doc/hackathon/rf702__efficiencyfit__2D_8py.html

import ROOT


flat = False

# Construct efficiency function e(x,y)

# -----------------------------------------------------------------------


# Declare variables x,mean, with associated name, title, value and allowed

# range

x = ROOT.RooRealVar("x", "x", -10, 10)

y = ROOT.RooRealVar("y", "y", -10, 10)


# Efficiency function eff(x;a,b)

ax = ROOT.RooRealVar("ax", "ay", 0.6, 0, 1)

bx = ROOT.RooRealVar("bx", "by", 5)

cx = ROOT.RooRealVar("cx", "cy", -1, -10, 10)


ay = ROOT.RooRealVar("ay", "ay", 0.2, 0, 1)

by = ROOT.RooRealVar("by", "by", 5)

cy = ROOT.RooRealVar("cy", "cy", -1, -10, 10)


effFunc = ROOT.RooFormulaVar(

    "effFunc", "((1-ax)+ax*cos((x-cx)/bx))*((1-ay)+ay*cos((y-cy)/by))", [ax, bx, cx, x, ay, by, cy, y]

)


# Acceptance state cut (1 or 0)

cut = ROOT.RooCategory("cut", "cutr", {"accept": 1, "reject": 0})


# Construct conditional efficiency pdf E(cut|x,y)

# ---------------------------------------------------------------------------------------------


# Construct efficiency pdf eff(cut|x)

effPdf = ROOT.RooEfficiency("effPdf", "effPdf", effFunc, cut, "accept")


# Generate data(x,y,cut) from a toy model

# -------------------------------------------------------------------------------


# Construct global shape pdf shape(x) and product model(x,cut) = eff(cut|x)*shape(x)

# (These are _only_ needed to generate some toy MC here to be used later)

shapePdfX = ROOT.RooPolynomial("shapePdfX", "shapePdfX", x, [0 if flat else -0.095])

shapePdfY = ROOT.RooPolynomial("shapePdfY", "shapePdfY", y, [0 if flat else +0.095])

shapePdf = ROOT.RooProdPdf("shapePdf", "shapePdf", [shapePdfX, shapePdfY])

model = ROOT.RooProdPdf("model", "model", {shapePdf}, Conditional=({effPdf}, {cut}))


# Generate some toy data from model

data = model.generate({x, y, cut}, 10000)


# Fit conditional efficiency pdf to data

# --------------------------------------------------------------------------


# Fit conditional efficiency pdf to data

effPdf.fitTo(data, ConditionalObservables={x, y}, PrintLevel=-1)


# Plot fitted, data efficiency

# --------------------------------------------------------


# Make 2D histograms of all data, data and efficiency function

hh_data_all = data.createHistogram("hh_data_all", x, Binning=8, YVar=dict(var=y, Binning=8))

hh_data_sel = data.createHistogram("hh_data_sel", x, Binning=8, YVar=dict(var=y, Binning=8), Cut="cut==cut::accept")

hh_eff = effFunc.createHistogram("hh_eff", x, Binning=50, YVar=dict(var=y, Binning=50))


# Some adjustsment for good visualization

hh_data_all.SetMinimum(0)

hh_data_sel.SetMinimum(0)

hh_eff.SetMinimum(0)

hh_eff.SetLineColor("kBlue")


# Draw all frames on a canvas

ca = ROOT.TCanvas("rf702_efficiency_2D", "rf702_efficiency_2D", 1200, 400)

ca.Divide(3)

ca.cd(1)

ROOT.gPad.SetLeftMargin(0.15)

hh_data_all.GetZaxis().SetTitleOffset(1.8)

hh_data_all.Draw("lego")

ca.cd(2)

ROOT.gPad.SetLeftMargin(0.15)

hh_data_sel.GetZaxis().SetTitleOffset(1.8)

hh_data_sel.Draw("lego")

ca.cd(3)

ROOT.gPad.SetLeftMargin(0.15)

hh_eff.GetZaxis().SetTitleOffset(1.8)

hh_eff.Draw("surf")


ca.SaveAs("rf702_efficiency_2D.png")