Ratio plots

I have to plot the ratio pf plots I obtained from RIVET. Plots from RIVET are in TGraphAsymmError.
It’s possible to plot ratio of two histograms but I don’t how to deal with TGraphs.
I have Madgraph & Sherpa results from RIVET in the form of TGraphAsymmError & have data in the form of histogram. I want to draw ratio plots of TGraphAsymmErrors with histogram. For e.g:Data/Madgraph & Data/Sherpa. I’m trying to do so but its it does not work for me. I have attached the code with this thread. Please help.

ratio.C (3.07 KB)

Sorry for the late answer.

You macro gives:

root [0] 
Processing ratio.C...
Error in <TFile::TFile>: file madgraph_zeejets.root does not exist
Error in <TFile::TFile>: file sherpa_zeejets.root does not exist
Error in <TFile::TFile>: file jet2eta.root does not exist
Error: illegal pointer to class object c3 0x0 76  ratio.C:42:
*** Interpreter error recovered ***