Rf 3 0 2_Utilfuncs

Multidimensional models: utility functions classes available for use in tailoring of composite (multidimensional) pdfs

Author: Clemens Lange, Wouter Verkerke (C++ version)
This notebook tutorial was automatically generated with ROOTBOOK-izer from the macro found in the ROOT repository on Monday, January 17, 2022 at 09:57 AM.

In [ ]:
import ROOT

Create observables, parameters

Create observables

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

Create parameters

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a0 = ROOT.RooRealVar("a0", "a0", -1.5, -5, 5)
a1 = ROOT.RooRealVar("a1", "a1", -0.5, -1, 1)
sigma = ROOT.RooRealVar("sigma", "width of gaussian", 0.5)

Using RooFormulaVar to tailor pdf

Create interpreted function f(y) = a0 - a1sqrt(10abs(y))

In [ ]:
fy_1 = ROOT.RooFormulaVar("fy_1", "a0-a1*sqrt(10*abs(y))", [y, a0, a1])

Create gauss(x,f(y),s)

In [ ]:
model_1 = ROOT.RooGaussian("model_1", "Gaussian with shifting mean", x, fy_1, sigma)

Using RooPolyVar to tailor pdf

Create polynomial function f(y) = a0 + a1*y

In [ ]:
fy_2 = ROOT.RooPolyVar("fy_2", "fy_2", y, [a0, a1])

Create gauss(x,f(y),s)

In [ ]:
model_2 = ROOT.RooGaussian("model_2", "Gaussian with shifting mean", x, fy_2, sigma)

Using RooAddition to tailor pdf

Create sum function f(y) = a0 + y

In [ ]:
fy_3 = ROOT.RooAddition("fy_3", "a0+y", [a0, y])

Create gauss(x,f(y),s)

In [ ]:
model_3 = ROOT.RooGaussian("model_3", "Gaussian with shifting mean", x, fy_3, sigma)

Using RooProduct to tailor pdf

Create product function f(y) = a1*y

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fy_4 = ROOT.RooProduct("fy_4", "a1*y", [a1, y])

Create gauss(x,f(y),s)

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model_4 = ROOT.RooGaussian("model_4", "Gaussian with shifting mean", x, fy_4, sigma)

Plot all pdfs

Make two-dimensional plots in x vs y

In [ ]:
hh_model_1 = model_1.createHistogram("hh_model_1", x, Binning=50, YVar=dict(var=y, Binning=50))
hh_model_2 = model_2.createHistogram("hh_model_2", x, Binning=50, YVar=dict(var=y, Binning=50))
hh_model_3 = model_3.createHistogram("hh_model_3", x, Binning=50, YVar=dict(var=y, Binning=50))
hh_model_4 = model_4.createHistogram("hh_model_4", x, Binning=50, YVar=dict(var=y, Binning=50))
hh_model_1.SetLineColor(ROOT.kBlue)
hh_model_2.SetLineColor(ROOT.kBlue)
hh_model_3.SetLineColor(ROOT.kBlue)
hh_model_4.SetLineColor(ROOT.kBlue)

Make canvas and draw ROOT.RooPlots

In [ ]:
c = ROOT.TCanvas("rf302_utilfuncs", "rf302_utilfuncs", 800, 800)
c.Divide(2, 2)
c.cd(1)
ROOT.gPad.SetLeftMargin(0.20)
hh_model_1.GetZaxis().SetTitleOffset(2.5)
hh_model_1.Draw("surf")
c.cd(2)
ROOT.gPad.SetLeftMargin(0.20)
hh_model_2.GetZaxis().SetTitleOffset(2.5)
hh_model_2.Draw("surf")
c.cd(3)
ROOT.gPad.SetLeftMargin(0.20)
hh_model_3.GetZaxis().SetTitleOffset(2.5)
hh_model_3.Draw("surf")
c.cd(4)
ROOT.gPad.SetLeftMargin(0.20)
hh_model_4.GetZaxis().SetTitleOffset(2.5)
hh_model_4.Draw("surf")

c.SaveAs("rf302_utilfuncs.png")

Draw all canvases

In [ ]:
from ROOT import gROOT 
gROOT.GetListOfCanvases().Draw()