RE: How to access the value of branch variables?

From: Sudeep Chatterji <>
Date: Sat, 5 Feb 2005 11:48:54 +0100

Dear Rene,

   When I am calling Analysis->SetMakeClass(1); as suggested by you before calling SetBranchAddress, I am getting segmentation fault. I am attaching the log file with this mail. Regards,

-----Original Message-----

From:	Rene Brun
Sent:	Fri 2/4/2005 9:13 AM
To:	Sudeep Chatterji
Subject:	Re: [ROOT] How to access the value of  branch variables?
Hi Sudeep,

By default when you create a top level branch with sub branches, ROOT assumes that you will give the address of the top level branch to read the sub-branches into the original class/structure. If you want to read a sub-branch into your own variable, you must call

before calling SetBranchAddress

Rene Brun

Sudeep Chatterji wrote:
> Dear Rooters,
> I am using ExRootAnalysis for reconstructing photons. The parameter
> structure is given below:
> Analysis (tree)
> {
> Photon_size
> Photon (Branch)
> {
> Photon.CalPT
> Photon.CalEta
> Photon.CalPhi
> Photon.VtxZ
> Photon.Isolation
> Etc.
> }
> }
> I am able to access Photon_size variable in the rootscript file by the following command:
> Analysis->SetBranchAddress("Photon_size",&Photon_size);
> But, when I am trying the same with the Photon branch variables(as shown below), I am unable to do so.
> Analysis->SetBranchAddress("Photon.CalPT",Photon_CalPT);
> Please suggest something in this regard.
> Regards,
> Sudeep Chatterji

Received on Sat Feb 05 2005 - 11:49:00 MET

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