14 August 2013

14 August 2013


Lee, Tom, Kyle, Jake, Dave (scribe) , Dan


Some progress in Brevis. Moving along, but some trouble with scroll bars. A little faster, but looks about the same.

ULTRA speedup

Lee noticed that it was stalling for a long time during genetic operators. Lots of lists used. Tom pushed an updated version that’s about 2X as fast.

Lexicase Elite Group Selection

  • IF any two cases have same elites, they are part of the same elite group.
  • Didn’t really work better, but pushed to master.
  • Tried removing any groups that pick out a subset of another elite group.
  • Sometimes getting 0 elite groups- might be a bug (fixed after meeting)


By Daniel Now at http://sites.hampshire.edu/ci-lab/ Wordpress page – possible to edit, rewind, etc. To replace wiki

Mult. Weight Updates Paper

  • they made a lot of assumptions (infinite pop, random mating, etc.)
  • in finite pop you lose and gain haplotypes over time- not a good assumption
  • No geography
  • Mixability is interesting idea, though – the evolve solutions robust to evolutionary operators
  • What is the relationship between GP and MWU?
  • What about ULTRA without mutation? without crossover?
  • Can we try payoff matrix? (Kyle already tried something similar)


Les Valiant’s problem – 100 variables, 50 are relevant – are sum of bits for 50 even or odd? (Original 1000, 500) Big Question: Are you allowed to choose the test cases? May be trivial if you are allowed to choose, but paper does not specify selection method


(Calc problem: A fitness case is a sequence of button presses, output is what is displayed on screen: number or error). Each button tags some code. Tried lexicase selection and improvements some ideas:

  • more tagging instructions
  • don’t re-tag: later tag changes become a no-op
  • binary branching for bushier trees
  • re-think tests cases (separate error-flag from numerical; char based, not numerical error)
  • Binary fitness?? (Wrong or right in each case — is it too little information)

Anyone who has any ideas is welcome to try them

Next meeting: 8/26 or 8/27 (28-30 not viable)

To do:

Read Dave’s Paper Brevis demo (Daniel): Bring site up to date and make it the new site redirect from Hampedia (Kyle): Ask Valiant if we understand description correctly

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