[ROOT] Reading TChain into memory

From: Mike Miller (miller@star1.physics.yale.edu)
Date: Mon Dec 09 2002 - 17:12:07 MET


Hi all, I have another problem reading a series of TTree objects as a
TChain in compiled code (root 3.03.09).  I have a tree in each file and
that tree has 4 branches, I read 3 of the 4 branches.  I have explicitly
deactivated the one branch I don't read and activated the 3 branches I do
read.  I've verified that I use SetBranchAddress correctly and the the
information I read into memory is fine.  The problem is that the call to
TChain::GetEntry(int, int) dies on the last entry of the first file in the
chain.  The first file has 2657 entries, so I'm assuming that means that
entries [0,2657) are valid, so that a call to GetEntry(2657) should get
the 0th entry of the second file.  If I use TChain::GetFile() to look at
the pointer to the current file, I see that the file pointer isn't
changing until I call GetEntry(2658).  Does this mean that the valid range
is [0,2657]?

Regardless, if I try to read more than one branch at a time, i get a 
seg-fault when I cross the boundary between the first and second file 
in the TChain.  This used to work for me in an older root version 
(3.02.0x).  How can I fix this?  Thanks, Mike

-- 
Michael L. Miller (Yale Physics) michael.miller@yale.edu

Seattle:	206.543.2908	EPE group, 2nd floor physics.
BNL: 		631.344.8342	Building 118 Yale Software
Yale:   	203.432.6615	Room 301 WNSL



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