[Halld-offline] non-reproducibility study

[Mark Ito]

Folks,

Ran 1000 short jobs using the latest DC2 tags.

   tags/hdds-dc-2.1
   tags/sim-recon-dc-2.4

No EM background, 1000 events per job, saving the smeared raw data 
(hdgeant_smeared.hddm). Then I ran the same hd_root again against the 
saved smeared raw data.

Doing a diff on the dana_rest output:

differ = 994
identical = 6

I then dumped the hddm into xml form and diffed the output for a dozen 
pairs. Find the results at

   https://halldweb1.jlab.org/talks/2014-1Q/diffhddm.txt

You can see that the differences are not that big. You can tell that the 
same event was analyzed in iteration 1 and iteration 2. Close but no 
cigar. I could look at more files if that is of interest to anyone.

The rest files and the root files are at JLab in

   /volatile/halld/home/gluex/proj/dc_02_1
   /volatile/halld/home/gluex/proj/dc_02_2

Each of these directories has a rest directory and a hd_root directory. 
1 and 2 indicate the original run and the re-run respectively, of 
course. Compression was off and there are no short rest files.

Hope this helps someone. Not sure what my next step should be. 
Suggestions welcome.

   -- Mark