[Halld-offline] Minutes, GlueX Offline Meeting, March 23, 2011

[Mark M. Ito]

Find the minutes at 
http://www.jlab.org/Hall-D/software/wiki/index.php/GlueX_Offline_Meeting%2C_March_23%2C_2011#Minutes 
and below as text.

   ==

GlueX Offline Meeting, March 23, 2011
Minutes

    Present:
      * CMU: Will Levine, Curtis Meyer
      * IU: , Mihajlo Kornicer, Kei Moriya, Matt Shepherd
      * JLab: Mark Ito (chair), David Lawrence, Simon Taylor, Elliott Wolin
      * UR: Zisis Papandreou, Andrei Semenov

    (not sure I got everyone...let me know if your name is missing)

Announcements

      * Elliott announced that there are two CNU students starting on the
        Java-based event display.
      * Matt is developing a new cluster finder for the BCAL. It is work in
        progress at present.


Review of minutes from the last meeting

    We went over the [35]minutes from the March 9 meeting. Zisis
    recommended that in the re-organization of the Offline Software wiki
    page, the instructions on how to get started should be easily located
    and their contents reviewed and updated. Newcomers should know what
    they should be looking at and the material should be accurate.

SIMD speed enhancement

    David showed a [37]histogram of the event analysis rate for several
    intervals during a reconstruction run. He made the plot for code with
    SIMD instructions enabled and without. He repeated the exercise for
    other combinations of number of cores (on the machine) and number of
    threads with consistent results. He concludes that the SIMD
    instructions are giving us about 5% to 10% improvement in execution
    speed.

    We agreed that given this situation, leaving the default state of the
    code with SIMD-off is sensible.

Floating point entropy

    Recently Richard diagnosed a [39]problem that was causing segmentation
    faults in our reconstruction code. Richard made a [40]proposal for a
    review of our code looking for problematic instances of comparisons of
    floating point numbers. We decided that we needed Richard to lead this
    discussion and tabled the issue for now.

Make system, includes, in JANA and sim-recon

    Matt re-capped [42]his proposal that the make system use only include
    files that exist in the source distribution tree and not rely on files
    from an "installed" location. That way a recent check-out will not have
    to have any "make install" prerequisites before "make".

    We had some discussion. Mark thought that the proposal made sense.
    David pointed out that if one does from-the-top make, then all the
    necessary installs will be performed. He also pointed out that the
    sim-recon code has a slightly different usage pattern, as it is usually
    the end product build, not really a package to be used by other
    packages, therefore the "install" could or should be different than
    from other cases.

    We did not come to a conclusion. More discussion is needed.

BCAL studies and build issues

    At the [44]March 10 BCAL Readout meeting Andrei and Irina reported
    difficulty using our offline software and it was suggested that the
    issues be discussed at this meeting. Since then the problems have been
    resolved, but there were a couple of lessons learned:
      * Our "getting started" documentation needs to be updated (see item
        above on wiki page re-organization).
      * Mark's build scripts need better documentation.


FFREAD modifications

    We briefly discussed issues surrounding the use of FFREAD cards in our
    GEANT3-based simulation, in particular an issue with decimal points and
    one on the number of characters in a card identifier. See the thread
    rooted on [46]this message in the email archive. We decided for now
    there was no action to be taken; it is best that we just learn to use
    the code as it is.

New Action Items

     1. Decide on Matt's include-related proposal for the make system(s).
     2. Our "getting started" documentation needs to be updated.
     3. Mark's build scripts need better documentation.

    Retrieved from
    
"http://www.jlab.org/Hall-D/software/wiki/index.php/GlueX_Offline_Meeting%2C_March_23%2C_2011"

References

   35. 
http://www.jlab.org/Hall-D/software/wiki/index.php/GlueX_Offline_Meeting%2C_March_9%2C_2011#Minutes
   37. 
http://www.jlab.org/Hall-D/software/wiki/images/1/14/20110318_simd_rates.pdf
   39. 
http://www.jlab.org/Hall-D/software/wiki/index.php/Diagnosing_segmentation_faults_in_reconstruction_software
   40. 
https://mailman.jlab.org/pipermail/halld-offline/2011-March/000591.html
   42. 
https://mailman.jlab.org/pipermail/halld-offline/2011-March/000568.html
   44. 
http://www.jlab.org/Hall-D/software/wiki/index.php/Mar_10%2C_2011_Readout
   46. 
https://mailman.jlab.org/pipermail/halld-offline/2011-March/000601.html