[d2n-analysis-talk] How to test ROOT/5.22 on d2n.jlab.org

[Brad Sawatzky]

Be sure to read and follow all of the instructions below.  If your code
attempts to pull in .so libraries compiled against the stock 5.18
version of ROOT there will be problems.  The root-setup.sh script
takes care of pointing the environment vars for both the analyzer and
ROOT stuff.  Note that the code in your replay directory may attempt to
link in other libs though (see the last paragraph).

It would be helpful if you folks could try this out with your standard
replay codes and report back on Thursday.  If it's working for everyone
then I'll make this version the default.

The background is that Diana seems to have hit a bug in how ROOT 5.18
handles cloned TChains with her farm replay code...  I ended up
recompiling ROOT 5.22 and our analyzer on d2n.jlab.org.

You can try it out by sourcing this file instead of the usual one:
  /usr/local/d2n_analysis-root5.22/d2n/root-setup.sh
That will point you at the newer version of root and the associated d2n
analyzer binaries.

If you want to use the new ROOT for regular replays (ie. ones that pull
in libBigBite.so, etc), then you will have to make sure those libraries
point to the updated d2n libs too.  I ended up modifying my rootlogon.C
to use $d2n_root:
  /home/brads/replay/rootlogon.C
I can then remove the *.so files in my replay dir and they will be
automatically pulled from the correct location based on which
root-setup.sh is sourced.

-- Brad

-- 
Brad Sawatzky, PhD <brads at jlab.org>  -<>-  Jefferson Lab / Hall C / C111
Ph: 757-269-5947  -<>-  Fax: 757-269-5235  -<>- Pager: brads-page at jlab.org
The most exciting phrase to hear in science, the one that heralds new
  discoveries, is not "Eureka!" but "That's funny..."   -- Isaac Asimov