rf311_rangeplot.py

## \ingroup tutorial_roofit_main

## \notebook

## Multidimensional models: projecting pdf and data ranges in continuous observables

##

## \macro_image

## \macro_code

## \macro_output

##

## \date February 2018

## \authors Clemens Lange, Wouter Verkerke (C++ version)

import ROOT

# Create 3D pdf and data

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

# Create observables

x = ROOT.RooRealVar("x", "x", -5, 5)

y = ROOT.RooRealVar("y", "y", -5, 5)

z = ROOT.RooRealVar("z", "z", -5, 5)

# Create signal pdf gauss(x)*gauss(y)*gauss(z)

gx = ROOT.RooGaussian("gx", "gx", x, 0.0, 1.0)

gy = ROOT.RooGaussian("gy", "gy", y, 0.0, 1.0)

gz = ROOT.RooGaussian("gz", "gz", z, 0.0, 1.0)

sig = ROOT.RooProdPdf("sig", "sig", [gx, gy, gz])

# Create background pdf poly(x)*poly(y)*poly(z)

px = ROOT.RooPolynomial("px", "px", x, [-0.1, 0.004])

py = ROOT.RooPolynomial("py", "py", y, [0.1, -0.004])

pz = ROOT.RooPolynomial("pz", "pz", z)

bkg = ROOT.RooProdPdf("bkg", "bkg", [px, py, pz])

# Create composite pdf sig+bkg

fsig = ROOT.RooRealVar("fsig", "signal fraction", 0.1, 0.0, 1.0)

model = ROOT.RooAddPdf("model", "model", [sig, bkg], [fsig])

data = model.generate({x, y, z}, 20000)

# Project pdf and data on x

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

# Make plain projection of data and pdf on x observable

frame = x.frame(Title="Projection of 3D data and pdf on X", Bins=40)

data.plotOn(frame)

model.plotOn(frame)

# Project pdf and data on x in signal range

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

# Define signal region in y and z observables

y.setRange("sigRegion", -1, 1)

z.setRange("sigRegion", -1, 1)

# Make plot frame

frame2 = x.frame(Title="Same projection on X in signal range of (Y,Z)", Bins=40)

# Plot subset of data in which all observables are inside "sigRegion"

# For observables that do not have an explicit "sigRegion" range defined (e.g. observable)

# an implicit definition is used that is identical to the full range (i.e.

# [-5,5] for x)

data.plotOn(frame2, CutRange="sigRegion")

# Project model on x, projected observables (y,z) only in "sigRegion"

model.plotOn(frame2, ProjectionRange="sigRegion")

c = ROOT.TCanvas("rf311_rangeplot", "rf310_rangeplot", 800, 400)

c.Divide(2)

c.cd(1)

ROOT.gPad.SetLeftMargin(0.15)

frame.GetYaxis().SetTitleOffset(1.4)

frame.Draw()

c.cd(2)

ROOT.gPad.SetLeftMargin(0.15)

frame2.GetYaxis().SetTitleOffset(1.4)

frame2.Draw()

c.SaveAs("rf311_rangeplot.png")