refMultReader/refMultReader.C

#define refMultReader_cxx
#include "refMultReader.h"
#include <TH2.h>
#include <TStyle.h>
#include <TFile.h>
#include <TCanvas.h>

#include <iostream>

void refMultReader::Loop(const char* outfile)
{
//   In a ROOT session, you can do:
//      root> .L refMultReader.C
//      root> refMultReader t
//      root> t.GetEntry(12); // Fill t data members with entry number 12
//      root> t.Show();       // Show values of entry 12
//      root> t.Show(16);     // Read and show values of entry 16
//      root> t.Loop();       // Loop on all entries
//

//     This is the loop skeleton where:
//    jentry is the global entry number in the chain
//    ientry is the entry number in the current Tree
//  Note that the argument to GetEntry must be:
//    jentry for TChain::GetEntry
//    ientry for TTree::GetEntry and TBranch::GetEntry
//
//       To read only selected branches, Insert statements like:
// METHOD1:
//    fChain->SetBranchStatus("*",0);  // disable all branches
//    fChain->SetBranchStatus("branchname",1);  // activate branchname
// METHOD2: replace line
//    fChain->GetEntry(jentry);       //read all branches
//by  b_branchname->GetEntry(ientry); //read only this branch
   if (fChain == 0) return;

   TH1F *hMult = new TH1F("hRefMult","refMult (|#eta|<0.5, p_{T}>0.15 GeV/c)",2500,0.,2500.);

   // Long64_t nentries = fChain->GetEntriesFast();
   Long64_t nentries = 500e3;

   Long64_t nbytes = 0, nb = 0;
   Int_t refMult;
   for (Long64_t jentry=0; jentry<nentries;jentry++) {
      Long64_t ientry = LoadTree(jentry);
      if (ientry < 0) break;
      nb = fChain->GetEntry(jentry);   nbytes += nb;
      // if (Cut(ientry) < 0) continue;
      if (jentry%1000==0) std::cout << "Event [" << jentry << "/"
				<< nentries << "]" << std::endl;
      refMult = 0;
      for (int iTr=0; iTr<n_tracks_mpd; iTr++)
      {
        if (TMath::Abs(signed_pt_mpd[iTr]) < 0.15) continue;
        if (TMath::Abs(eta_mpd[iTr]) > 0.5) continue;
        if (n_hits_mpd[iTr] < 32) continue;
        refMult++;
      }
      hMult->Fill(refMult);
   }
   TFile *fo = new TFile(outfile,"recreate");
   fo->cd();
   hMult->Write();
   fo->Close();
}