void Smoothing()
{
   Int_t i;
   const Int_t nbins = 1024;
   Double_t xmin = 0;
   Double_t xmax = nbins;
   Double_t source[nbins];
   gROOT->ForceStyle();

   TString dir = gROOT->GetTutorialDir();
   TString file = dir + "/legacy/spectrum/TSpectrum.root";
   TFile *f = new TFile(file.Data());
   TH1F *h = (TH1F *)f->Get("back1");
   h->SetTitle("Smoothed spectrum for m=3");

   for (i = 0; i < nbins; i++)
      source[i] = h->GetBinContent(i + 1);
   h->SetAxisRange(1, 1024);
   h->Draw("L");

   TSpectrum *s = new TSpectrum();

   TH1F *smooth = new TH1F("smooth", "smooth", nbins, 0., nbins);
   smooth->SetLineColor(kRed);

   s->SmoothMarkov(source, 1024, 3); // 3, 7, 10
   for (i = 0; i < nbins; i++)
      smooth->SetBinContent(i + 1, source[i]);
   smooth->Draw("L SAME");
}