TAxis::SetRangeUser versus TH1::SetAxisRange

ROOT
1

The fixes which are present in the TAxis::SetRangeUser method are missing in the TH1::SetAxisRange method.

2

Thanks Wile! This is for @moneta

3

Hi,
I guess you are referring to this code:

  // fixes for numerical error and for https://savannah.cern.ch/bugs/index.php?99777
  if (GetBinUpEdge(ifirst) <= ufirst ) ifirst += 1;
  if (GetBinLowEdge(ilast) >= ulast ) ilast -= 1;
  SetRange(ifirst, ilast);

I am not sure it is really useful. Do you have an example where it is really needed ?
Unfortunately the link to the Savannah item is lost

Cheers

Lorenzo

4 
{
  TH1F *h = new TH1F("h", "h", 100, 0., 100.);
  h->GetXaxis()->SetRangeUser(0., 100.);
  std::cout << h->GetXaxis()->GetLast() << "\n";
  h->SetAxisRange(0., 100.);
  std::cout << h->GetXaxis()->GetLast() << "\n";
}
5

Hi,
Thanks for the example. This is not a fix due to a numerical error, but a bug in Taxis::SetAxisRange when the upper value is equal to the bin upper edge. yes we need to have:

if (GetBinLowEdge(ilast) >= ulast ) ilast -= 1;

instead I am not sure if the other check is really needed, however is not harmful, so we could keep it

Lorenzo