void pisa_to_ntuple()
{
//////////////////////////////////////////////////////////
//   This file has been automatically generated 
//     (Fri Apr  8 17:55:21 2005 by ROOT version4.01/02)
//   from TTree AncSvx/SVX Ancestors
//   found on file: ancsvx_057.root
//   do:
//  root -l ancsvx_057.root
//  .ls shows an Ntuple: AncSvx;1
//  AncSvx->MakeCode("macroname.C");
//
//////////////////////////////////////////////////////////


//Reset ROOT and connect tree file
   gROOT->Reset();

// This is for a single file: 
//   TFile *f = (TFile*)gROOT->GetListOfFiles()->FindObject("ancsvx_softlink.root");
//   if (!f) {
//     cout<<" using ancsvx_softlink.root "<<endl;
//      f = new TFile("ancsvx_softlink.root");
//   }
//   TCain is a TTree     TTree *AncSvx = (TTree*)gDirectory->Get("AncSvx");

// This is for a chain of files: 
TChain chain("AncSvx");

//cout <<"adding ancsvx_40.root"<<endl;
//chain.Add("batch_40/ancsvx_40.root");     // 40 not OK

cout <<"adding ancsvx_41.root"<<endl;
chain.Add("batch_41/ancsvx_41.root");     // 41 OK

cout <<"adding ancsvx_42.root"<<endl;
chain.Add("batch_42/ancsvx_42.root");     // 42 OK

cout <<"adding ancsvx_43.root"<<endl;
chain.Add("batch_43/ancsvx_43.root");     // 43 ok

cout <<"adding ancsvx_45.root"<<endl;
chain.Add("batch_45/ancsvx_45.root");     // 45 OK

//Declaration of leaves types
   Float_t  TRACK;
   Float_t  NFILE;
   Float_t  PTOT;
   Float_t  PTHETA;
   Float_t  PPHI;
   Float_t  R_VERTEX;
   Float_t  Z_VERTEX;
   Float_t  THET_VER;
   Float_t  PHI_VER;
   Float_t  ITPARENT;
   Float_t  IDPARENT;
   Float_t  IDPART;
   Float_t  ITORIGIN;
   Float_t  IDORIGIN;
   Float_t  IHIT;
   Float_t  LAYER;
   Float_t  THETA;
   Float_t  PHI;
   Float_t  XGLOBAL;
   Float_t  YGLOBAL;
   Float_t  ZGLOBAL;
   Float_t  PMOMX;
   Float_t  PMOMY;
   Float_t  PMOMZ;
   Float_t  IPC123;
   Float_t  PC1THETA;
   Float_t  PC1PHI;
   Float_t  PC1RDIST;
   Float_t  PC1ZDIST;
   Float_t  PC2THETA;
   Float_t  PC2PHI;
   Float_t  PC2RDIST;
   Float_t  PC2ZDIST;
   Float_t  PC3THETA;
   Float_t  PC3PHI;
   Float_t  PC3RDIST;
   Float_t  PC3ZDIST;
   Float_t  DELE;
   Float_t  XLOCIN;
   Float_t  YLOCIN;
   Float_t  ZLOCIN;
   Float_t  XLOCOUT;
   Float_t  YLOCOUT;
   Float_t  ZLOCOUT;
   Float_t  HITVOL0;
   Float_t  HITVOL1;
   Float_t  HITVOL2;
   Float_t  HITVOL3;
   Float_t  HITVOL4;
   Float_t  HITVOL5;
   Float_t  NHIT;
   Float_t  X0_EVENT;
   Float_t  Y0_EVENT;
   Float_t  Z0_EVENT;
   Float_t  B_IMPACT;
   Float_t  EVENT;

   // Set branch addresses.
   AncSvx->SetBranchAddress("TRACK",&TRACK);
   AncSvx->SetBranchAddress("NFILE",&NFILE);
   AncSvx->SetBranchAddress("PTOT",&PTOT);
   AncSvx->SetBranchAddress("PTHETA",&PTHETA);
   AncSvx->SetBranchAddress("PPHI",&PPHI);
   AncSvx->SetBranchAddress("R_VERTEX",&R_VERTEX);
   AncSvx->SetBranchAddress("Z_VERTEX",&Z_VERTEX);
   AncSvx->SetBranchAddress("THET_VER",&THET_VER);
   AncSvx->SetBranchAddress("PHI_VER",&PHI_VER);
   AncSvx->SetBranchAddress("ITPARENT",&ITPARENT);
   AncSvx->SetBranchAddress("IDPARENT",&IDPARENT);
   AncSvx->SetBranchAddress("IDPART",&IDPART);
   AncSvx->SetBranchAddress("ITORIGIN",&ITORIGIN);
   AncSvx->SetBranchAddress("IDORIGIN",&IDORIGIN);
   AncSvx->SetBranchAddress("IHIT",&IHIT);
   AncSvx->SetBranchAddress("LAYER",&LAYER);
   AncSvx->SetBranchAddress("THETA",&THETA);
   AncSvx->SetBranchAddress("PHI",&PHI);
   AncSvx->SetBranchAddress("XGLOBAL",&XGLOBAL);
   AncSvx->SetBranchAddress("YGLOBAL",&YGLOBAL);
   AncSvx->SetBranchAddress("ZGLOBAL",&ZGLOBAL);
   AncSvx->SetBranchAddress("PMOMX",&PMOMX);
   AncSvx->SetBranchAddress("PMOMY",&PMOMY);
   AncSvx->SetBranchAddress("PMOMZ",&PMOMZ);
   AncSvx->SetBranchAddress("IPC123",&IPC123);
   AncSvx->SetBranchAddress("PC1THETA",&PC1THETA);
   AncSvx->SetBranchAddress("PC1PHI",&PC1PHI);
   AncSvx->SetBranchAddress("PC1RDIST",&PC1RDIST);
   AncSvx->SetBranchAddress("PC1ZDIST",&PC1ZDIST);
   AncSvx->SetBranchAddress("PC2THETA",&PC2THETA);
   AncSvx->SetBranchAddress("PC2PHI",&PC2PHI);
   AncSvx->SetBranchAddress("PC2RDIST",&PC2RDIST);
   AncSvx->SetBranchAddress("PC2ZDIST",&PC2ZDIST);
   AncSvx->SetBranchAddress("PC3THETA",&PC3THETA);
   AncSvx->SetBranchAddress("PC3PHI",&PC3PHI);
   AncSvx->SetBranchAddress("PC3RDIST",&PC3RDIST);
   AncSvx->SetBranchAddress("PC3ZDIST",&PC3ZDIST);
   AncSvx->SetBranchAddress("DELE",&DELE);
   AncSvx->SetBranchAddress("XLOCIN",&XLOCIN);
   AncSvx->SetBranchAddress("YLOCIN",&YLOCIN);
   AncSvx->SetBranchAddress("ZLOCIN",&ZLOCIN);
   AncSvx->SetBranchAddress("XLOCOUT",&XLOCOUT);
   AncSvx->SetBranchAddress("YLOCOUT",&YLOCOUT);
   AncSvx->SetBranchAddress("ZLOCOUT",&ZLOCOUT);
   AncSvx->SetBranchAddress("HITVOL0",&HITVOL0);
   AncSvx->SetBranchAddress("HITVOL1",&HITVOL1);
   AncSvx->SetBranchAddress("HITVOL2",&HITVOL2);
   AncSvx->SetBranchAddress("HITVOL3",&HITVOL3);
   AncSvx->SetBranchAddress("HITVOL4",&HITVOL4);
   AncSvx->SetBranchAddress("HITVOL5",&HITVOL5);
   AncSvx->SetBranchAddress("NHIT",&NHIT);
   AncSvx->SetBranchAddress("X0_EVENT",&X0_EVENT);
   AncSvx->SetBranchAddress("Y0_EVENT",&Y0_EVENT);
   AncSvx->SetBranchAddress("Z0_EVENT",&Z0_EVENT);
   AncSvx->SetBranchAddress("B_IMPACT",&B_IMPACT);
   AncSvx->SetBranchAddress("EVENT",&EVENT);
   
  TNtuple *p2n;
  p2n = new TNtuple("p2n","pisa ntuple","event:track:idpart:ptot:x0ev:y0ev:z0ev:x1:y1:z1:x2:y2:z2:x3:y3:z3:x4:y4:z4:x5:y5:z5:x6:y6:z6:x7:y7:z7:x8:y8:z8:x9:y9:z9:x10:y10:z10:x11:y11:z11:x12:y12:z12");
  TH1F *t1 = new TH1F("t1","layer ", 20, 0.0, 20);

//     This is the loop skeleton
//       To read only selected branches, Insert statements like:
// AncSvx->SetBranchStatus("*",0);  // disable all branches
// TTreePlayer->SetBranchStatus("branchname",1);  // activate branchname

   Long64_t nentries = AncSvx->GetEntries();

  Float_t oldevent =0;
  //Int_t oldevent = -1;
  Int_t mult0    = 0;
  Int_t mult1    = 0;
  Int_t oldtrack = 0;
  Float_t delz   = 0;
  Int_t nbytes   = 0;
  Float_t phi    = 0.0;
  Float_t phi2   = 0.0;
  Float_t r      = 0.0;
  Float_t eta, x2, y2, sign;
  Float_t pi=  TMath::Pi();
  Float_t degtorad = pi/180.;
  Float_t r_global, s_global, the_global, phi_global, del_the, del_phi;
  Float_t z_global, dr_the, dr_phi, resid;
  float arr[43];
  for (int j=0; j<43; j++){arr[j] = 0.0; }

  for (Long64_t i=0; i<nentries;i++) {            // master loop over records
    nbytes += AncSvx->GetEntry(i);                // pull in the record
    //cout<<"1)  event, track, layer, z = "<<EVENT<<" "<<TRACK<<" "<<LAYER<<" "<<ZGLOBAL<<endl;
    if (i==0) { oldevent = EVENT; }
    if (EVENT != oldevent) {                      // new event
      oldevent = EVENT;
      //cout<<"New event seen: "<<EVENT<<endl;
      if (oldevent != 1) {        // do end-of-event stats
        //cout<<"#of records for event "<<EVENT-1<<" was "<<mult0<<endl;
	p2n->Fill(arr);
        for (int j=0; j<43; j++){arr[j] = 0.0; }
      }
      mult0 = 1;                   // reset multiplicity counter
    }
    else {                                        // we're in the same event
      //cout<<"2)  event, track, layer, z = "<<EVENT<<" "<<TRACK<<" "<<LAYER<<" "<<ZGLOBAL<<endl;
      int j=0;
      arr[j++] = EVENT;
      arr[j++] = TRACK;
      arr[j++] = IDPART;
      arr[j++] = PTOT;
      //cout <<"event, layer: "<<EVENT<<" "<<LAYER<<endl;   
      t1->Fill(LAYER);   
      if (LAYER>=1 && LAYER<=12) {
        arr[3+int(LAYER)*3+1] = XGLOBAL;
        arr[3+int(LAYER)*3+2] = YGLOBAL;
        arr[3+int(LAYER)*3+3] = ZGLOBAL;
      }
    }        // same event
  }          // loop over records
  cout<<"End of file seen: "<<EVENT<<endl;
  cout<<"#of records for event "<<EVENT<<" was "<<mult0<<endl;
  //  TFile *tfile = new TFile("p2n.root","recreate","pisa to ntuple");
  //tfile->Write();
  //tfile->Close();

  // -------------------------------------- now analyse p2n -------------------------
  Long64_t nentries = p2n->GetEntries();
  //nentries = 10;
  cout<<"netries in ntuple p2n = "<<nentries<<endl;
 
  Float_t  event,track,idpart,ptot,x0ev,y0ev,z0ev,
           x1,y1,z1,x2,y2,z2,x3,y3,z3,x4,y4,z4,x5,y5,z5,x6,y6,z6,
           x7,y7,z7,x8,y8,z8,x9,y9,z9,x10,y10,z10,x11,y11,z11,x12,y12,z12;
 
  p2n->SetBranchAddress("ptot",&ptot);    p2n->SetBranchAddress("event",&event);
  p2n->SetBranchAddress("track",&track);  p2n->SetBranchAddress("idpart",&idpart);
  p2n->SetBranchAddress("ptot",&ptot);    p2n->SetBranchAddress("x0ev",&x0ev);
  p2n->SetBranchAddress("y0ev",&y0ev);    p2n->SetBranchAddress("z0ev",&z0ev);
  p2n->SetBranchAddress("x1",&x1);  p2n->SetBranchAddress("y1",&y1);
  p2n->SetBranchAddress("z1",&z1);  p2n->SetBranchAddress("x2",&x2);
  p2n->SetBranchAddress("y2",&y2);  p2n->SetBranchAddress("z2",&z2);
  p2n->SetBranchAddress("x3",&x3);  p2n->SetBranchAddress("y3",&y3);
  p2n->SetBranchAddress("z3",&z3);  p2n->SetBranchAddress("x4",&x4);
  p2n->SetBranchAddress("y4",&y4);  p2n->SetBranchAddress("z4",&z4);
  p2n->SetBranchAddress("x5",&x5);  p2n->SetBranchAddress("y5",&y5);
  p2n->SetBranchAddress("z5",&z5);  p2n->SetBranchAddress("x6",&x6);
  p2n->SetBranchAddress("y6",&y6);  p2n->SetBranchAddress("z6",&z6);
  p2n->SetBranchAddress("x7",&x7);  p2n->SetBranchAddress("y7",&y7);
  p2n->SetBranchAddress("z7",&z7);  p2n->SetBranchAddress("x8",&x8);
  p2n->SetBranchAddress("y8",&y8);  p2n->SetBranchAddress("z8",&z8);
  p2n->SetBranchAddress("x9",&x9);  p2n->SetBranchAddress("y9",&y9);
  p2n->SetBranchAddress("z9",&z9);  p2n->SetBranchAddress("x10",&x10);
  p2n->SetBranchAddress("y10",&y10);  p2n->SetBranchAddress("z10",&z10);
  p2n->SetBranchAddress("x11",&x11);  p2n->SetBranchAddress("y11",&y11);
  p2n->SetBranchAddress("z11",&z11);  p2n->SetBranchAddress("x12",&x12);
  p2n->SetBranchAddress("y12",&y12);  p2n->SetBranchAddress("z12",&z12);
 
  for (Long64_t i=0; i<nentries;i++) {            // master loop over records
    nbytes += p2n->GetEntry(i);                // pull in the record
    
  }

}                       // end of macro