void make_root(int VD,  int VB){

  char line[355];
  char line1[20] = ".....EEEEE";
  char str[2]= {'\0','h'};
  int count = 1;
  char cid[200];


  const int NX=17;
  const int NY=115;
  char hname[30] ;
  TH2F *hEx, *hEy;
  if(VB==0) {
  sprintf( hname, "Ex_FEM_%d_%d",VD,VB);
  if(VD<0) sprintf( hname, "Ex_FEM_M%d_%d",-VD,VB);
  hEx = new TH2F(Form("%s",hname),Form(
    "FEM Ex for VFD=%dV ",VD),NX,0,NX,NY,0,NY);
  sprintf( hname, "Ey_FEM_%d_%d",VD,VB);
  if(VD<0) sprintf( hname, "Ey_FEM_M%d_%d",-VD,VB);
  hEy = new TH2F(Form("%s",hname),Form(
    "FEM Ey for VFD=%dV",VD),NX,0,NX,NY,0,NY);
  }
  
  if(VD==0 && VB==100) {
  sprintf( hname, "Ex_FEM_%d_%d",VD,VB);
  hEx = new TH2F(Form("%s",hname),Form(
    "FEM Ex for VB=%dV",VD),NX,0,NX,NY,0,NY);
  sprintf( hname, "Ey_FEM_%d_%d",VD,VB);
  hEy = new TH2F(Form("%s",hname),Form(
    "FEM Ey for VB=%dV",VD),NX,0,NX,NY,0,NY);
  }

  double X[NX][NY], Y[NX][NY], Potential[NX][NY], E[NX][NY],j[NX][NY], 
  PDens[NX][NY], Ey[NX][NY], Ex[NX][NY], Jx[NX][NY], Jy[NX][NY], 
  Epsi[NX][NY], Rho[NX][NY], dummy; 
  ifstream fin1("FEM_dummy.txt");
  fin1.getline(line, sizeof(line));
  for (int k=0; k<NX; k++){
  for (int i=0; i<NY; i++){
    fin1 >> X[k][i]>>Y[k][i]>>dummy>>dummy>>Ex[k][i]>>Ey[k][i]>>E[k][i]>>dummy>>dummy>>dummy>>dummy; 
    E[k][i] = E[k][i]/100.;
    Ex[k][i] = Ex[k][i]/100.;
    Ey[k][i] = Ey[k][i]/100.;
//----for SCT simulation, x=0 is at the cell edge, thus ix=m-k and Ex-->-Ex
    int ix = NX-1-k;
    hEx->Fill(ix,i, -Ex[k][i]);
    hEy->Fill(ix,i, Ey[k][i]);
 //   cout <<"k,i="<<k<<" "<<i<<" x,y="<<X[k][i] << " "<<Y[k][i]
 //  <<" Ex="<<Ex[k][i] <<" Ey="<<Ey[k][i]<<endl; 
  }
  } 

  for(int ix=0; ix<NX; ix+=16) {
  
  for(int iy=0; iy<NY; iy+=10) {
  double y=iy*2.5, x=ix*2.5, xold=(NX-1-ix)*2.5;
 // cout<<ix<<" "<<iy<<" (xold->x,y)=("<<xold<<"->"<<x<<","<<y<<")\t"<<
 //   hEx->GetBinContent(ix+1,iy+1)<<"\t"<<hEy->GetBinContent(ix+1,iy+1)<<endl;
}}

sprintf( hname, "FEM_%d_%d.root",VD,VB);
if(VD<0)sprintf( hname, "FEM_M%d_%d.root",-VD,VB);
TFile file(hname,"recreate");
TObjArray Hlist(0); // create an array of Histograms
Hlist.Add(hEx);
Hlist.Add(hEy);
Hlist.Write();
//Hlist.Write();

  return;
}