void plotCurr(const int iwaferlot=29,
	      const int nbinsX = 100,
	      const int nbinsY = 100,
	      const char *fname="result.root"
	      )
{
  TFile *inFile = TFile::Open(fname);

  const int debug = 0;

  // constants for arrays 
  const int kNChan = 32;
  const int kNQR = 26;
  const int kNVRef = 6;
  const int kNACurr = 5;
  const int kNSync = 8;

  TTree *tree = (TTree*) inFile->Get("tree");

  //Declaration of leaves types
  //Declaration of leaves types
  Char_t          filename[200];
  Char_t          datetime[100];
  Char_t          cQR[kNQR];
  Int_t           iChip;
  Int_t           iSta;
  Float_t         fVRef[kNVRef];
  Float_t         fVCurr[kNACurr];
  Float_t         fACurr[kNACurr];
  Float_t         fGain20mV[32];
  Float_t         fGain30mV[32];
  Float_t         fGainRT20mV[32];
  Float_t         fGainRT30mV[32];
  Float_t         fRT20mV[32];
  Float_t         fRT30mV[32];
  Float_t         fPed20mV[32];
  Float_t         fPed30mV[32];
  Float_t         fRms20mV[32];
  Float_t         fRms30mV[32];
  Float_t         fPedAna20mV[32];
  Float_t         fPedAna30mV[32];
  Float_t         fRmsAna20mV[32];
  Float_t         fRmsAna30mV[32];
  Float_t         fX20mVeven;
  Float_t         fX20mVodd;
  Float_t         fX30mVeven;
  Float_t         fX30mVodd;
  Int_t           iSync[kNSync];
  Int_t           iDFT;
  Int_t           iJtag;
  Int_t           iMem;
  Float_t         fRingOsc;
  Int_t           i2cErr;
  Int_t           iErrCode;
  Int_t           iRCode;
  
  // Set branch addresses.
  tree->SetBranchAddress("filename",filename);
  tree->SetBranchAddress("datetime",datetime);
  tree->SetBranchAddress("cQR",&cQR);
  tree->SetBranchAddress("iChip",&iChip);
  tree->SetBranchAddress("iSta",&iSta);
  tree->SetBranchAddress("fVRef",fVRef);
  tree->SetBranchAddress("fVCurr",fVCurr);
  tree->SetBranchAddress("fACurr",fACurr);
  tree->SetBranchAddress("fGain20mV",fGain20mV);
  tree->SetBranchAddress("fGain30mV",fGain30mV);
  tree->SetBranchAddress("fGainRT20mV",fGainRT20mV);
  tree->SetBranchAddress("fGainRT30mV",fGainRT30mV);
  tree->SetBranchAddress("fRT20mV",fRT20mV);
  tree->SetBranchAddress("fRT30mV",fRT30mV);
  tree->SetBranchAddress("fPed20mV",fPed20mV);
  tree->SetBranchAddress("fPed30mV",fPed30mV);
  tree->SetBranchAddress("fRms20mV",fRms20mV);
  tree->SetBranchAddress("fRms30mV",fRms30mV);
  tree->SetBranchAddress("fPedAna20mV",fPedAna20mV);
  tree->SetBranchAddress("fPedAna30mV",fPedAna30mV);
  tree->SetBranchAddress("fRmsAna20mV",fRmsAna20mV);
  tree->SetBranchAddress("fRmsAna30mV",fRmsAna30mV);
  tree->SetBranchAddress("fX20mVeven",&fX20mVeven);
  tree->SetBranchAddress("fX20mVodd",&fX20mVodd);
  tree->SetBranchAddress("fX30mVeven",&fX30mVeven);
  tree->SetBranchAddress("fX30mVodd",&fX30mVodd);
  tree->SetBranchAddress("iSync",iSync);
  tree->SetBranchAddress("iDFT",&iDFT);
  tree->SetBranchAddress("iJtag",&iJtag);
  tree->SetBranchAddress("iMem",&iMem);
  tree->SetBranchAddress("fRingOsc",&fRingOsc);
  tree->SetBranchAddress("i2cErr",&i2cErr);
  tree->SetBranchAddress("iErrCode",&iErrCode);
  tree->SetBranchAddress("iRCode",&iRCode);
  
  //     This is the loop skeleton
  //       To read only selected branches, Insert statements like:
  // tree->SetBranchStatus("*",0);  // disable all branches
  // TTreePlayer->SetBranchStatus("branchname",1);  // activate branchname
  Long64_t nentries = tree->GetEntries();

  // histos: 
  const int kNHistMax = kNACurr;
  TH1F *h1[kNHistMax];
  TProfile *hp[kNHistMax];
  TH2F *h2[kNHistMax];
  const char *strCurrTitle[] = { "FE1_CURR (mA)", "FE2_CURR (mA)", "AD_CURR (mA)",  "DR_CURR (mA)",  "DG_CURR (mA)" };  
  const char *strCurr[] = { "FE1_CURR", "FE2_CURR", "AD_CURR",  "DR_CURR",  "DG_CURR" };  

  int j = 0;
  char id[100];
  int nbinsXY = nbinsX * nbinsY;
  int nbinsProf = nbinsY; // one per row

  // first, create all histos
  for (j = 0; j<kNHistMax; j++) {

    sprintf(id, "h1%d", j);
    h1[j] = new TH1F(id, strCurrTitle[j], 
		     nbinsXY, -0.5, nbinsXY - 0.5);

    sprintf(id, "hp%d", j);
    hp[j] = new TProfile(id, strCurrTitle[j], 
			 nbinsProf, -0.5, nbinsProf - 0.5);

    sprintf(id, "h2%d", j);
    h2[j] = new TH2F(id, strCurrTitle[j], 
		     nbinsX, -0.5, nbinsX - 0.5,
		     nbinsY, -0.5, nbinsY - 0.5);
  }

  // second, fill all histos
  Long64_t nbytes = 0;
  if (debug>1) cout << " nentries " << nentries << endl;

  for (Long64_t i=0; i<nentries;i++) {
    if (debug>1) cout << " get entry i " << i << endl;
    nbytes += tree->GetEntry(i);
    if (debug>1) cout << " entry i " << i << " iSta " << iSta << endl;

    int iwafer = (iChip / 10000);
    int inWafer = (iChip % 10000);

    if (iwafer == iwaferlot) { // selected waferlot

      int icol = inWafer % nbinsX;
      int irow = inWafer / nbinsX;
      int irowRev = nbinsY - irow; // reverse row index to agree with DB plots

      Int_t binx = h2[0]->GetXaxis()->FindBin(icol); 
      Int_t biny = h2[0]->GetYaxis()->FindBin(irowRev); 

      for (j = 0; j<kNHistMax; j++) {
	h1[j]->SetBinContent(inWafer, fACurr[j]); 
	hp[j]->Fill(irowRev, fACurr[j]); 
	h2[j]->SetBinContent(binx,biny, fACurr[j]); 
      }
    }
  }

  gStyle->SetOptStat(0);
  // third, create all plots, and check cut info 
  if (debug>1) cout << " create canvas " << endl;
  TCanvas *c1 = new TCanvas("c1","c1");
  //  c1->SetLogz(1);
  if (debug>1) cout << " canvas created " << endl;

  for (j = 0; j<kNHistMax; j++) {
    if (debug>1) cout << " line " << __LINE__ << " j " << j << endl; 

    c1->cd(1);

    h1[j]->Draw();    
    c1->Modified();
    sprintf(id, "png/curr/wafer%d_h1_%s.png", iwaferlot, strCurr[j]);
    c1->SaveAs(id);

    hp[j]->Draw();    
    c1->Modified();
    sprintf(id, "png/curr/wafer%d_hp_%s.png", iwaferlot, strCurr[j]);
    c1->SaveAs(id);

    h2[j]->Draw("colz");    
    c1->Modified();
    sprintf(id, "png/curr/wafer%d_h2_%s.png", iwaferlot, strCurr[j]);
    c1->SaveAs(id);

  }

}