RE: [ROOT] Array Arguments of tree->Branch(....)

From: Philippe Canal (pcanal@fnal.gov)
Date: Mon Jul 14 2003 - 20:04:45 MEST 

Hi Zaldy,

You are simply missing the statement:

	f.Write(); 

Which will save the File information.  You can actually simply replace
	tree->Write();
by 
	f.Write();

Cheers,
Philippe.

-----Original Message-----
From: zaldy [mailto:zaldy@neutrino.kek.jp]
Sent: Monday, July 14, 2003 1:04 PM
To: Philippe Canal
Cc: roottalk@pcroot.cern.ch
Subject: RE: [ROOT] Array Arguments of tree->Branch(....)



Dear Philippe,

Sorry to bother.
I did wrote a small class script which is very similar to my original 
code:
http://neutrino.kek.jp/~zaldy/root_work/MyRootFaq/TT.hh
http://neutrino.kek.jp/~zaldy/root_work/MyRootFaq/TT.cc
http://neutrino.kek.jp/~zaldy/root_work/MyRootFaq/Test.cc
http://neutrino.kek.jp/~zaldy/root_work/MyRootFaq/Report_Branch_Array_Arg1.txt

Unfortunately, I was not able to understand very well.
I tried this for non-array arguments(well no segmentation problem), but 
the file size of the rootfile is zero.

May I know some explanation about this?

Thanks.


Zaldy N.


> Hi,
> 
> The reason is that 'TOTAL' is a variable of your program. This is NOT
> accessible by the tree or the branch object.  Hence the problem which is
> diagnotiqued by the error message:
> 
>    Error in <TBranch::TBranch>: Illegal leaf:AA/AA[TOTAL]/F
> 
> We recommend that you do not use this style of branches (it has a few
> pitfalls that are hard to over-come).
> Instead we recomment using a class.  This can be trivially done by written a
> class definition and compiling it with ACLiC.
> 
> Cheers,
> Philippe.
> 
> -----Original Message-----
> From: owner-roottalk@pcroot.cern.ch
> [mailto:owner-roottalk@pcroot.cern.ch]On Behalf Of zaldy
> Sent: Monday, July 14, 2003 12:04 PM
> To: roottalk@pcroot.cern.ch
> Subject: [ROOT] Array Arguments of tree->Branch(....)
> 
> 
> 
> Dear ROOTers,
> 
> I'd like to understand and learn how to create a tree with an array
> branch. I read the Tutorial section (tree3.C).
> 
> But why does the ff. line produces a segmentation problem/error messages:
> --------------------------------------------------------
> ........
> int TOTAL = 2;
> float AA[TOTAL];
> TTree * tree = new TTree("tree","What a nice Tree");
> tree->Branch("AA",AA,"AA[TOTAL]/F");
> ......
> --------------------------------------------------------
> Pls see URLs:
> http://neutrino.kek.jp/~zaldy/root_work/MyRootFaq/Report_Branch_Array_Arg.tx
> t
> http://neutrino.kek.jp/~zaldy/root_work/MyRootFaq/test.cc
> 
> while:
> ---------------------------------------------------------
> .........
> float AA[2];
> TTree * tree = new TTree("tree","What a nice Tree");
> tree->Branch("AA",AA,"AA[2]/F");
> --------------------------------------------------------
> dont.
> 
> Am using ROOTV: 3.04/02
> gcc 2.91.66
> 
> 
> Thank you.
> 
> --------------------------------------------------------
>                    Zaldy A. Nawang
>                    PS Users Room 2
>                    Yon Gokan,
>                    E362, Neutrino Group,
>                    IPNS, KEK,
>                    Japan
> 
>                    e-mail: zaldy@neutrino.kek.jp
>                    Tel. No. : (81) 029864 - 5387
> --------------------------------------------------------
> 
> 
> 

-- 

--------------------------------------------------------
                   Zaldy A. Nawang 
                   PS Users Room 2
                   Yon Gokan, 
                   E362, Neutrino Group, 
                   IPNS, KEK, 
                   Japan 
                    
                   e-mail: zaldy@neutrino.kek.jp
                   Tel. No. : (81) 029864 - 5387
--------------------------------------------------------

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