Example creating a simple ratio plot of two histograms using the pois
division option.
Two histograms are set up and filled with random numbers. The constructor of TRatioPlot
takes the to histograms, name and title for the object, drawing options for the histograms (hist
and E
in this case)
and a drawing option for the output graph.
Inspired by the tutorial of Paul Gessinger.
Author: Alberto Ferro
This notebook tutorial was automatically generated with ROOTBOOK-izer from the macro found in the ROOT repository on Tuesday, March 19, 2024 at 07:11 PM.
import ROOT
ROOT.gStyle.SetOptStat(0)
c1 = ROOT.TCanvas("c1", "A ratio example")
h1 = ROOT.TH1D("h1", "h1", 50, 0, 10)
h2 = ROOT.TH1D("h2", "h2", 50, 0, 10)
f1 = ROOT.TF1("f1", "exp(- x/[0] )")
f1.SetParameter(0,3)
h1.FillRandom("f1",1900)
h2.FillRandom("f1", 2000)
h1.Sumw2()
h2.Scale(1.9/2.)
h1.GetXaxis().SetTitle("x")
h1.GetYaxis().SetTitle("y")
rp = ROOT.TRatioPlot(h1,h2)
c1.SetTicks(0,1)
rp.GetLowYaxis().SetNdivisions(505)
c1.Update()
c1.Draw()
rp.Draw()
Draw all canvases
from ROOT import gROOT
gROOT.GetListOfCanvases().Draw()