RE: [ROOT] TTree::Draw strange behavior ?

From: Philippe Canal (pcanal@popgtw.fnal.gov)
Date: Wed Jun 14 2000 - 22:41:31 MEST


Hi,

This problem as well as many of the related to the handling of
arrays and TClonesArrays in the TTree::Draw command should be 
corrected in the next release of ROOT (likely 2.25.00).

Philippe Canal.

> -----Original Message-----
> From: owner-roottalk@pcroot.cern.ch
> [mailto:owner-roottalk@pcroot.cern.ch]On Behalf Of Alberto Baldisseri
> Sent: Thursday, May 11, 2000 1:44 PM
> To: roottalk
> Subject: [ROOT] TTree::Draw strange behavior ?
> 
> 
> Hi rooters,
>     I like to use a TTree filled with a TClonesArray with the splitlevel
> = 1 option. Like in the macro
> tcl.C delivered with the ROOT distributions 2.24/04. I type :
> 
> root [0]> tcl.C(1)
> 
> to build the file tcl.root containing the TTree T. I found the following
> behavior :
> 
> 1) T.Draw("fX1[20]") and T.Draw("fX1[20]","tcl_>20") don't give the same
> result !
> In other words, the protection tcl_>20 against spurious data is
> MANDATORY, since
> plotting the 21th member of a table fX1[20] have no sense for events
> with tcl_<=20.
> There is a plan in ROOT to improve that and to avoid to put explicitly
> the condition
> tcl_>20 ? There is a technical problem around ? Since ROOT knows for
> each event
> how long is the table (variable tcl_) ?
> 
> 2) Another problem related araises when I put some other condition :
> 
> T.Draw("fX1[20]","abs(fX1[20]-0.1)<0.3&&tcl_>20") and
> T.Draw("fX1[20]","tcl_>20&&abs(fX1[20]-0.1)<0.3") dont give the same
> result !
> 
> I suspect (looking to some data of my experiment) that the good one is
> the first.
> 
> Anybody observe before those things ? Is all that normal ?
> 
> Regards,
> 
> Alberto
> 
> 
> --
> +-------------------------------+------------------------------------+
> | Alberto BALDISSERI            | Tel : (33-1) 69 08 93 33           |
> | DAPNIA/SPhN, Bat 703 pièce 42 | Fax : (33-1) 69 08 75 84           |
> | CEA Saclay                    | E-mail : a.baldisseri@cea.fr       |
> | F 91191 Gif-sur-Yvette cedex  |                                    |
> +-------------------------------+------------------------------------+
> 
> 
> 
> 



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