Problem in converting TSpectrum Background Class functions to pyROOT

Newbie
1

Hello everyone!
I am trying to implement the background function in TSpectrum class by following the tutorials given in the website.
The C++ (ROOT) Code provided in the tutorial is given below:

void Background_width() {

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 *back = (TH1F*) f->Get("back1");

TH1F *d1 = new TH1F("d1","",nbins,xmin,xmax);

TH1F *d2 = new TH1F("d2","",nbins,xmin,xmax);

TH1F *d3 = new TH1F("d3","",nbins,xmin,xmax);

back->GetXaxis()->SetRange(1,nbins);

back->SetTitle("Influence of clipping window width on the estimated background");

back->Draw("L");

TSpectrum *s = new TSpectrum();

for (i = 0; i < nbins; i++) source[i]=back->GetBinContent(i + 1);

s->Background(source,nbins,4,TSpectrum::kBackDecreasingWindow,

TSpectrum::kBackOrder2,kFALSE,

TSpectrum::kBackSmoothing3,kFALSE);

for (i = 0; i < nbins; i++) d1->SetBinContent(i + 1,source[i]);

d1->SetLineColor(kRed);

d1->Draw("SAME L");

for (i = 0; i < nbins; i++) source[i]=back->GetBinContent(i + 1);

s->Background(source,nbins,6,TSpectrum::kBackDecreasingWindow,

TSpectrum::kBackOrder2,kFALSE,

TSpectrum::kBackSmoothing3,kFALSE);

for (i = 0; i < nbins; i++) d2->SetBinContent(i + 1,source[i]);

d2->SetLineColor(kOrange);

d2->Draw("SAME L");

for (i = 0; i < nbins; i++) source[i]=back->GetBinContent(i + 1);

s->Background(source,nbins,8,TSpectrum::kBackDecreasingWindow,

TSpectrum::kBackOrder2,kFALSE,

TSpectrum::kBackSmoothing3,kFALSE);

for (i = 0; i < nbins; i++) d3->SetBinContent(i + 1,source[i]);

d3->SetLineColor(kGreen);

d3->Draw("SAME L");

}

In pyROOT, the code should look like this:

import ROOT

def Background_width():
  """
  Illustrates the influence of the clipping window width on the estimated background.
  """

  nbins = 1024
  xmin = 0
  xmax = nbins

  # Get the tutorial directory
  dir = ROOT.gROOT.GetTutorialDir()
  file_path = dir + "/spectrum/TSpectrum.root"

  # Open the ROOT file
  f = ROOT.TFile.Open(file_path)

  # Get the background histogram
  back = f.Get("back1")

  # Create histograms for different window widths
  d1 = ROOT.TH1F("d1", "", nbins, xmin, xmax)
  d2 = ROOT.TH1F("d2", "", nbins, xmin, xmax)
  d3 = ROOT.TH1F("d3", "", nbins, xmin, xmax)

  # Set the clipping window range for the background histogram
  back.GetXaxis().SetRange(1, nbins)
  back.SetTitle("Influence of clipping window width on the estimated background")

  # Draw the background histogram
  back.Draw("L")

  # Create a TSpectrum object
  spectrum = ROOT.TSpectrum()

  # Get the bin contents of the background histogram
  source = [back.GetBinContent(i + 1) for i in range(nbins)]

  # Estimate background with window width 4
  spectrum.Background(source, nbins, 4, ROOT.TSpectrum.kBackDecreasingWindow,
                      ROOT.TSpectrum.kBackOrder2, False, ROOT.TSpectrum.kBackSmoothing3, False)

  # Fill the first histogram
  for i in range(nbins):
    d1.SetBinContent(i + 1, source[i])

  d1.SetLineColor(ROOT.kRed)
  d1.Draw("SAME L")

  # Estimate background with window width 6
  spectrum.Background(source, nbins, 6, ROOT.TSpectrum.kBackDecreasingWindow,
                      ROOT.TSpectrum.kBackOrder2, False, ROOT.TSpectrum.kBackSmoothing3, False)

  # Fill the second histogram
  for i in range(nbins):
    d2.SetBinContent(i + 1, source[i])

  d2.SetLineColor(ROOT.kOrange)
  d2.Draw("SAME L")

  # Estimate background with window width 8
  spectrum.Background(source, nbins, 8, ROOT.TSpectrum.kBackDecreasingWindow,
                      ROOT.TSpectrum.kBackOrder2, False, ROOT.TSpectrum.kBackSmoothing3, False)

  # Fill the third histogram
  for i in range(nbins):
    d3.SetBinContent(i + 1, source[i])

  d3.SetLineColor(ROOT.kGreen)
  d3.Draw("SAME L")

# Call the function to execute the code
Background_width()

However, I am getting errors due to the following line:

spectrum.Background(source, nbins, 8, ROOT.TSpectrum.kBackDecreasingWindow,
                      ROOT.TSpectrum.kBackOrder2, False, ROOT.TSpectrum.kBackSmoothing3, False)

I think there is a mistake in ‘ROOT.TSpectrum.kBackOrder2’ and similar syntax.
Can you please help me how to rectify this?
Thanks in advance

2

Hi,

Thanks for the post.
Could you please post also the errors you are seeing, as well as the ROOT version you are using? Slimmig down the example to a few lines would also help a speedy feedback.

Cheers,
Danilo