//--------------------------------------------------------
poissonup(double xmu=3.,int nent=1000000){
  cout << "This is a subsequent call that refills the histogram" << endl;
  cout << "The mean of the Poisson distribution is " << xmu << endl;
  cout << "The number of entries is " << nent << endl;
h1->Reset();
int i;
TRandom3*r=new TRandom3(0);
for (i=0; i<nent;i++){h1->Fill(r->Poisson(xmu));}
 gStyle->SetOptStat(220002210);
h1->Draw();
}
//-gPad->SetLogy(1); toggles to logarithmic y scale--------