[ROOT] Re: Different TH2 projection errors in ROOT and PAW

From: Rene Brun (Rene.Brun@cern.ch)
Date: Tue Sep 10 2002 - 23:24:32 MEST


Hi Stanislas,

Thanks for reporting this case with TH2::ProjectionX,Y.
The problem is now fixed in the CVS version.

Rene Brun

On Tue, 10 Sep 2002, Stanislav NESTEROV wrote:

> 
>     Hi, Rene,
>     Again about PAW and ROOT compatibility...
>     Recently I made some projections of 2d-histogramms, and noticed that 
> in case of 2d-histogram with errors projected histograms in ROOT and PAW 
> have different errors. I think PAW makes error calculation in this 
> case more correctly than ROOT: ROOT actually calculates error bars without 
> any respect to errors in original 2d-histogramm.
> 
>    Projection in PAW made by:
>     PAW >  prox 8399
>     PAW >  hi/proj 8399
>     PAW >  hi/pl   8399.prox
> 
>    Projection in ROOT made by:
> 
>     root [1]  h8399->ProjectionX("_px",-1,-1,"e");
>     root [2]  h8399_px->Draw();
>    
>    May be important: I've used 2d-histograms with errs, produced via HBOOK 
> package, then convert them into ROOT file by means of h2root utility. But 
> I've checked the code of H2ROOT and there're lines that convert 2d-errors 
> from PAW to ROOT...
> 
> (ROOT-3.03/08 AFS-version for 7.2 redhat)
> 
> 			Best regards,
> 					Stanislav.
> 



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