// box with polynomial filling
Double_t f1_xboxe(double *x, double *par){
  double xx    = x[0];
  double wx    = 1. - par[4]*TMath::Power(xx+par[5],2);
  double xboxe = par[0]*0.25*(1.+TMath::Erf(( xx+par[1]-par[3])/par[2]))
                            *(1.+TMath::Erf((-xx+par[1]+par[3])/par[2]));
  return xboxe*wx;

  /* 
       common/pawpar/p(6)
       real wx 
       wx=1.-p(5)*(x+p(6))**2
C       wx=1.
       xboxe=p(1)*0.25*(1.+erf(( x+p(2)-p(4))/p(3)))
     &                *(1.+erf((-x+p(2)+p(4))/p(3)))
       xboxe=xboxe*wx
  */
}

void fit_ybox(TString hname)
{
 TH1 *h1;
 TH2 *h2;
 h1=(TH1 *)gROOT->FindObjectAny(hname);
 if(NULL != h1){
   TAxis *xaxis = h1->GetXaxis();
   Double_t Ymin= xaxis->GetXmin();
   Double_t Ymax= xaxis->GetXmax();
   TF1 *f1=new TF1("YBox",f1_xboxe,Ymin,Ymax,6);
   Double_t yini=(h1->GetMaximum()+h1->GetMinimum())*0.5;
   f1->SetParameters(yini,Ymax*0.8,2.,-1.,0.,0.);
   h1->Fit("YBox");

   double res[10];
   double err[10];
   res[9]=f1->GetChisquare();

   for (int i=0; i<6; i++)
   {
     res[i]=f1->GetParameter(i);
     err[i]=f1->GetParError(i);
     //cout << " FPar "<< i << ": " << res[i] << ", " << err[i] << endl;  
   }
   cout << "YBox Fit of "<<hname<<" ended with chi2 = "<<res[9]
	<< Form(", strip length %7.2f +/- %5.2f, position resolution %7.2f +/- %5.2f at y_cen = %7.2f +/- %5.2f",
		2.*res[1],2.*err[1],res[2],err[2],res[3],err[3])
	<<endl;
 }  
}