Definition of discrete event-based integration methods.
High-level definition of QSS: quantized variables, integration steps, sample plots.
QSS features
Advantages of QSS methods: lightweight handling of discontinuities.
Brief comparison against traditional time-stepped integration methods.
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".
GQLink: an implementation of QSS3 within Geant4 [~13m]
Technical aspects
High-level description of how GQLink/QSS was wired into Geant4 for invoking QSS3.
Sequence diagram
CMS application analysis
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?
Benchmarking
Discuss runtime of GQLink against Geant4 (~27% slower). Third order QSS vs. RK 4/5.
Alternative scenarios
Briefly mention N02 helicoidal movement with crossing planes (asking G4 for the field and with no direction changes).
Runtime plot?
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.