[Halld-offline] Offline Software Meeting Minutes, August 20, 2014

Mark M. Ito marki at jlab.org
Fri Aug 22 14:35:46 EDT 2014


Find the minutes below and at 

   -- Mark

GlueX Offline Meeting, August 20, 2014

      * CMU: Will Levine, Paul Mattione, Curtis Meyer
      * FSU: Aristeidis Tsaris
      * IU: Ryan Mitchell, Matt Shepherd
      * JLab: Alex Barnes, Mark Ito (chair), David Lawrence, Nathan Sparks,
        Mike Staib, Beni Zihlmann
      * MIT: Justin Stevens
      * NU: Sean Dobbs
      * UConn: Richard Jones


      * David has released [33]JANA 0.7.2. Among other features it includes
        verification of MD5 checksums for resource files.

Review of Minutes from August 6

    We looked at the [34]minutes.

    Mark "fixed" the broken trunk problem, induced by a change in the table
    definitions for tagger counters in the CCDB, by simply removing the
    "exit" in the code when an error is detected in hitTag.c. David
    reported that Simon Taylor reported that this induced an effective
    memory leak in the code where the unsuccessful attempt to fetch the
    constants was repeated for each event, using a small amount of memory
    each time. Richard thought that rather than trying to fix this, we
    should wait for the new version of hitTag that actually requires the
    aforementioned CCDB table change. This will come when the development
    branch (discussed below) is checked onto the trunk.

Tagger Simulation Update

    Richard and Paul have been working on a branch of sim-recon, namely
    sim-recon-rj-pm, to [35]add realism to the global timing scheme of the

HDDM Calls: Conversion to C++ API

    All invocations of the HDDM API have been upgraded to use the C++
    version rather than the old C version. This change comes in many places
    in the sim-recon tree. The exception is the GEANT-3-based code, in
    particular the current HDGeant; that conversion will come with the
    conversion to Geant4.

HDDM Integrity Checks

    The HDDM library now supports "integrity checks" where a cyclic
    redundancy check (CRC) code is computed event-by-event and can be
    written with the event. Downstream programs can check that incoming
    data has not been corrupted.

HDDM_s Changes

    The template for simulation output has been changed to rationalize the
    arrangement of data in two areas: (1) the mix of truth and hit
    information and (2) the detector component hierarchy. A generic example
    of the latter is using enclosing elements to indicate "layer" rather
    than encoding "layer" as an attribute of each hit. Note that changes of
    this nature are indicated in the HDDM_s version in the template
    contained in every data file.

Merging Strategy

    As he has been making these changes, Richard has been periodically
    merging changes made to the trunk onto his branch. In this way
    integration testing can proceed on the branch before merge of the
    branch back onto the trunk.

Tagger Analysis

    CCDB tagger tables have been rationalized and new C++ classes
    introduced in sim-recon to accommodate the new scheme. The start
    counter was used as a model for the low-level hit classes in the DAQ
    plug-in. There were some modifications needed to HDGeant (GEANT3) code
    to write the new classes.

Analysis Library Changes

    Paul will need to change the analysis library to deal with the
    ambiguity of the "correct" tagger hit. For now he will use the factory
    tag for the tagger to get the true tagger hit. That makes things more
    or less as things were before. Once the merge onto the trunk is done,
    he will implement the necessary changes.

    Paul and Will have found a problem on the branch where TDC hits from
    the upstream BCAL are missing. This will have to be fixed by Richard
    before the merge-back is done.


    Beni asked if the new library will support named pipes connecting HDDM
    producing and consuming programs, e. g. HDGeant to mcsmear. Richard
    thought that this should have been working all along, but Beni has had
    trouble getting it to go. We decided to take further discussion


    Gxtwist is a stand-alone simulation of the tagger hall. Richard has
    updated the geometry based on the latest drawings. This has been
    checked in on the trunk. He has also added reality to the radiator with
    separate positions for the diamond and the amorphous radiators.

Re-Creating Tracks

    There was a [36]discussion on the email list about re-creating tracks
    with mass hypotheses that are not present in the set coming from track
    reconstruction. This can be very time-consuming. In these cases usually
    the fit failed when using the mass assumption in question. Simon is
    working on solving this problem in tracking so a full set of mass
    hypotheses are available in the REST file. See the email discussion for

Commissioning Geometry Simulation

    An effort has started by Sean and Simon to simulate the detector with
    the commissioning geometry. A branch of HDDS has been made for this
    work and Simon has started putting in the commissioning target.

Analysis of Six Final States Using Data Challenge 2 MC

    Ryan has looked at the following reactions generated in Data 
Challenge 2:
     1. \gamma p \rightarrow \pi^+\pi^- p
     2. \gamma p \rightarrow \pi^+\pi^-\pi^0 p
     3. \gamma p \rightarrow K^+K^- p
     4. \gamma p \rightarrow \pi^+\pi^-\pi^+\pi^- p
     5. \gamma p \rightarrow \pi^+\pi^-\pi^+\pi^-\pi^0 p
     6. \gamma p \rightarrow \pi^+\pi^-\pi^+\pi^-\pi^+\pi^- p

    The data set is comprised of 10 M events at 1×10^7 photon rate, about
    1% of the events generated for DC2.

    He is using analysis code he developed for use at CLEO and BES. (As a
    check, Matt has been using Paul's analysis library in a parallel
    analysis to compare and contrast results. It was in this context that
    he discovered the track re-creation time sink mentioned above.)

    Please see [37]his slides for the plots.

    The mass distributions for the multi-pion systems in many reactions
    peaks much higher than people expected.

Data Challenge 3

    Mark has succeeded in creating EVIO format simulation data. Sean told
    us that reconstruction of this data should not be a problem.

Action Items

      * Fix BCAL bug on tagger reconstruction branch and merge onto trunk.
        (Richard and Paul)
      * Ask Simon about track re-creation. (Mark)
      * Develop the simulation for the commissioning geometry. (Sean,
      * Will will send problematic BCAL timing events to Richard. (Will)

   37. https://halldweb1.jlab.org/talks/2014-3Q/SixFinalStates.pdf

Mark M. Ito, Jefferson Lab, marki at jlab.org, (757)269-5295

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