GlueX Offline Meeting, July 25, 2012

From GlueXWiki
Jump to: navigation, search

GlueX Offline Software Meeting
Wednesday, July 25, 2012
1:30 pm EDT
JLab: CEBAF Center, F326/327


  1. Announcements
    1. Data Challenge Meetings
    2. Scientific Computing Survey
    3. No more software sessions in Tracking Meetings (by default)
  2. Review of minutes from the last meeting: all
  3. Reconstruction sub-group reports
    1. Calorimeters
    2. Tracking
    3. PID
  4. Action Item Review
  5. Review of recent repository activity: all

Communication Information

Video Conferencing


Talks can be deposited in the directory /group/halld/www/halldweb/html/talks/2012-3Q on the JLab CUE. This directory is accessible from the web at .



  • CMU: Will Levine, Curtis Meyer
  • IU: Ryan Mitchell, Matt Shepherd
  • JLab: Mark Ito (chair), Manuel Lara, David Lawrence, Paul Mattione, Elton Smith, Simon Taylor, Elliott Wolin, Beni Zihlmann


  • Data Challenge Meetings have started on alternate Mondays at 1:30 pm.
  • Mark urged us to participate in the Scientific Computing Survey.
  • There will be no more (default) software sessions as part of the bi-weekly Tracking Meeting.
  • David and Elliott have started work on translation tables. If you have thoughts send them along. A proposed format was circulated on the Offline email list.

Review of Minutes from Previous Meetings

Offline Meeting

We reviewed the minutes from the July 11th meeting.

  • Paul reported that he thinks all work has been done for now on the REST format. We can start using it in production.
  • Simon made the promised changes in the default track hypotheses generated:
    • Positive tracks: pi, K, p
    • Negative tracks: pi, K

Data Challenge Meeting

We looked at the minutes of the July 16th meeting without significant comment.

Reconstruction Sub-Group Reports


David has been working on putting more realism in the BCAL smearing.

  • Full electronic pulse shape are generated, with dark hits.
  • Changes have been made to hdgeant and mcsmear. They are currently disabled by pre-processor directives.
  • The unsmeared file is much larger; mcsmear is four times slower for single photon events
  • hdgeant is about three times slower than mcsmear previously.
  • David will give a presentation on this work at a future meeting.


Simon gave a report:

  • One final, additional swim over reference trajectory eliminated.
  • The straight line fitting for alignment of the chambers is working.
    • Working with an algorithm to adjust parameters of each wire plane.
    • Allows for rotation and shift of entire plane.
    • Some convergence difficulties being worked on presently.
  • Looking at omega events to compare perfomance at 1200 A vs. 1500 A in the solenoid.
    • Looks like there is a drop in performance due to reduction in background.
    • Started work on lambda to p pi- events, no conclusions yet.
    • In comparison of 1200/1500 A, see a 20% loss in Δp/p, but missing mass only worse by a few percent.


Paul gave a report:

  • He is in the middle of writing a kinematic fitter. Will incorporate 4-momentum conservation, time constraints, RF timing, vertex constraints
  • Using 7 variables in the covariance matrix: px, py, pz, t, x, y, and z.
  • Hopes to have results in two weeks.


Beni reports that he is having problems building a working copy of the GlueX software on an Ubuntu 64-bit system.

Review of Action Items and Repository Activity

  • Dmitry Romanov is scheduled to arrive back at JLab in early August.
  • We noted that Richard checked in a solution the the problem initially reported by David where hddm-xml was running out of buffer space.