[Halld-offline] Offline Software Meeting Minutes, February 1, 2017

Sun Feb 5 18:39:53 EST 2017

Computers,

Please find the minutes below and at 
https://halldweb.jlab.org/wiki/index.php/GlueX_Offline_Meeting,_February_1,_2017#Minutes 
.

   -- Mark

_______________________

    Minutes

Present:

  * *CMU*: Naomi Jarvis, Will McGinley
  * *FIU*: Mahmoud Kamel
  * *JLab*: Thomas Britton, Mark Ito (chair), Peter Pauli, Nathan
    Sparks, Simon Taylor, Beni Zihlmann
  * *MIT*: Maria Patsyuk
  * *Regina*: Tegan Beattie
  * *UConn*: Richard Jones
  * *W&M*: Justin Stevens

There is arecording of this meeting <https://bluejeans.com/s/LIDGf/>on 
the BlueJeans site.

      Announcements

  * *New releases of hdds and sim-recon: hdds-3.9, sim-recon-2.11.0
    <https://mailman.jlab.org/pipermail/halld-offline/2017-January/002601.html>*.
    The release came out on January 24. See the link for the announcement.
  * *New SciComp Web Portal
    <https://mailman.jlab.org/pipermail/jlab-scicomp-briefs/2017q1/000133.html>*.
    Thenew site <http://scicompnew.jlab.org/>is in beta release now.
    SciComp is soliciting feedback on the page. There is a "Suggestion"
    button at the top of the page for your convenience in doing so.

      Review of minutes from the last meeting

We went overthe minutes from the meeting on January 18 
<https://halldweb.jlab.org/wiki/index.php/GlueX_Offline_Meeting,_December_21,_2016#Minutes>.

  * *Backups of the RCDB database in SQLite*. Mark reminded us that we
    cannot use an SQLite database if it is sitting on a Lustre file
    server. It must be copied to a non-Lustre disk first. Unfortunately,
    the backup location, /cache/halld/home/gluex/rcdb_sqlite/, on Lustre
    so that it will get written to tape automatically. (The directory is
    part of the write-through cache.)
  * *Lustre Recovery*is complete. They were able to restore 4 of the 5
    OSTs that had been corrupted. Files that remain that cannot be
    accessed will not be coming back.

      A wrapper for signal MC generation

Thomas has written a wrapper for generation of signal Monte Carlo data. 
The script does event generation (genr8), detector simulation (hdgeant), 
and signal smearing (mcsmear) with the input of a minimal set of 
parameters. Several people have private approaches to this problem, but 
this is an attempt to consolidate approaches. Other generators will be 
added in the future.

For now the script can be found in the sim-recon git repository, in 
src/programs/Utilities/MCwrapper. We discussed whether we should change 
it to the hd_utilities repository; the matter will be addressed offline.

      Collaboration Meeting Agenda

We looked at the current state of the offline section of 
thecollaboration meeting agenda 
<https://halldweb.jlab.org/wiki/index.php/GlueX-Collaboration-Feb-2017>:

        Saturday February 18, 2017

  * 9:00 Session IIb (100) --- Analysis/Offline/Calibration -
    (Organizer: Sean Dobbs) - Chair: -
      o 9:00 (25) --- Offline Software Status -- Mark Ito
      o 9:20 (25) --- Calibration Status -- Sean Dobbs
      o 9:40 (20) --- Offline Data Processing --- Alexander Austregesilo
      o 10:00 (20) --- HDGeant4 Update --- Richard Jones
      o 10:20 (20) ---

If you have suggestions, contact Mark.

      HDGeant4 Status

Richard sent outan email 
<https://mailman.jlab.org/pipermail/halld-offline/2017-January/002610.html>yesterday 
summarizing progress on HDGeant4. He notes in closing that "HDGeant4 is 
now mature enough to pass into production."

At the meeting he told us that development is done; all essential 
features have been implemented.

He showed details of the comparisons he has used to both expose issues 
with HDGeant (HDG3) and drive development of HDGeant4 (HDG4) that rely 
on the MCTrajectories that give verbose, step-by-step information about 
particle propagation. He turned off production of secondary particles to 
facilitate comparison.

The build of HDG4 has fixes to the vanilla Geant4 distribution that 
fixes bugs. He urged us to take advantage of those fixes (as happens 
naturally in the build).

He compared the total track length of particles produced in three 
particles: photons, neutrons, and others. The numbers are comparable in 
the HDG3/HDG4 comparison, but there is about twice as much total track 
length in HDG4, due mainly to neutrons being propagated down to lower 
energy.

The total number of particles was shown in three categories: photons, 
electrons, and others. There are only about 30% more particles in HDG4, 
but the proportion of photons increases from 25% for HDG3 to 50% for 
HDG4 due to lower cut-offs in the photon simulation. Conversely, 
electrons go from 50% to 20%.

After a lot of work studying where time was being spent in HDG4, Richard 
has improved performance to the point where HDG4 is now a factor of 4 
slower, per event per thread, than HDG3. Very roughly speaking, a factor 
of 2 comes from lower energy thresholds for tracking and the other 
factor of 2 is just code speed, i. e., the object-oriented C++ code 
takes twice as long to do the same thing as FORTRAN.

We could increase the throughput by raising thresholds, but at most that 
would give is a factor of two, with possible reduction in the fidelity 
of the simulation. He recommends that we proceed with the standard 
thresholds, at least to start, given the uncertainty in costs vs. 
benefits from ignoring physics at low energies.

Richard is interested in receiving problem reports asissues on GitHub 
<https://github.com/rjones30/HDGeant4/issues>. He explained his taxonomy 
of such reports, listed in order of Richard-will-look-at-it priority.

 1. *Bugs*. Things that are obvious problems, e. g. seg faults, things
    that halt progress, things that are non-physical.
 2. *Artifacts*. Observation of behavior that "does not make sense".
    These could be bugs, but they also might be features.
 3. *Anomalies*. Reports of behavior of HDG4 that is not exactly the
    same as with HDG3.

Richard requires problem reports that include a recipe for reproducing 
the problem. He has provided a tool, hddm-root, that will make spectra 
from the raw HDDM output of HDG4 (and HDG3). Spectra produced in this 
way get around the problem of having identical collections of versions 
of the software stack. In addition, discussion on the gluex-software 
email list can be used to refine improve the utility of the report.

The DIRC simulation will include optical photons. Work here is not done 
but is not the top priority at this time.

For details, seethe recording <https://bluejeans.com/s/LIDGf/>. 
Richard's presentation starts at the 36:00 mark.

      Launches

Paul have the report. Since the last meeting Alex Austregesilo announced 
completion ofMonitoring Launch, 2016-10, ver03 
<https://mailman.jlab.org/pipermail/halld-offline/2017-January/002602.html>andAnalysis 
Launch, 2016-02, ver05 
<https://mailman.jlab.org/pipermail/halld-offline/2017-January/002603.html>. 
The analysis launch took a long time due to a small number of events in 
multi-photon channels that took forever to analyze. In these channels 
the cut on the number of neutral particles had to be tightened from 20 
to 14.

      Calibration Efficiency

Beni has noticed that for the Fall 2016 data, more events are needed to 
get good timing calibrations for the TOF. We discussed several possible 
reasons for this but did not come to a conclusion about the cause.

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