ROOT   Reference Guide
ratioplot2.py File Reference

ratioplot2

## Detailed Description

Example of a fit residual plot.

Creates a histogram filled with random numbers from a gaussian distribution and fits it with a standard gaussian function. The result is passed to the TRatioPlot constructor. Additionally, after calling TRatioPlot::Draw the upper and lower y axis titles are modified. Confidence interval bands are automatically drawn on the bottom (but can be disabled by draw option nobands. Inspired by the tutorial of Paul Gessinger.

import ROOT
ROOT.gStyle.SetOptStat(0)
c1 = ROOT.TCanvas("c1", "fit residual simple")
h1 = ROOT.TH1D("h1", "h1", 50, -5, 5)
h1.FillRandom("gaus", 2000)
h1.Fit("gaus")
h1.GetXaxis().SetTitle("x")
rp1 = ROOT.TRatioPlot(h1)
rp1.Draw()
rp1.GetLowerRefYaxis().SetTitle("ratio")
rp1.GetUpperRefYaxis().SetTitle("entries")
c1.Update()

Definition in file ratioplot2.py.