{
  TFile f("test.root");
  TH1F* ratio = (TH1F*)f.Get("ratio");

  TCanvas *c = new TCanvas();

  //firstly, fit the histogram
  cout << "ORIGINAL FIT PARAMETERS:" << endl;
  ratio->Fit("pol9","","",-2.7, -1.5);

  //secondly, recreate fitted function (pol9, same parameters - check the printout) 
  // parameters set simply by copy&paste the screen values from the old fit
  TF1* newfit = new TF1("newfit","pol9(0)",-2.7, -1.5);
  newfit->SetParameters(-1.018780e+04,-3.491464e+04,-4.678893e+04,-2.682289e+04,9.744418e+02,1.096072e+04,7.051491e+03,2.204937e+03,3.564453e+02,2.388579e+01);

  cout << "PARAMETERS OF RECREATED FUNCTION:" << endl;
  newfit->Print();

  newfit->SetLineColor(kRed);
  newfit->Draw("same");

  //result - newfit is a different function
  //possible reason would be that printout parameters of the original fitted function are ROUNDED ( = not precise enough to recreate new function!)
  //creating "newfitDouble" directly by reading original parameters as DOUBLE works! (blue function is equal to the original one (black))

  TF1* newfitDouble = new TF1("newfitDouble","pol9(0)",-2.7, -1.5);

  cout << "PARAMETERS DIFFERENCE:" << endl;
  for (int i=0; i<= 9; i++)
    {
      double oldpar = ratio->GetFunction("pol9")->GetParameter(i);
      double newpar = newfit->GetParameter(i);
      cout << "difference in parameter " << i << " : " << oldpar-newpar << endl;
      newfitDouble->SetParameter(i, oldpar);
    }

  newfitDouble->SetLineColor(kBlue);
  newfitDouble->SetLineStyle(2);
  newfitDouble->Draw("same");
}