//-------------------------------------------------------------------
//-------------------------------------------------------------------
//-------------------------------------------------------------------
//-------------------------------------------------------------------
//-------------------------------------------------------------------
Jul 12, 2009
//How to root a file in dCache on the fly:
//root [7] TFile *hfile = new TDCacheFile ("dcap://cmsgridftp.fnal.gov:24125/pnfs/fnal.gov/usr/cms/WAX/11/store/mc/Summer08/MinBias/GEN-SIM-RAW/STARTUP_V5_STARTUP_V5_v1/0007/FEE661F6-606E-DD11-887D-001A9243D528.root","READ",0);


//-------------------------------------------------------------------
April 22, 2009

//  How to Read Objects from a File.  How to loop over objects (histograms)
//on a file

 TIter nextkey(f.GetListOfKeys());
   TKey *key;
   while (key = (TKey*)nextkey()) {
      Event *event = (Event*)key->ReadObj();
      event->Process();
   {



//-------------------------------------------------------------------
April 30, 2009

//How to load some framework to do some on the fly physics analysis

 TFile* _file0 = new TFile("HLTFromPureRaw.root","READ");
    gSystem->Load("/uscmst1/prod/sw/cms/slc4_ia32_gcc345/cms/cmssw/CMSSW_2_2_6_HLT/lib/slc4_ia32_gcc345/libFWCoreFWLite.so");
    AutoLibraryLoader::enable();
    TTree* mytree = (TTree*) _file0->Get("Events");
    int nevt = mytree->GetEntries();
    vector<edm::EventAuxiliary> evt;
    TBranch* cand = mytree->GetBranch("EventAuxiliary");
    vector<edm::EventAuxiliary> evt;  
    cand->SetAddress(&evt);   
    int myevt= -1;
    for (int j = 0;j<nevt;++j){
        cand->GetEntry(j); 
        myevt = evt[0].event();
        cout<<j<<"\t"<<myevt<<endl;
    }


//-------------------------------------------------------------------
// January 19, 2009

// How to run a root macro with arguments:

// $> root -l 'eraseme.C("hola")'
//                      |
//                      |__ watch that there is no spaces here.

// -------------------------------------------------------------------

// May 26, 2008

// To install CERN's ROOT in Ubuntu 8.04 (Heron) I went to:
// http://mirror.phy.bnl.gov/debian-root/ubuntu/
// and followed the instructions there.
// It was successfully installed despite the error in the signature
// verification.


// -------------------------------------------------------------------
// July 20, 2006

// Function to calculate Binomial Errors

Float_t GetBinomialErr(Float_t Passed,Float_t Failed)
{

  if ((Passed+Failed)>0){
    Float_t Total = Passed+Failed;
    Float_t Eff = Passed/Total;
    Float_t DeltaPassed = sqrt(Passed);
    Float_t DeltaFailed = sqrt(Failed);
    Float_t ErrPass = (((1-Eff)*(1-Eff))/(Total*Total))*DeltaPassed*DeltaPassed;
    Float_t ErrFail = ((Eff*Eff)/(Total*Total))*DeltaFailed*DeltaFailed;
    Float_t Err = sqrt(ErrPass+ErrFail);
    return Err;
  }
  else return 0;
}



// -------------------------------------------------------------------
July 13, 2005

// How to dump the contents of a TTree to an ascii file

// ttree->SetScanFiel(0);
// tree->Scan("field1:field2","cond1"); > log.txt  //spaces are important


// -------------------------------------------------------------------
July 13, 2005

// How to run root in batch mode

// make a shell script which you will submit to the batch system and 
//   put in this script the following line:

// root -b -q run.cc