void macro()
{

  TString varXname = "variableX";
  TString varYname = "variableY";
  int nScanSteps = 30;
  int nScanStepsY = 30;

  TH2D* h1 = new TH2D("Dummy","",nScanSteps,1,2,nScanStepsY,1,2);
  TF2 *xyg = new TF2("xyg","xygaus",1,2,1,2); 
  xyg->SetParameters(1,1.5,0.25,1.5,0.25);
  h1->FillRandom("xyg");

  gStyle->SetOptStat(0);
  gStyle->SetPalette(kBird);
  TCanvas *c1 = new TCanvas("c1","",200,10,800,600);

  h1->GetXaxis()->SetTitle(varXname);
  h1->GetYaxis()->SetTitle(varYname);

  h1->GetZaxis()->SetTitle("-#DeltalogL");
  h1->GetXaxis()->CenterTitle();
  h1->GetYaxis()->CenterTitle();
  h1->GetZaxis()->CenterTitle();

  Int_t binxx, binyy, bin; 
  Int_t xbin = h1->GetXaxis()->GetNbins();
  Int_t ybin = h1->GetYaxis()->GetNbins();
  double min = h1->GetMinimum();
  std::cout << "hist minimum value: " << min << std::endl;
  for(int i=1; i<xbin+1; i++) {
    for(int j=1; j<ybin+1; j++) {
      double_t binContent = h1->GetBinContent(i, j);
      h1->SetBinContent(i, j, binContent - min);
      double_t newbinContent = h1->GetBinContent(i, j);
    }
  }  
  
  double zMaximum = h1->GetMaximum();
  h1->GetZaxis()->SetRangeUser(-1e-100, zMaximum);
  h1->Draw("col z");

  TMarker *marker = new TMarker(500,300,29);
  // marker->SetMarkerColor(2);
  // marker->SetMarkerSize(20);
  marker->Draw("");

  TString outputFilePath = "myTestDirectory/";
  c1->SaveAs(outputFilePath + "NLLscan_"+varXname+"_"+varYname+"_histo_2D.png");
  c1->SaveAs(outputFilePath + "NLLscan_"+varXname+"_"+varYname+"_histo_2D.pdf");

  TFile *output = new TFile(outputFilePath + "/NLLscan_"+varXname+"_"+varYname+"_histo_2D.root", "RECREATE");
  output->cd();
  h1->Write();
  output->Close();
  delete output;
}