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Meeting Details

  • Moderator: ssm
  • Protocol: peu
  • Attendees:
    • als
    • andy
    • nre
    • rvh
    • ssm
    • lgr
    • cds
    • peu
    • mek
    • fry
  • Start: 09:45
  • End:

Agenda

Analysis of Dynamic Ticks (andy)

  • Close to finishing
  • Implementation complete, now need to decide what tests should be conducted
  • May want to vary compiler strategy (rvh)
    • Try priority-based and state-based approach for Raspberry Pi and Atmega (unavailable for FPGA)
    • Test 3 (maximum RPM) with software approach may result in higher RPM than netlist?
  • Demonstrator features 2 interleaving disks to show that controls are precise enough to avoid collisions

Current Progress on Lustre and Related (lgr)

  • Compiling is tedious: SCADE → Lustre → SCCharts → Hostcode with SCADE → Lustre being a manual step so far
  • Can now transform SCADE → Lustre automatically
  • Automatically creates code structure for Lustre node
  • Automatically detects types and input / output variables
  • Substitute out local variables if they are not required
    • Remove SCADE variables introduced for each connection to reduce visual clutter
    • What if a connection has multiple targets? (rvh) → Will result in multiple occurences of the variable's equation.
    • Readability up for discussion
    • Include this as an option, but not the standard (rvh)
    • Needs more work, technical steps need more research and examples to adapt synthesis (ssm)
  • Resulting dataflow SCChart looks rather similar to SCADE model
  • SCADE will connect output and output's value in the next tick with a backloop and a PRE operator
    • SCCharts variant currently does not do that (see images)
    • May want to change that (rvh)
  • Merge this to master branch.


  • Initialization operator Lustre: Uses left side in first tick, then right side
  • This operator exists in KExpressions too, however stacked initializations did not work as expected before
    • Use separate regions for each operator
    • May be possible to optimize this to reduce the number of regions (als)
      • However, this introduces more complexity due to the streams being more complex in some cases
  • Lustre fby can be expressed using initialization and pre
    • Use optimized generation for stacked fby operators
      • May want to use manually saved values instead of using pre for some cases for performance reasons (als)
      • Some of these operators only make sense if variables are unavailable → should not invest too much into optimizing them (als)
  • More Lustre operators: At most one, nor, implies
  • Use these in a future release?
    • Introducing new operators always comes with some overhead (als, ssm)
    • More features never hurt (rvh)
    • Makes no sense to leave these out because they are not required, but leave init in
      • Need init to create dataflow initialization such as in ABRO (ssm)
    • Try to avoid using these operators wherever using sequential constructivity is more convenient (rvh)
      • May want to handle this in the fby transformation on SCCharts level
    • This remains open for future discussion
  • When operator now uses update instead of conditional

Various (nre)

  • Generating OSGI model for pragmatics and semantics now works
    • Can now view all bundles and their dependencies
    • Semantics will work as soon as a layout bug is fixed
  • When expanding nodes in OSGI model, the selected node will remain exactly where it is without zooming out or moving the diagram
  • Feedback from S&B: KIELER uses scrolling for zoom, clicking and dragging for panning
    • E.G. Browser: Scrolling pans up and down, shift + scrolling left and right, ctrl + scrolling zooms.
      • Browsers only have one dimension to move through, e.g. Google Maps uses the same as Kieler → Makes more sense (cds, rvh)
    • Use this as an alternative control mode?
      • May lead to even more requests and confusion (cds)
    • Perhaps use vertical and horizontal scrolling using Ctrl and Shift?
      • Must stay close to common software, e.g. Inkscape, Powerpoint, etc.
    • Conclusion: Leave default as it is

Orga (ssm)

  • KMeeting preliminarily now on Fridays
  • Semantics Lead formally passed on to als
  • Thanks to ssm!
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