GQLink: outline of Fermilab presentation

  1. Quantized state system (QSS) methods [~14m]
    1. Introduction
      • Definition of discrete event-based integration methods.
      • High-level definition of QSS: quantized variables, integration steps, sample plots.
    2. QSS features
      • Advantages of QSS methods: lightweight handling of discontinuities.
      • Brief comparison against traditional time-stepped integration methods.
    3. Standalone tool: QSS Solver
      • One slide to quickly introduce this tool (do mention availability of other integration methods).
      • Summarize Nico's results (i.e., the Solver scaled better with increasing number of crossing planes). Include a comment that emphasizes on a good case, e.g. "we reached up to x% of speedup for a case with N planes and track length of T".
  2. GQLink: an implementation of QSS3 within Geant4 [~13m]
    1. Technical aspects
      • High-level description of how GQLink/QSS was wired into Geant4 for invoking QSS3.
      • Sequence diagram
    2. CMS application analysis
      1. Data validation
        • Histograms of particle steps (e-, pi-, pi+?) after 10^4 events (particle gun).
        • Same as above but using 50 events from physics data?
      2. Benchmarking
        • Discuss runtime of GQLink against Geant4 (~27% slower). Third order QSS vs. RK 4/5.
    3. Alternative scenarios
      • Briefly mention N02 helicoidal movement with crossing planes (asking G4 for the field and with no direction changes).
      • Runtime plot?
  3. Conclusions and future work [~3m]
    • Discuss preliminary GQLink performance on the realistic CMS experiment app (Message: "We have a prototype, and need to fine tune it to provide at least the same performance as G4").
    • Discuss potential benefits on certain alternative scenarios (combinations of few stepwise direction changes; several geometry crossings).
    • Third-order QSS vs. fourth/fifth order RK (QSS4 is still experimental but will eventually become available and, having GQLink in the middle, we won't need to change anything but a configuration flag).
    • Abstract viewpoint: GQLink opens new possibilities by connecting Geant4 with external steppers (not limited to the QSS family).
    • Future work: usage of QSS polynomials to detect boundary crossings.