void runDigiFOPISimple(TString filename,
		       Int_t field, 
		       TString gas,
		       Int_t gain,
		       TString distfile="", 
		       Int_t nEvents=0) 
{
  // ========================================================================
  // Verbosity level (0=quiet, 1=event level, 2=track level, 3=debug)
  Int_t iVerbose = 0;
  
  // Number of events to process
  //Int_t nEvents = 0;
  
  TString mcMode = "TGeant3";
  // ----  Load libraries   -------------------------------------------------
  TString sysFile = gSystem->Getenv("VMCWORKDIR");
  
  TString inFile = filename;
  TString outFile = filename;
  outFile.ReplaceAll("mc.root", "raw.root");
  //if (distfile!="")
  //    outFile.ReplaceAll("raw.root","disto.raw.root");
  TString parFile = filename;
  parFile.ReplaceAll("mc.root", "param.root");
  
  
  // -----   Timer   --------------------------------------------------------
  TStopwatch timer;
  timer.Start();
  // ------------------------------------------------------------------------
  
  // -----   Digitization run   -------------------------------------------
  FairRunAna *fRun= new FairRunAna();
  fRun->SetInputFile(inFile);
  fRun->SetOutputFile(outFile);
  
  // ------------------------------------------------------------------------
  
  // -----  Parameter database   --------------------------------------------
  TString allDigiFile = sysFile;
  allDigiFile+= Form("/tpc/FOPI/par/tpc.%i%s%iMC.par",field,gas.Data(),gain);
  
  FairRuntimeDb* rtdb = fRun->GetRuntimeDb();
  FairParRootFileIo* parInput1 = new FairParRootFileIo();
  parInput1->open(parFile.Data());
  
  FairParAsciiFileIo* parIo1 = new FairParAsciiFileIo();
  parIo1->open(allDigiFile.Data(),"in");

  rtdb->setFirstInput(parInput1);
  rtdb->setSecondInput(parIo1);
  // ------------------------------------------------------------------------

  // -----   TPC digi producers   ---------------------------------
  TpcEventCounter* evCount =  new TpcEventCounter();
  //  evCount->SetnEvts(nEvents);
  //evCount->SetStep(1);
  fRun->AddTask(evCount); 

  //TpcClusterizerTask* tpcClusterizer = new TpcClusterizerTask();
  //if(mcMode=="TGeant3") tpcClusterizer->SetMereChargeConversion();
  //tpcClusterizer->SetPersistence();
  //fRun->AddTask(tpcClusterizer);
  
  TpcSimpleEvtGen* tpcSimpleEvt = new TpcSimpleEvtGen();
  tpcSimpleEvt->setMode("alongZ");
  tpcSimpleEvt->setPrimGen();
  fRun->AddTask(tpcSimpleEvt);
  
  TpcDriftTask* tpcDrifter = new TpcDriftTask();
  tpcDrifter->SetPersistence();
  if (distfile!="")
    {
      std::cout<<"using distortion file: "<<distfile<<std::endl;
      tpcDrifter->SetDistort(true);
      tpcDrifter->SetDeviationFile(distfile.Data());
    }
  else
    tpcDrifter->SetDistort(false);

  fRun->AddTask(tpcDrifter);
  
  TpcGemTask* tpcGem = new TpcGemTask();
  tpcGem->SetPersistence();
  fRun->AddTask(tpcGem);

  TpcPadResponseTask* tpcPadResponse = new TpcPadResponseTask();
  tpcPadResponse->SetPersistence();
  fRun->AddTask(tpcPadResponse);


  Double_t cal=2.125+0.05+0.05+0.05+0.05;//3.677-0.35-0.32-0.31-0.5;//0.;//3.63433;//2.58544-0.590136;//2.78;
  TpcElectronicsTask* tpcElec = new TpcElectronicsTask();
  tpcElec->SetPersistence();
  tpcElec->SetPSATimeCalib(cal);
  tpcElec->SetSamplePersistence();
  tpcElec->SetShaper("T2K");
  fRun->AddTask(tpcElec);

  TpcElectronicsTask* tpcElec2 = new TpcElectronicsTask();
  //tpcElec2->SetPersistence();
  tpcElec2->SetPSATimeCalib(cal);
  tpcElec2->SetPSA(1);
  tpcElec2->SetSampleBranchName("TpcSample2");
  tpcElec2->SetDigiBranchName("TpcDigi2");
  //tpcElec2->SetSamplePersistence();
  tpcElec2->SetShaper("T2K");
  //fRun->AddTask(tpcElec2);

  // -----   Intialise and run   --------------------------------------------
  fRun->Init();
  fRun->Run(0,nEvents);
  
  rtdb->saveOutput();
  rtdb->print();
  //  tpcDrifter->WriteHistograms();
  // ------------------------------------------------------------------------

  // -----   Finish   -------------------------------------------------------

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