Re: Reusing the automatic histogram

Rene Brun (Rene.Brun@cern.ch)
Mon, 19 Apr 1999 14:23:28 +0000

Hi Bill,
I cannot reproduce your problem. Send me your file giving this problem.
I will investigate. Also, don't forget to specify the version number
and machine type.
However, I strongly suggest that you replace the statement:
h1->Delete();
by
delete h1;

Rene Brun

William Love wrote:
>
> Rooters
>
> I am trying to use in a loop the automatic binning feature of
> ntuple->Draw("x>>h1","selection")
>
> If I try to reuse h1 without deleting it the contents are replaced
> but the bins and limits are not recalculated which is no use. If
> I delete h1 before replacing it, new limits are computed but I get a
> segmentation violation.
>
> root [0] TFile f("straight3rd.root");
> root [1] stks->Draw("z>>h1","z>28 && z<32");
> Warning in <MakeDefCanvas>: creating a default canvas with name c1
> root [2] h1->Print();
> TH1.Print Name= h1, Total sum= 18409
> root [3] h1->Delete();
> root [4] stks->Draw("z>>h1","z>55 && z<60");
> root [5] h1->Print();
>
> *** Break *** segmentation violation
>
> Help?
>
> Bill Love