Re: [ROOT] Lost errors for TH2 as read from a h2root-converted file

From: Rene Brun (Rene.Brun@cern.ch)
Date: Sat Nov 03 2001 - 23:07:11 MET


Hi Kay,

Thanks for noticing this point. Now fixed in 3.02/03

Rene Brun

On Sat, 3 Nov 2001, Kay Ulbrich wrote:

> Hello,
> 
> when reading a *.root-file converted by h2root from an hbook-file, the
> errors for 2-dimensional histograms seem to get lost, because
> TH2::GetBinError(...) renders the square root of the entries, whereas
> the corresponding histograms in the hbook-file contained different
> errors. The same does not seem to happen for TH1-instances. 
> 
> Now, I store the error-histograms separately in the hbook-file and then
> force the errors for the 2-dim histograms under question to the
> associated entries in them under ROOT using TH2::SetBinError(...), but
> surely this is not the most elegant way to do it, because it doubles
> the number of histograms to be written by the hbook-generating
> program. 
> 
> Has this been encountered before and is it the consequence of a
> possible mistake of mine?
> 
> Thanks for help,
> Kay
> 
> -- 
> Kay Ulbrich
> Institut fuer Strahlen- und Kernphysik, Universitaet Bonn
> Nussallee 14-16 / D-53115 Bonn / Deutschland
> Tel.: 0228-73-1768 / E-Post: ulbrich@iskp.uni-bonn.de
> 



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