scanEff( char *conf="D") {
  // const int mxH=10;
  // TH1F *hEff[mxH];
  int nh=0;
  gStyle->SetPalette(1,0);

  TString inpP="out"; inpP+=conf;inpP+="/";

  
  TString outF="scan";outF+=conf;
  outF+=".hist.root";
  hf=new TFile(outF,"recreate");

  printf("\n Histo saved -->%s<\n",outF.Data());

  c=new TCanvas("aa","aa",600,600); 
  c->Divide(2,2);

  char *core="elePt";
  char *zver="Zm30";
  int jpt;
  int jz;
  int tq=1;

  for(tq=0;tq<2;tq++ ) 
  for(jz=0;jz<3;jz++ ) {
    TH2F *h2d=0;
    if(jz==0) zver="Zm30";
    if(jz==1) zver="Z0";
    if(jz==2) zver="Zp30";

    for(jpt=1;jpt<=10 ;jpt++) {
      int PT=5*jpt;
    
      char name[100];
      sprintf(name,"%s%d%s",core,PT,zver);
      printf("name=%s=\n",name);
      
      fd=new TFile(inpP+name+".hist.root");
      
      TH1F *h=doEff(fd,nh,tq); assert(h);
      //c->cd(nh+1);    h->Draw();
      TString tit=h->GetTitle();     tit="  "+tit;
      tit=name+tit;    h->SetTitle(tit);
      
      TString tit0=zver;
      if(tq==0) {
	tit="Track eff,";
	tit0="trEff_"+tit0;
      } else {
	tit="Charge eff_";
	tit0="qEff_"+tit0;
      }
      tit+=zver;
      
      ax=h->GetXaxis();
      if(h2d==0) {
	h2d=new TH2F(tit0,tit+" vs. eta & pt; gen #eta; gen PT (GeV)",
		     ax->GetNbins(),ax->GetXmin(),ax->GetXmax(),
		     20,1.25,51.25 );
      }
      
      int ib; 
      for(ib=1;ib<=ax->GetNbins();ib++) { 
	h2d->SetBinContent(ib,jpt*2,h->GetBinContent(ib));
      }      
      // assert(nh<mxH);    hEff[nh]=h;
      nh++;
      
    }
    if(0) { 
      c->cd(4);
      c=new TCanvas("aa","aa",400,450);
      h2d->Draw("colz");
     gStyle->SetOptStat(0);
    }
    hf->cd();
    h2d->Write();
  }
  
}

//===============================
TH1F *doEff(TFile *fd, int xx, int type=0){
  //  c=new TCanvas("aa","aa",700,800); 
  //  c=new TCanvas("aa2","aa2",400,500);
  // c->Divide(1,2);
  
  
  char *name1="gEtaG";
  char *name2="mEta";
  if(type!=0)name2="mqEta";
 

  TH1F* h1=(TH1F*)fd->Get(name1); assert(h1);  
  TH1F* h2=(TH1F*)fd->Get(name2); assert(h2);  
  
  //  c->cd(1);   h1->Draw();
  // h2->Draw("same"); h2->SetLineColor(kRed);
  
  TH1F* hef=(TH1F*) h1->Clone();
  hef->SetTitle("efficiency vs. #eta; generated #eta; eff ");
  hef->Reset();
  TString tt2="aaa"; tt2+=xx;
  hef->SetName(tt2);
  int nb=hef->GetNbinsX();
  printf("------- nh=%d\n",xx);
  int ib; 
  for(ib=1;ib<=nb;ib++) { // loop over all histo bins, starts from 1 - how silly!
   
    float x=h1->GetBinCenter(ib);
    float y1=h1->GetBinContent(ib);
    float y2=h2->GetBinContent(ib);
    if(y1<=0.) continue;

    float eff=y2/y1;
    float effEr=sqrt(y2*(y1-y2)/y1)/y1;
    printf("bin=%d x=%.2f y1=%.0f y2=%.0f  eff=%.2f +/-%.2f\n",ib,x,y1,y2,eff,effEr);
    hef->SetBinContent(ib,eff);
    hef->SetBinError(ib,effEr);
  }
  
  // c->cd(2);    hef->Draw();
  return hef;
}