Minutes of the Apr. 22 Offline Software Meeting

["Mark M. Ito" <marki@jlab.org>]

Find them at http://tinyurl.com/dxs2h7#Minutes and attached.

April 22, 2009 Software

Minutes

   Present: Beni, Simon, Mark I. (chair), Elliott, Elton, Sascha S., David
   L., Eugene

Announcements

   Mark will take over for Dave as the GlueX Software Coordinator. See the
   [26]announcement and [27]job description that Dave circulated for
   details.

Collaboration Meeting Agenda

   [29]Dave will give the 30-minute summary of the state of the offline at
   an abbreviated session at the upcoming collaboration meeting.

Kalman Filter Progress

   Simon presented an [31]updated version of the presentation he made at
   [32]last Monday's tracking meeting. Improvements include (from his
   second slide):
     * Improved agreement between geometries in MC and reconstruction for
       stereo straws
     * Handle cases where the true minimum doca would occur beyond the
       extent of the straw (still work in progress)
     * Fixed sign error and ordering problems in generation of reference
       trajectory for central tracks
     * Added energyloss straggling (very crude – assumes absorbers are
       thick enough that central limit theorem can be used)
     * Use vector algebra to find predicted measurement for stereo wires

   The last item accounted for most of the improvement between last Monday
   and today.

   One plot that he showed showing the residuals as a function of polar
   angle for ideal tracks (no MCS, no dE/dx, no position smearing) when
   the Simon-authored swimming routine was used in reconstruction (slide
   3) generated a lot of discussion. We agreed that the lack of
   delta-function residual distributions was due to using different
   swimming algorithms in event generation vs. reconstruction. Some
   thought that this could be sorted out later; for now using the same
   algorithm in both places was enough to make progress on other fronts.
   Others thought that this might indicate something more fundamental that
   needs to be addressed sooner to eliminate that possibility. At any rate
   this made it to the list generated in the brainstorming session (see
   below).

   From Simon's summary:

   Transverse momentum resolution for 1 GeV pions improved by a factor of
   4 around theta=90° compared to March'09, but dip angle resolution is
   still poor for some angular regions...
     * Problems in p_T and phi start to occur towards CDC-FDC transition
       region and for very backward angles
     * Sensitivity to quality of initial guess for track parameters


Software Brainstorming

   We generated a list of topics that were on peoples minds. Numbered only
   for reference (i. e., unprioritized), they were:
    1. Tracking
         1. transition region
         2. Kalman
         3. swimming algorithm
         4. standard definitions
               o finding
               o fitting
         5. multi-track events
         6. FDC geometry update: Simon
         7. local Lorentz correction for FDC hits
         8. CDC geometry update: Beni
         9. Alternate tracking philosophies
        10. tracking efficiency over-all: single tracks, multi-tracks
    2. Simulation
         1. parametric MC
               o update/expand resolution tables
    3. Miscellaneous
         1. new release
         2. calibration database: firewall penetration
         3. milestone review
         4. reconstruction->PWA interface

   Also note that this reflects the focus of the people in the room.

   Clearly tracking is our highest priority, summarized by the last item
   in the tracking section tracking, i. e., efficiency over-all: single
   tracks, multi-tracks.
     * Beni agreed to look at finalizing the FDC geometry in the MC.
     * Simon agreed to update the FDC geometry.

   Retrieved from http://www.jlab.org/Hall-D/software/wiki/index.php/April_22%2C_2009_Software

References

  26. http://www.jlab.org/ccc/mail_archives/HALLD/halld-offline/msg00839.html
  27. http://dustbunny.physics.indiana.edu/mailman/private/gluex/2009-April/002627.html
  29. http://www.jlab.org/ccc/mail_archives/HALLD/halld-offline/msg00837.html
  31. http://www.jlab.org/~staylor/kalman220409.pdf
  32. http://www.jlab.org/Hall-D/software/wiki/index.php/April_20%2C_2009_Tracking_CDC/FDC