Week 13

Final Assignment / Parallel Composition in Golang

Final Assignment

  • Due: end of classes
    • Tue, May 5, 11:59pm
    • Marc's office
  • Logistics
    • handout: paper copy of full assignment and problem descriptions
    • submit electronically via submit377 script: 
      $ submit377 final my-final
  • The S'mores Problem
    • background clip from The Sandlot (S'mores scene): https://youtu.be/XlddDZkkxCc
    • implement using Ruby/Rinda where processes coordinate using tuples as semaphores to make S'mores
  • The Water Molecule Problem
    • chem background: Water molecule made up of two hydrogen atoms and one oxygen atom
    • implement using Golang, represent atoms as goroutines that must coordinate to form a water molecule (also a goroutine)

Parallel Composition in Golang

  • this is ongoing research I've been doing with my RAs going back to before the pandemic
  • recall Legoland as implemented in Peter Welch's occam slides: PDF
  • implementing Legoland in golang presents a challenge: no PAR!
    • demo without PAR
    • demo with a PAR
      • and some lambdas…
  • demo of sort pump with PAR and Replicated PAR

Simulating Models of Concurrency

  • Discussion: modeling one model of concurrency with another
    • shared memory (critical sections, etc.)
      • we've seen implementing semaphores with monitors/condition variables (Java)
      • can we model condition variables with semaphores?
    • Golang: channels (message passing)
      • motto: Don't communicate by sharing memory, share memory by communicating.
      • simulate memory accesses with a goroutine?
    • Ruby/Rinda: Linda and Tuple Space
      • tuples are semaphores!
      • immutable so no race conditions / critical sections
      • similar perils to using semaphores, but offer more possibilities
    • Simulate Linda/TS with another model?
      • with combination of dictionaries, nested dictionaries, hashmaps
      • shared memory with semaphores
      • goroutines to protect access
    • other ideas?
  • We don't always get to choose our language/library/stack