Re: [ROOT] Chain projection

From: Rene Brun (Rene.Brun@cern.ch)
Date: Mon Mar 03 2003 - 12:08:59 MET


Hi Ciro,

I cannot reproduce this problem with the old version 3.02/07.
Is chain.Draw("180.*fTheta/3.1415") featuring the same problem?

I need more  information like the result of chain.Print().

I also suggest to move to a more recent version such as 3.05/02

Rene Brun

On Fri, 28 
Feb 2003, Ciro Bigongiari wrote:

> 
> 
> Hi rooters,
> 
> I tried to project a chain on a predefined histo without success.
> Here is what I did:
> 
> {
>    gROOT->Reset();
> 
> //   Create the chain as above
> 
>    TChain chain("Events")
>    chain.Add("Pseudoelectron_0_0_7_1000to1009_w0.root");
>    chain.Add("Pseudoelectron_0_0_7_1130to1139_w0.root");
> 
> //   Create an histogram
> 
>    TH1F *helectron = new TH1F("helectron","Triggered electrons",50,0,5);
> 
> //   Project the chain
> 
>    chain.Draw("180.0*fTheta/3.1415 >>+ helectron ");
> 
> //  Draw the histogram
> 
>    helectron ->Draw();
> }
> 
> 
> The histogram I got seems to contain only the events in the second file.
> 
> 
> 
> My data are:
> 
> PC Pentium IV
> Linux RedHat  7.2
> ROOT  Version   3.02/07   7 February 2003
> 
> What  did I do wrong ?
> Thanks a lot in advance.
> 
> Regards, ciro
> 



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