void trim() {
  gROOT->SetStyle("Plain");

  TCanvas *c1;
  c1=new TCanvas("c1","Canvas",600,600);

  const unsigned ne(16);
  double e[ne]={  3.9, 10.5, 16.6, 23.3, 33.8, 41.4, 47.7, 55.8,
		 63.9, 72.2, 80.2, 90.0,105.3,117.7,129.7,145.2};

  TF1 *func=new TF1("func","sqrt([0]*[0]+[1]*[1]*x*x)",0.0,2.0);
  func->SetParameters(0.01,0.2);

  TGraph *tg;
  tg=new TGraph(ne);
  tg->SetTitle(";Trim value;Pedestal (DTU)");

  for(int j(0);j<(int)ne;j++) {
    tg->SetPoint(j,j,e[j]);
  }
    
  tg->SetMarkerStyle(20);
  tg->SetMarkerSize(1.5);
  tg->SetMarkerColor(2);
  tg->SetLineColor(2);
    
  tg->Fit("pol2");
  tg->GetFunction("pol2")->SetLineColor(2);
    
  //tg->GetYaxis()->SetRangeUser(0,15);
  tg->GetXaxis()->SetRangeUser(0,15);
  tg->GetYaxis()->SetTitleOffset(1.3);
    
  tg->Draw("AP");
    
  c1->Update();
  c1->Print("../trim.png");
}