def addHistToTGraphPoisson(self, h, g, w=1.):
for i in range(0, g.GetN()):
# shifted by +1, i.e. over/underflow
err = h.GetBinError(i + 1)
y = h.GetBinContent(i + 1)
binWidth = h.GetBinWidth(i + 1)
# From https://twiki.cern.ch/twiki/bin/view/CMS/PoissonErrorBars
alpha = 1. - 0.6827
n = int(
round(y * binWidth /
w)) # Round is necessary due to, well, rounding errors
l = Math.gamma_quantile(alpha / 2., n, 1.) if n != 0. else 0.
u = Math.gamma_quantile_c(alpha, n + 1, 1) if n != 0. else 0.
g.SetPointEYlow(
i,
math.sqrt(((n - l) / binWidth * w)**2 + g.GetErrorYlow(i)**2))
g.SetPointEYhigh(
i,
math.sqrt(((u - n) / binWidth * w)**2 + g.GetErrorYhigh(i)**2))
gx = Double(0.)
gy = Double(0.)
g.GetPoint(i, gx, gy)
g.SetPoint(i, gx, y + gy)
def __init__( self, process_list, sf = None, df = None ):
self.__processes = process_list
if sf and df:
self.__sf = sf
self.__df = df
alpha = 1 - 0.6827
self.__sfCRGraph = TGraphAsymmErrors(self.__sf)
self.__dfCRGraph = TGraphAsymmErrors(self.__df)
for g in [self.__sfCRGraph, self.__dfCRGraph]:
for i in range(g.GetN()):
N = g.GetY()[i]
LowErr = 0 if N == 0 else Math.gamma_quantile(alpha/2, N, 1.)
UpErr = Math.gamma_quantile_c(alpha/2, N+1, 1.) # recommended by StatComm (1.8)
# Math.gamma_quantile_c(alpha, N+1, 1.) # gives 1.2, strictly 68% one-sided
g.SetPointEYlow(i, N-LowErr)
g.SetPointEYhigh(i, UpErr-N)
for p in self.__processes:
if p.name() in ['nonpromptSF', 'nonpromptDF']:
nom, low, high = [], [], []
for ib in range(p.nominal().GetXaxis().GetNbins()):
if p.name() in ['nonpromptDF']: hnp = self.__dfCRGraph
else: hnp = self.__sfCRGraph
npcr = hnp.GetY()[ib]
npcrErrLow = hnp.GetEYlow()[ib]
npcrErrHigh = hnp.GetEYhigh()[ib]
np = p.nominal().GetBinContent(ib+1)
npErr = p.nominal().GetBinError(ib+1)
alpha = np/npcr if npcr > 0 else npErr
nom.append(npcr*alpha)
low.append(npcrErrLow*alpha)
high.append(npcrErrHigh*alpha)
hnom = p.nominal().Clone()
for ib in range(hnom.GetXaxis().GetNbins()):
hnom.SetBinContent(ib+1, nom[ib])
npGraph = TGraphAsymmErrors(hnom)
for ib in range(hnom.GetXaxis().GetNbins()):
npGraph.SetPointEYlow(ib, low[ib])
npGraph.SetPointEYhigh(ib, high[ib])
if p.name() in ['nonpromptDF']:
self.__dfGraph = npGraph
else:
self.__sfGraph = npGraph
self.__uncertainties = set()
for p in self.__processes:
self.__uncertainties = self.__uncertainties.union( set( p.uncertaintySources() ) )
def calculatePoissonErrors(n, confidenceInterval=0.6827):
## Calcultes the Poisson error for a given numer
# n number of entries
# confidenceInterval probability covered inside the error band
from ROOT import Math
n = round(n)
invIntegral = (1. - confidenceInterval) / 2.
lo = Math.gamma_quantile(invIntegral, n, 1.) if n != 0 else 0.
hi = Math.gamma_quantile_c(invIntegral, n + 1, 1.)
return n - lo, hi - n
def createTGraphPoisson(self, h, w=1.):
self.tfile.cd()
g = TGraphAsymmErrors(h)
for i in range(0, g.GetN()):
y = h.GetBinContent(i+1)
binWidth = h.GetBinWidth(i+1)
# From https://twiki.cern.ch/twiki/bin/view/CMS/PoissonErrorBars
alpha = 1. - 0.6827
n = int(round(y*binWidth/w)) # Round is necessary due to, well, rounding errors
l = Math.gamma_quantile(alpha/2., n, 1.) if n != 0. else 0.
u = Math.gamma_quantile_c(alpha, n+1, 1)
# print y*binWidth/w, n, y, u, l
g.SetPointEYlow(i, (n-l)/binWidth*w)
g.SetPointEYhigh(i, (u-n)/binWidth*w)
return g
def createTGraphPoisson(self, h, w=1.):
self.tfile.cd()
g = TGraphAsymmErrors(h)
for i in range(0, g.GetN()):
y = h.GetBinContent(i + 1)
binWidth = h.GetBinWidth(i + 1)
# From https://twiki.cern.ch/twiki/bin/view/CMS/PoissonErrorBars
alpha = 1. - 0.6827
n = int(
round(y * binWidth /
w)) # Round is necessary due to, well, rounding errors
l = Math.gamma_quantile(alpha / 2., n, 1.) if n != 0. else 0.
u = Math.gamma_quantile_c(alpha, n + 1, 1)
# print y*binWidth/w, n, y, u, l
g.SetPointEYlow(i, (n - l) / binWidth * w)
g.SetPointEYhigh(i, (u - n) / binWidth * w)
return g
def addHistToTGraphPoisson(self, h, g, w=1.):
for i in range(0, g.GetN()):
# shifted by +1, i.e. over/underflow
err = h.GetBinError(i+1)
y = h.GetBinContent(i+1)
binWidth = h.GetBinWidth(i+1)
# From https://twiki.cern.ch/twiki/bin/view/CMS/PoissonErrorBars
alpha = 1. - 0.6827
n = int(round(y*binWidth/w)) # Round is necessary due to, well, rounding errors
l = Math.gamma_quantile(alpha/2., n, 1.) if n != 0. else 0.
u = Math.gamma_quantile_c(alpha, n+1, 1) if n != 0. else 0.
g.SetPointEYlow(i, math.sqrt(((n-l)/binWidth*w)**2 + g.GetErrorYlow(i)**2))
g.SetPointEYhigh(i, math.sqrt(((u-n)/binWidth*w)**2 + g.GetErrorYhigh(i)**2))
gx = Double(0.)
gy = Double(0.)
g.GetPoint(i, gx, gy)
g.SetPoint(i, gx, y + gy)
Nbkg = Nqcd + Nzj + Nwt
acc = TFile("/user2/sfarry/workspaces/top/tuples/ttbar_acc.root")
A = acc.Get('acc').GetVal()
A_err = acc.Get('acc_err').GetVal()
xsec = Nsig * A / (totaleff * L )
from math import floor
#poisson uncertainties
alpha = 1 - 0.68268942
Nwt_err_lo = Nwt - Math.gamma_quantile(alpha/2.0, floor(Nwt),1)
Nzj_err_lo = Nzj - Math.gamma_quantile(alpha/2.0, floor(Nzj),1)
Nqcd_err_lo = Nqcd - Math.gamma_quantile(alpha/2.0, floor(Nqcd),1)
Nbkg_err_lo = Nbkg - Math.gamma_quantile(alpha/2.0, floor(Nbkg),1)
Nwt_err_hi = Math.gamma_quantile_c(alpha/2.0, floor(Nwt)+1,1) - Nwt
Nzj_err_hi = Math.gamma_quantile_c(alpha/2.0, floor(Nzj)+1,1) - Nzj
Nqcd_err_hi = Math.gamma_quantile_c(alpha/2.0, floor(Nqcd)+1,1) - Nqcd
Nbkg_err_hi = Math.gamma_quantile_c(alpha/2.0, floor(Nbkg)+1,1) - Nbkg
stat_err = xsec / sqrt(Nevts)
syst_err = xsec * sqrt(pow(totaleff_err / totaleff, 2) + pow(A_err / A, 2) + pow(Nbkg_err_hi/(Nevts - Nbkg),2))
lumi_err = xsec * 0.039
print "Number of selected events: %f +/- %f" %(Nevts, sqrt(Nevts))
print "Same sign background : %f + %f - %f" %(Nqcd, Nqcd_err_hi, Nqcd_err_lo)
print "Z+jets background : %f + %f - %f" %(Nzj, Nzj_err_hi, Nzj_err_lo)
print "Wt background : %f + %f - %f" %(Nwt, Nwt_err_hi, Nwt_err_lo)
print "Background Events : %f + %f - %f" %(Nbkg, Nbkg_err_hi, Nbkg_err_lo)
print "Lumi : %f +/- %f" %(L, L_err)
