Error in <TTree::SetBranchAddress>: The pointer type given "TH1F" does not correspond to the type needed "Float_t" (5) by the branch

ROOT
, ,
1

Hello,

I’m new to ROOT, my goal is to read a histogram data from my root file. This is my code:

#include <TFile.h>
#include <TTree.h>
#include <TH1F.h>

void histogram() {

  TFile *file = TFile::Open("events.root");
  TTree *tree = (TTree*)file->Get("Delphes");
  
  TH1F *hist = new TH1F();
  tree->SetBranchAddress("GenJet.PT", &hist);
  
   for (Long64_t i = 0; i < tree->GetEntries(); i++) {
    tree->GetEntry(i);
    hist->Draw();
  }
  
  file->Close();
}

When I run my code, an empty histogram is plotted and I get the error:

Error in < TTree::SetBranchAddress>: The pointer type given “TH1F” does not correspond to the type needed “Float_t” (5) by the branch: GenJet.PT

And If I try to adjust the part below as such, I don’t get any error messages but the plotted canvas is empty:

  TH1F *hist = new TH1F("GenJet_PT", "GenJet PT", 100, 0, 1000);

  Float_t pt;
  tree->SetBranchAddress("GenJet.PT", &pt);

  for (Long64_t i = 0; i < tree->GetEntries(); i++) {
    tree->GetEntry(i);
    hist->Fill(pt);
  }

  hist->Draw();

I’d be happy if someone could help.
Thank you.

ROOT Version: 6.26.10
Platform: Ubuntu 20.04.5

2
3

Thank you for your response,

I checked them but there are too many information for me to understand really. Is there a way that you can be more specific ?

4

root -b -q events.root -e 'Delphes->MakeClass();'

5

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