RE: [ROOT] two trees

From: Philippe Canal (pcanal@fnal.gov)
Date: Sun Oct 06 2002 - 20:38:58 MEST 

Hi,

You can create 2 chains, one for the header, one for the data and make one
chain a
friend of the other.

	TChain header("header");
	TChain data("data");
	header->AddFriend(&data);

Cheers,
Philippe

-----Original Message-----
From: owner-roottalk@pcroot.cern.ch
[mailto:owner-roottalk@pcroot.cern.ch]On Behalf Of Mariusz Sapinski
Sent: Sunday, October 06, 2002 7:22 AM
To: roottalk@pcroot.cern.ch
Subject: [ROOT] two trees



 Hello Rooters,

 i got plenty of root-files with two trees each: event and header. I must
have two because in the header i got numbers which are calculated during
production of the file so header is written at the end of writting a file.
 I would like to analyse these files in a chain. So i'd like to create a
TChain. But a single TChain is a chain of one kind of tree objects eg.

  TChain data("data");

 And i need information from header also. If i got one file, i do
AddFriend and use variables from header. But how to proceed in my case?
And i got 10000 records in event and one in header (per run).

 Maybe i can analyse files somehow in the loop? But how to do this?

  Regards,

            Mariusz Sapinski

This archive was generated by hypermail 2b29 : Sat Jan 04 2003 - 23:51:12 MET