def get_uncertainty_graph(hnom, curve_uncert):
"""
Convert an histogram and a RooCurve
into a TGraphAsymmError
Parameters
----------
hnom: TH1F, TH1D, ...
The histogram of nominal values
curve_uncert: RooCurve
The uncertainty band around the nominal value
TODO: Improve the handling of the underflow and overflow bins
"""
graph = Graph(hnom.GetNbinsX())
for ibin in xrange(1, hnom.GetNbinsX() + 1):
uncerts = []
for ip in xrange(3, curve_uncert.GetN() - 3):
x, y = ROOT.Double(0.), ROOT.Double(0.)
curve_uncert.GetPoint(ip, x, y)
if hnom.GetBinLowEdge(ibin) <= x < hnom.GetBinLowEdge(ibin + 1):
uncerts.append(y)
log.debug('{0}, bin {1}: {2}'.format(hnom.name, ibin, uncerts))
low, high = min(uncerts), max(uncerts)
bin_center = 0.5 * (hnom.GetBinLowEdge(ibin + 1) +
hnom.GetBinLowEdge(ibin))
e_x_low = bin_center - hnom.GetBinLowEdge(ibin)
e_x_high = hnom.GetBinLowEdge(ibin + 1) - bin_center
bin_content = hnom.GetBinContent(ibin)
e_y_low = hnom.GetBinContent(ibin) - low
e_y_high = high - hnom.GetBinContent(ibin)
graph.SetPoint(ibin - 1, bin_center, bin_content)
graph.SetPointError(ibin - 1, e_x_low, e_x_high, e_y_low, e_y_high)
return graph
def UncertGraph(hnom, curve_uncert):
"""
Convert an histogram and a RooCurve
into a TGraphAsymmError
Parameters
----------
hnom: TH1F, TH1D,...
The histogram of nominal values
curve_uncert: RooCurve
The uncertainty band around the nominal value
curve_uncert: RooCurve
TODO: Improve the handling of the underflow and overflow bins
"""
graph = Graph(hnom.GetNbinsX())
# ---------------------------------------------
for ibin in xrange(1, hnom.GetNbinsX() + 1):
uncerts = []
for ip in xrange(3, curve_uncert.GetN() - 3):
x, y = ROOT.Double(0.), ROOT.Double(0.)
curve_uncert.GetPoint(ip, x, y)
if int(x) == int(hnom.GetBinLowEdge(ibin)):
uncerts.append(y)
uncerts.sort()
log.info('{0}: {1}'.format(hnom.name, uncerts))
if len(uncerts) != 2:
for val in uncerts:
if val in uncerts:
uncerts.remove(val)
if len(uncerts) != 2:
raise RuntimeError(
'Need exactly two error values and got {0}'.format(uncerts))
bin_center = 0.5 * (hnom.GetBinLowEdge(ibin + 1) +
hnom.GetBinLowEdge(ibin))
e_x_low = bin_center - hnom.GetBinLowEdge(ibin)
e_x_high = hnom.GetBinLowEdge(ibin + 1) - bin_center
bin_content = hnom.GetBinContent(ibin)
e_y_low = hnom.GetBinContent(ibin) - uncerts[0]
e_y_high = uncerts[1] - hnom.GetBinContent(ibin)
graph.SetPoint(ibin - 1, bin_center, bin_content)
graph.SetPointError(ibin - 1, e_x_low, e_x_high, e_y_low, e_y_high)
# ---------------------------------------------
return graph
