Re: [ROOT] Problems with TSelector

From: Rene Brun (Rene.Brun@cern.ch)
Date: Thu Dec 18 2003 - 18:39:39 MET


Christian,

Which version of Root are you using?
see : http://root.cern.ch/root/roottalk/RoottalkRules.html

In case you use 3.05/07 with a chain referencing remote files,
upgrade your version of Root.

Rene Brun

Christian Vogel wrote:
> 
> Hi roottalk,
> 
> I tried to make a really primitive analysis in root using a TSelector
> (and two derived classes) because I wanted to encapsulate stuff I have
> to do several times in a intermediate class... And I want to iterate
> over several files in a TChain. My selector-hierarchy looks like:
> 
> TSelector
>   |
>   +-- GsiSelector  (load stuff from branches, later: do cuts, prepare
>         |           intermediate values...)
>         |
>         +-- gsi_calc_pedestals
>         |
>         +-- other stuff
> 
> Now in principle, I think it works, but it seems to call Notify() at
> strange locations. Possibly it's doing strange things which also slow
> everything down quite a lot. If I run the code[*] it does the following:
> 
> GsiSelector() - constructor is called (fine)
> GsiCalcPedestals() - constructor is called (fine)
>  Begin() is called (fine), this saves the TTree* in fTree member variable
>  Notify() is called (fine)
>  Notify() is called AGAIN. WHY? <---------
> 
>  --->  for all Events in the first file
>  |  ProcessCut/ProcessFill is called for events (fine)
>  |   |
>  +---+
> 
>  Notify() is called (fine), new file
>  Notify() is called AGAIN. WHY? <------
> 
>  ProcessCut/ProcessFile for first event in second file
> 
>  Now, Notify() is called for EVERY EVENT in the second file.
>  Things get very, very, very slow.
> 
> Have I done something completely wrong and/or stupid?
> 
>         Chris
> 
> [*] you can have a look here:
>         http://pi2.physik.uni-erlangen.de/~vogel/gsi_analysis_root/
> 
> --
> There are three types of people in the world; those who can count,
> and those who can't.



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