Re: tree.GetEntries() (nothing serious, but,..)

From: Rene Brun (Rene.Brun@cern.ch)
Date: Mon Dec 20 1999 - 11:04:19 MET


Hi Pasha,
You are right about TTree::GetEntry.
The important thing is that the member fEntries in both TH1
and TTree is stored as a double.

Rene Brun

On Sun, 19 Dec 1999, Pasha Murat (630)840-8237 FNAL (630)859-3463 home wrote:

> it might make sense to have an input parameter of 
> TTree::GetEntry (and also TChain::GetEntry) being of the same 
> type (Stat_t) as the return type of TTree::GetEntries. 
> Right now they are different:
> 
>     virtual Stat_t GetEntries()
>     virtual Int_t  GetEntry(Int_t entry = 0, Int_t getall = 0)
>                              ^
> so it is not quite clear how one could use the fact that 
> TTree::GetEntries returns `double'.
> 						best, Pasha                            
> 
> > Rene Brun wrote:
> 
> > Dear Selim,
> > As you say, "you did not see the point"
> > How would you proceed if you have an histogram, a Tree
> > or likely a TChain with more than 2 billion entries ?
> >
> > Because longlong is not yet a portable data type,
> > the only way to survive is to do the job with a double.
> >
> > Rene Brun
> >
> > On Fri, 17 Dec 1999, Selim Issever wrote:
> > 
> > > Dear concerned,
> > > 
> > > line 70 of my mo.C is:
> > > Int_t sNumEntries = sTree->GetEntries(); 
> > > 
> > > but while compiling I get:
> > > mo.C:70: warning: initialization to `int' from `double'
> > > 
> > > It works anyway,.. but does it make sense to give the number of entries back
> > > as a double? 1.5 entires?! *shrug* but maybe I just dont see the point,..
> > >
> 



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