File indexing completed on 2024-11-25 02:29:49
0001 from ROOT import TH1F, TH2F, TFile
0002
0003
0004 class EnergyCorrector( object ):
0005 """Generic energy corrector"""
0006
0007 def __init__(self, fnam, histnam='h_cor'):
0008 """
0009 fnam is a root file containing a 1D histogram giving
0010 the correction factor as a function of eta.
0011 """
0012 self.file = TFile(fnam)
0013 if self.file.IsZombie():
0014 raise ValueError(fnam+' cannot be opened')
0015 self.hist = self.file.Get(histnam)
0016 if self.hist==None:
0017 raise ValueError('{h} cannot be found in {f}'.format(h=histnam,
0018 f=fnam))
0019
0020
0021 def correct_p4(self, p4):
0022 """
0023 returns the corrected 4-momentum.
0024 The 4 momentum is expected to behave as the one of the Candidate class
0025 """
0026 eta = p4.eta()
0027 pt = p4.pt()
0028 return pt*self.correction_factor(pt, eta)
0029
0030 def correction_factor(self, pt, eta):
0031 """
0032 returns the correction factor.
0033 takes also pt as this class could be generalized for a 2D calibration.
0034 """
0035 etabin = self.hist.FindBin(eta)
0036 shift = self.hist.GetBinContent(etabin)/100.
0037 return shift
0038
0039
0040 if __name__ == '__main__':
0041
0042 import sys
0043 c = JetEnergyCorrector( sys.argv[1] )
0044 etas = [-5, -4.5, -4, -3, -2.5, -2, -1, 0, 1, 2, 2.5, 3, 4, 4.5, 5]
0045 pt = 20.
0046 print(pt)
0047 for eta in etas:
0048 print(eta, c.correction_factor(pt, eta))
0049
