """
    This class is a short algorithm to select events that contain some 
    number of muon segments (probably zero).
    """
 
 
 
    def __init__ ( self, name = "MuonSegmentFilter", **kw ):
        
        kw['name'] = name
        super(MuonSegmentFilter, self).__init__(**kw)
        
        
        self.muonSegmentContainerName = kw.get('muonSegmentContainers', "MooreSegments")
        self.muonSegmentContainerType = kw.get('muonSegmentContainerType', "Trk::SegmentCollection")         
        self.passAll            = kw.get('passAll', False)
        self.minNumberSegments    = kw.get('minNumberSegments', 0)
        self.maxNumberSegments    = kw.get('maxNumberSegments', 0)        
 
        #handle to storegate
        self.sgSvc = None
        self.containerNames = []
 
        return
 
    def initialize(self):
        self.msg.info( '************************************' )
        self.msg.info( '===> initialize %s...', self.name() )
        self.msg.info( 'Will apply the following cuts:' )
        self.msg.info( 'Minimum number of segments = %r',str(self.minNumberSegments) )
        self.msg.info( 'Maximum number of segments = %r',str(self.maxNumberSegments) )
 
        
        self.nProcessed            = 0
        self.nMuonSegments         = 0
        self.nEventPassed          = 0
 
        
        self.sgSvc = PyAthena.py_svc('StoreGateSvc')
        if not self.sgSvc :
            self.msg.error("could not retrieve a handle to the event store !")
            return StatusCode.Failure
 
        return StatusCode.Success
 
 
 
    def execute(self):
        self.nProcessed+=1
        self.msg.debug( '==> execute %s on %r. event...', self.name(), self.nProcessed )
        
        
        if self.passAll :
            self.msg.debug( '%s event passed because passAll is true', self.name() )
            self.setFilterPassed(True)
            return StatusCode.Success
 
        _retrieve = self.sgSvc.retrieve
 
        try :
            muSegCollection = _retrieve (self.muonSegmentContainerType, self.muonSegmentContainerName)            
        except LookupError :
            self.msg.warning('%s container not found in StoreGate ', self.muonSegmentContainerName)
   
        
        if muSegCollection.__len__() >=  self.minNumberSegments and \
             muSegCollection.__len__()<=  self.maxNumberSegments  :
            self.nEventPassed += 1
            self.msg.debug( '%s event passed', self.name() )
            self.setFilterPassed(True)
        else :
            self.msg.debug( '%s event failed', self.name() )
            self.setFilterPassed(False)
 
        return StatusCode.Success
 
 
 
    def finalize(self):
        
        import math
 
        effiNumPassed = 0.0
        effiErrNumPassed = 0.0        
        try :
            # Efficiencies
            effiNumPassed = self.nEventPassed / float(self.nProcessed)
            # Error on efficiencies, use binomial errors
            effiErrNumPassed = 100.0 * math.sqrt( effiNumPassed*(1.0 - effiNumPassed) / float(self.nProcessed) )
            effiNumPassed *= 100.0
 
        except ZeroDivisionError :
            self.msg.warning( 'Division by zero error when calculating the uncertainties on the pass efficiencies...' )
 
        
        self.msg.info( '==> finalize %s...', self.name() )
        self.msg.info( '***************************************************************' )
        self.msg.info( 'Cut-flow table of %s skimming algorithm:', self.name() )
        self.msg.info( '-------------' )
        self.msg.info( ' Number of processed events: %r', self.nProcessed )
        self.msg.info( ' Events after numberPassed %r and resulting efficiency = (%3.3f +/- %3.3f)%%', self.nEventPassed, effiNumPassed, effiErrNumPassed )
        self.msg.info( '***************************************************************' )
 
        return StatusCode.Success