[d2n-analysis-talk] Analyzer output: histograms written to ROOT files

[Brad Sawatzky]

On Fri, 29 Jan 2010, Diana Parno wrote:

Still working on the mystery VDC histos.  I stripped all of the vdc
stuff out of libBigBite but they still show up in the rootfile!?!
Looking some more...

[ . . . ]
> In a more straightforward ROOT question, I'm also curious as to what the 
> meaning is behind having multiple copies of a single histogram (e.g. 
> Lenroc16;1 and Lenroc16;2 which both show up on a .ls command). Do these 
> represent the way ROOT handles a memory overflow when writing a huge 
> histogram? Do they represent the same histogram written multiple times for 
> some reason? Or is it something else entirely?

Seems to be how TFile::Write(), which is inheirited by TH1::Write(),
handles duplicate calls with a non-unique key.  I think it is probably a
bug in THaDecData.  The write routine is being called multiple times
when it should only be called once.

See also:
  http://root.cern.ch/drupal/content/saving-histograms-disk

-- Brad

-- 
Brad Sawatzky, PhD <brads at jlab.org>  -<>-  Jefferson Lab / Hall C / C111
  Ph: 757-269-5947 -<>- Pager: 757-584-5947 -<>- Fax: 757-269-7848
The most exciting phrase to hear in science, the one that heralds new
  discoveries, is not "Eureka!" but "That's funny..."   -- Isaac Asimov