[Halld-offline] Standard ROOT TTree Format

[Paul Mattione]

As discussed during the previous offline software meeting, I've been developing a standard ROOT TTree format that the collaboration could use for all analyses of GlueX data.  This format is designed to work for the analysis of any reaction, and would provide an organized and easy-to-use representation of the data.  It's also designed so that C++ objects (mirroring DParticleCombo, etc.) can be created in ROOT from the TTree branches to provide object-oriented access to the data.  

I'm looking for feedback on the current design though.  To see how my proposal would look, I've created an example TTree and TSelector of b1pi events (using the b1pi_hists plugin) on the JLab CUE (ifarm1102) at:

/home/pmatt/GlueXTTree/hd_root.root (The tree is called "b1pi_Tree" and is located in the "b1pi" folder)

If you'd like to give the tree format a test-run on your own data/reaction, I've provided the source code in that same folder (copy and build the files in the corresponding directories).  The documentation for the format has been cleaned up a bit since the last meeting and is at:

https://halldweb1.jlab.org/wiki/index.php/Analysis_TTreeFormat

This format can be expanded over time to include more data as needed, but I'm trying to get the basics worked out now.  Is this format missing anything obvious that needs to be included?  We'll be discussing this again at the next offline software meeting (Wednesday), so if you're interested in this topic please take a look at it before then and let me know what you think.  Thanks!  

 - Paul