[ROOT] Dividing histograms from a TChain

From: Emily Nurse (emily@pc56.hep.man.ac.uk)
Date: Mon Jan 14 2002 - 16:16:12 MET


Hello,
Sorry if this is a simple question.......
I am trying to divide two histograms, each one comes from a TChain made up
of .root files. I realse the histograms have to be renamed before they can
be divided but the suggested way of doing this is using:

TFile *f = new TFile("myfile.root");

f->ls();
   TH2D   h810;1  Hist title
   TH2D   h811;1  Hist title

h810->Draw();  // this works
h811->Draw();  // this works

TH2D *num = (TH2D*)f->Get("h810");
TH2D *den = (TH2D*)f->Get("h811");

num->Divide(den);  //  this works!

how-ever I have more than one file so what would I need to put in place of
f in this example?
Thanks
Emily.



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