void trackerDigi(){

  // Input files
   TString inFile      = "r3bsim.root";
   TString parFile     = "r3bpar.root";
   TString outFile     = "tra_digi.root";


  // -----   Timer   --------------------------------------------------------
  TStopwatch timer;
  timer.Start();
  // ------------------------------------------------------------------------

  // -----   Digitization run   -------------------------------------------
  FairRunAna *fRun= new FairRunAna();
  fRun->SetInputFile(inFile);
  fRun->SetOutputFile(outFile);

  // Verbosity Mode level
  // (0=quiet, 1=event level, 2=track level, 3=debug)
  Int_t iVerbose = 1;
  //Connect the Digitization  Task

  R3BDchDigitizer* land  = new R3BDchDigitizer();
  fRun->AddTask(land);

  // Runtime DataBase info
  FairRuntimeDb* rtdb = fRun->GetRuntimeDb();
  FairParRootFileIo*  parIo1 = new FairParRootFileIo();
  parIo1->open(parFile.Data());
  rtdb->setFirstInput(parIo1);
  rtdb->setOutput(parIo1);
  rtdb->saveOutput();

  // Load the Root Geometry
  //fRun->LoadGeometry();
  
  // Number of events to process
  Int_t nEvents = 3;
  
  // -----   Intialise and run   --------------------------------------------
  fRun->Init();
  fRun->Run(0, nEvents);

  // -----   Finish   -------------------------------------------------------
  timer.Stop();
  Double_t rtime = timer.RealTime();
  Double_t ctime = timer.CpuTime();
  cout << endl << endl;
  cout << "Macro finished succesfully." << endl;
  cout << "Output file writen:  "    << outFile << endl;
  cout << "Parameter file writen " << parFile << endl;
  cout << "Real time " << rtime << " s, CPU time " << ctime << " s" << endl;
  cout << endl;
  // ------------------------------------------------------------------------


}