PyAlgorithmExample.PyAlgorithmExample Class Reference

The example algorithm. More...

Inheritance diagram for PyAlgorithmExample.PyAlgorithmExample:

Collaboration diagram for PyAlgorithmExample.PyAlgorithmExample:

Public Member Functions
def	__init__ (self, name, args)
def	execute (self)
def	get_electrons (self)
def	get_muons (self)
def	get_taujets (self)
def	get_met (self)
def	find_zll (self, llist, h)
def	find_ztt (self, parts, met, zll, h)
def	find_hzz (self, candlist, h)

Public Attributes
	args
	h

Detailed Description

The example algorithm.

We derive from PyAlgorithm, which means that this is a Gaudi algorithm in every sense.

Definition at line 343 of file PyAlgorithmExample.py.

Constructor & Destructor Documentation

__init__()

def PyAlgorithmExample.PyAlgorithmExample.__init__	(		self,
			name,
			args
	)

Definition at line 346 of file PyAlgorithmExample.py.

    def __init__ (self, name, args):
        # Initialze base class.
        PyAlgorithm.__init__ (self, name)
 
        # Save the arguments.
        self.args = args
 
        # Make the class to hold the histograms.
        # We stick them in a separate instance to that they can be easily
        # saved via root_pickle.
        h = Holder()
        self.h = h
 
        # Create histograms.
        h.ele0 = Partlisthists_Ele ('ele0')
        h.ele1 = Partlisthists_Ele ('ele1')
        h.ele2 = Partlisthists_Ele ('ele2')
 
        h.muo0 = Partlisthists_Muo ('muo0')
        h.muo1 = Partlisthists_Muo ('muo1')
 
        h.taujet0 = Partlisthists_Taujet ('taujet0')
        h.taujet1 = Partlisthists_Taujet ('taujet1')
 
        h.metx = mybook ("metx", 100, 0, 500*GeV)
        h.mety = mybook ("mety", 100, 0, 500*GeV)
        h.met  = mybook ("met",  100, 0, 500*GeV)
 
        h.zee = [Partlisthists_Z('zee0'), Partlisthists_Z('zee1')]
        h.zmm = [Partlisthists_Z('zmm0'), Partlisthists_Z('zmm1')]
        h.zll = Partlisthists_Z('zll')
 
        h.ztt = [Partlisthists_Z('ztt0'), Partlisthists_Z('ztt1')]
 
        h.hzz = [Partlisthists_Z ('hzz0', m_max=500*GeV),
                Partlisthists_Z ('hzz1', m_max=500*GeV)]
 
        h.ncand = mybook ("ncand", 10, 0, 10)
 
        # Initialize event counters.
        h.n_in = 0
        h.n_met_cut = 0
        h.n_zll_cut = 0
        h.n_4parts_cut = 0
        h.n_cand_cut = 0
        h.n_hzz_cut = 0
        return
 
 

Member Function Documentation

execute()

def PyAlgorithmExample.PyAlgorithmExample.execute

(

self

)

Definition at line 396 of file PyAlgorithmExample.py.

    def execute (self):
        args = self.args
        h = self.h
 
        # Get particles from storegate.
        eles = self.get_electrons()
        muos = self.get_muons()
        taujets = self.get_taujets()
        met = self.get_met()
 
        # Find Z->ll decays.
        # Find them Z->ee and Z->mm separately, then combine the lists,
        # and then fill histograms from the combined list.
        zees = self.find_zll (eles, h.zee)
        zmms = self.find_zll (muos, h.zmm)
        zlls = zees + zmms
        h.zll.fill (zlls)
 
        # Make preliminary cuts.
        # Count the events passing the cuts.
        h.n_in += 1
 
        # Missing et cut.
        if met.pt < args.met_cut: return 1
        h.n_met_cut += 1
 
        # Must find at least one Z->ll.
        if len (zlls) == 0: return 1
        h.n_zll_cut += 1
 
        # Need at least four final-state particles.
        if len (eles) + len (muos) + len (taujets) < 4: return 1
        h.n_4parts_cut += 1
 
        # Combine all final-state particles into a single list.
        # We'll use this to search for Z->tautau decays.
        parts = eles + muos + taujets
 
        # For each Z->ll decay, we look for Z->tautau decays.
        # In general, for a given Z->ll decay, we may have 0, 1, or more
        # Z->tautau candidates.  In CANDLIST, we make a list of all the
        # candiate (zll, ztt) decays we find.
        candlist = []
 
        # Loop over Z->ll candidates.
        for z in zlls:
            # Search for Z->tautau candidates, given a specific Z->ll
            # candidate.
            ztts = self.find_ztt (parts, met, z, h.ztt)
            # Append all of our candidates to the list.
            for z2 in ztts: candlist.append ((z, z2))
 
        # Now require that we find at least one
        # Z->ll, Z->tautau pair.
        if len (candlist) == 0: return 1
        h.n_cand_cut += 1
        h.ncand.Fill (len (candlist))
 
        # Construct the H->ZZ candidates.
        hzzs = self.find_hzz (candlist, h.hzz)
        h.n_hzz_cut += 1
        return 1
 
 

find_hzz()

def PyAlgorithmExample.PyAlgorithmExample.find_hzz	(		self,
			candlist,
			h
	)

Definition at line 628 of file PyAlgorithmExample.py.

    def find_hzz (self, candlist, h):
        # For each candidate pair, construct a higgs object.
        # Reuse the Z class for this.
        # Then fill histograms.
        hzzs = [Z (zll, ztt, PDG.Higgs0) for (zll, ztt) in candlist]
        h[0].fill (hzzs)
 
        # Make a DR cut and fill histograms again.
        def select (hg):
            return hg.dr() < args.hzz_deltar_cut
        hzzs = [hg for hg in hzzs if select (hg)]
        h[1].fill (hzzs)
 
        # Return the candidate list.
        return hzzs

find_zll()

def PyAlgorithmExample.PyAlgorithmExample.find_zll	(		self,
			llist,
			h
	)

Definition at line 557 of file PyAlgorithmExample.py.

    def find_zll (self, llist, h):
        args = self.args
 
        # Make a candidate Z particle for each opposite-sign lepton pair
        # combination and fill histograms.
        zlist = [Z (l1, l2) for (l1,l2) in combo.combinations (llist, 2)
                 if l1.charge()*l2.charge() < 0]
        h[0].fill (zlist)
 
        # Now filter candiates, applying a mass window and DR cut.
        # Then histogram the results.
        def select (z):
            return (z.dr() < args.zll_deltar_cut and
                    abs(z.m() - MZ) < args.zll_deltam_cut)
        zlist = [z for z in zlist if select (z)]
        h[1].fill (zlist)
        return zlist
 
 

find_ztt()

def PyAlgorithmExample.PyAlgorithmExample.find_ztt	(		self,
			parts,
			met,
			zll,
			h
	)

Definition at line 583 of file PyAlgorithmExample.py.

    def find_ztt (self, parts, met, zll, h):
        args = self.args
 
        # Remove particles that were used in the Z->ll decay.
        parts = [p for p in parts if p not in zll]
 
        # List of candidates we're building.
        zlist = []
 
        # Loop over all pairs of remaining particles.
        for (l1, l2) in combo.combinations (parts, 2):
            # Use only oppositely-charged pairs.
            # Does this work for tau jets?
            if l1.charge() * l2.charge() > 0: continue
 
            # Build the candidate Z.
            z = Z (l1, l2)
 
            # Calculate the neutrino momenta, and add them to the Z candidate.
            (nu1, nu2) = neutrinos_from_colinear_approximation (l1, l2,
                                                                met.etx(),
                                                                met.ety())
            z.add (nu1)
            z.add (nu2)
            zlist.append (z)
 
        # Fill histograms from the initial set of candidates.
        h[0].fill (zlist)
 
        # Make mass and dr cuts and fill another set of histograms.
        def select (z):
            return (z.dr() < args.ztt_deltar_cut and
                    abs(z.m() - MZ) < args.ztt_deltam_cut)
        zlist = [z for z in zlist if select (z)]
        h[1].fill (zlist)
 
        # Return candidates.
        return zlist
 
 

get_electrons()

def PyAlgorithmExample.PyAlgorithmExample.get_electrons

(

self

)

Definition at line 463 of file PyAlgorithmExample.py.

    def get_electrons (self):
        args = self.args
        h = self.h
 
        # Helper function: apply particle ID cuts to candidate E.
        def track_select (e):
            if not fulldata(e): return 1
            return e.hasTrack() and e.isEM()%16 == 0
 
        # Helper function: apply kinematic cuts to candidate E.
        def select (e):
            return e.pt() > args.ele_pt_cut and abs(e.eta()) < args.ele_eta_cut
 
        # Fetch electrons from storegate, apply particle ID cuts,
        # then kinematic cuts, then return the results.  Fill histograms
        # after each step.
        eles = PyParticleTools.getElectrons (args.electron_container)
        h.ele0.fill (eles)
        eles = [e for e in eles if track_select (e)]
        h.ele1.fill (eles)
        eles = [e for e in eles if select (e)]
        h.ele2.fill (eles)
        return eles
    
 

get_met()

def PyAlgorithmExample.PyAlgorithmExample.get_met

(

self

)

Definition at line 540 of file PyAlgorithmExample.py.

    def get_met (self):
        args = self.args
        h = self.h
        met = PyParticleTools.getMissingET (args.met_container)
        h.metx.Fill (met.etx())
        h.mety.Fill (met.ety())
        met.pt = math.hypot (met.etx(), met.ety())
        h.met.Fill (met.pt)
        return met
 
 

get_muons()

def PyAlgorithmExample.PyAlgorithmExample.get_muons

(

self

)

Definition at line 491 of file PyAlgorithmExample.py.

    def get_muons (self):
        args = self.args
        h = self.h
 
        # Helper function: apply kinematic cuts to candidate M.
        def select (m):
            return m.pt() > args.muo_pt_cut and abs(m.eta()) < args.muo_eta_cut
 
        # Fetch muons from storegate, apply 
        # kinematic cuts, then return the results.  Fill histograms
        # after each step.
        muos = PyParticleTools.getMuons (args.muon_container)
        h.muo0.fill (muos)
        muos = [m for m in muos if select (m)]
        h.muo1.fill (muos)
        return muos
    
 

get_taujets()

def PyAlgorithmExample.PyAlgorithmExample.get_taujets

(

self

)

Definition at line 512 of file PyAlgorithmExample.py.

    def get_taujets (self):
        args = self.args
        h = self.h
 
        # Helper function: apply quality and kinematic cuts to candidate T.
        def select (t):
            if (t.pt() < args.taujet_pt_cut or
                abs(t.eta()) > args.taujet_eta_cut):
                return 0
            if not fulldata(t): return 1
            if t.likelihood() < args.taujet_likeli_cut: return 0
            emfrac = t.etEM() / (t.etEM() + t.etHad())
            if emfrac > args.taujet_max_emfrac: return 0
            return 1
 
        # Fetch tau jets from storegate, apply quality and kinematic cuts,
        # then return the results.  Fill histograms before and after
        # the cuts.
        taujets = PyParticleTools.getTauJets (args.taujet_container)
        h.taujet0.fill (taujets)
        taujets = [t for t in taujets if select (t)]
        h.taujet1.fill (taujets)
        return taujets
    
 

Member Data Documentation

args

PyAlgorithmExample.PyAlgorithmExample.args

Definition at line 351 of file PyAlgorithmExample.py.

h

PyAlgorithmExample.PyAlgorithmExample.h

Definition at line 357 of file PyAlgorithmExample.py.

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The documentation for this class was generated from the following file:

• PyAlgorithmExample.py