File indexing completed on 2024-04-06 12:23:28
0001 from __future__ import print_function
0002 from ROOT import TH1F, TH2F, TFile
0003
0004
0005 class EnergyCorrector( object ):
0006 """Generic energy corrector"""
0007
0008 def __init__(self, fnam, histnam='h_cor'):
0009 """
0010 fnam is a root file containing a 1D histogram giving
0011 the correction factor as a function of eta.
0012 """
0013 self.file = TFile(fnam)
0014 if self.file.IsZombie():
0015 raise ValueError(fnam+' cannot be opened')
0016 self.hist = self.file.Get(histnam)
0017 if self.hist==None:
0018 raise ValueError('{h} cannot be found in {f}'.format(h=histnam,
0019 f=fnam))
0020
0021
0022 def correct_p4(self, p4):
0023 """
0024 returns the corrected 4-momentum.
0025 The 4 momentum is expected to behave as the one of the Candidate class
0026 """
0027 eta = p4.eta()
0028 pt = p4.pt()
0029 return pt*self.correction_factor(pt, eta)
0030
0031 def correction_factor(self, pt, eta):
0032 """
0033 returns the correction factor.
0034 takes also pt as this class could be generalized for a 2D calibration.
0035 """
0036 etabin = self.hist.FindBin(eta)
0037 shift = self.hist.GetBinContent(etabin)/100.
0038 return shift
0039
0040
0041 if __name__ == '__main__':
0042
0043 import sys
0044 c = JetEnergyCorrector( sys.argv[1] )
0045 etas = [-5, -4.5, -4, -3, -2.5, -2, -1, 0, 1, 2, 2.5, 3, 4, 4.5, 5]
0046 pt = 20.
0047 print(pt)
0048 for eta in etas:
0049 print(eta, c.correction_factor(pt, eta))
0050
