hist010_TH1_two_scales.py File Reference

Detailed Description

Example of macro illustrating how to superimpose two histograms with different scales in the "same" pad.

Inspired by work of Rene Brun.

 
import ROOT
import numpy as np
 
c1 = ROOT.TCanvas("c1","hists with different scales",600,400)
 
ROOT.gStyle.SetOptStat(False)
 
h1 = ROOT.TH1F("h1","my histogram",100,-3,3)
 
h1.Fill(np.array([ROOT.gRandom.Gaus(0, 1) for _ in range(10000)]))
 
h1.Draw()
c1.Update()
 
hint1 = ROOT.TH1F("hint1","h1 bins integral",100,-3,3)
 
sum = 0
for i in range(1,101) :
   sum += h1.GetBinContent(i)
   hint1.SetBinContent(i,sum)
 
rightmax = 1.1*hint1.GetMaximum()
scale = ROOT.gPad.GetUymax()/rightmax
hint1.SetLineColor("kRed")
hint1.Scale(scale)
hint1.Draw("same")
 
axis = ROOT.TGaxis(ROOT.gPad.GetUxmax(),ROOT.gPad.GetUymin(),
      ROOT.gPad.GetUxmax(), ROOT.gPad.GetUymax(),0,rightmax,510,"+L")
axis.SetLineColor("kRed")
axis.SetLabelColor("kRed")
axis.Draw()

Author

Alberto Ferro

Definition in file hist010_TH1_two_scales.py.