GlueX Offline Meeting, June 26, 2013

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GlueX Offline Software Meeting
Wednesday, June 26, 2013
1:30 pm EDT
JLab: CEBAF Center F326/327


  1. Announcements
  2. Review of minutes from the last meeting: all
  3. July 2013 Tutorial Planning for Workshop/Tutorial (all)
  4. Top-level build scripts (Mark)
  5. BCAL Update (Will)
  6. Data Challenge 2 (all)
  7. GEANT4 Status
  8. Mantis Bug Tracker Review
  9. Review of recent repository activity: all

Communication Information

Video Conferencing

Desktop Sharing

You can view the computer desktop in the meeting room at JLab via the web.

  1. Go to
  2. In the "join a meeting" box enter the Hall D code: 1833622
  3. Fill in the participant registration form.


To connect by telephone:

  1. dial:
  2. enter access code followed by the # sign: 1833622#


Talks can be deposited in the directory /group/halld/www/halldweb/html/talks/2013-2Q on the JLab CUE. This directory is accessible from the web at .


  • CMU: Will Levine, Paul Mattione, Curtis Meyer
  • IU: Matt Shepherd
  • JLab: Mark Ito (chair), David Lawrence, Simon Taylor, Georgios Vasileiadis, Elliott Wolin, Beni Zihlmann
  • Northwestern: Sean Dobbs
  • UConn: Alex Barnes[?], Richard Jones

Geant4 Conversion

Richard is ready to start. Mark will make a branch for Richard to use. Although there might be changes to the BCAL code and tracking, we agreed it was time to go ahead and start.

Planning for Analysis Workshop/Tutorial

Paul led the discussion.

A rather detailed draft agenda has been posted on the wiki.

  • Justin, Matt, and Paul M. have been doing planning over email.
  • Input data sets for each stage that requires one will be prepared in advance.
  • Justin generating 5 to 10 million Pythia events and working on training the BDT on them.
  • Matt suggested that we have an area of the subversion repository for the exercises and talks.
  • Work on the agenda will continue.
  • The registration page is up.
  • Coffee and cookies will be served. There will be an $18 registration fee.
  • Curtis has already purchased 16 GB USB memory sticks for the virtual machines.
  • Participants will be encouraged to install VirtualBox on their laptops in advance of the workshop. David also suggested posting a link to the VirtualBox download site.
  • The disk image will be available for folks who cannot attend live or for future use.
  • We will be using Xubuntu 12.04 LTS.

Top-level build scripts

Mark plugged his scripts to build the entire GlueX software complex from scratch on various flavors of Linux, in including installing prerequisite packages from the relevant repositories. See his wiki page for details.

BCAL Update

Will showed recent studies on how charged pions are seen by the BCAL, including issues with matching of charged tracks to BCAL clusters. See his slides for details.

  • Simon told us that the matching criteria are based on empirical distributions of the miss distance between cluster and track location at the face of the BCAL.
  • There is a long tail in the time difference distribution, even if the matching criteria are tightened, out to 10 ns and beyond. This needs to be understood.

Data Challenge 2

Mark has just started resurrecting his scripts from the first data challenge. Not much to report there.

We discussed what needs to be done before we can start.

  • Further BCAL reconstruction improvements
    • Curtis wondered about solving the timing tail problem that Will mentioned and the "curving" of the shower profile seen by Andrei Semenov. These problems do not have solutions in hand at present. We will have to wait and see if we can expect them to come on fast enough to include.
    • Matt suggested that one way to go would be to save the individual BCAL hits in the REST format so that we could either re-do the reconstruction or use the hits in a future algorithm that requires access to individual hits. We discussed whether these kind of studies need to be included in the data challenge or not.
  • Electromagnetic background
    • Although it is easy to turn this background on, David cautioned that using a time window large enough to fill the drift time window in the tracking chambers might slow down execution by a lot. He has already implemented a system where a relatively small number of pure background events can be mixed into the events of interest at the hit level. This problem will need to be revisited before we start.
  • Noise hits in the BCAL
    • David told us this is easily turned on.
  • Tracking improvements
    • Simon told us that there are a few improvements he is working on that we might want to include.
  • Expanding photon energy range
    • This is done with a simple configuration parameter change.
  • Tagging trigger results, both for level 1 and 3.
    • We need to look back and see if this has been done already. If not, we should include it.

Curtis proposed that we set a goal of four weeks from today to make decisions on these issues and freeze the code. We thought that that would be a good goal.

Online Data Challenge

David, Elliott, and Sean are working on generating raw data in EVIO format from Monte Carlo events using the real translation tables that Dave is developing. These tables based on Fernando's spreadsheets. These will be used to test the online data pathway, including monitoring, RootSpy, and possible transfer to the tape library.

Software Review News

Nothing new.