root/html/Smoothing_8C.html

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+"/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");
}