Monthly Archives: July 2014

22 July 2014

Present

Lee, Thom, Bill, Karthik, Tim, Wren, Omri (scribe)

Administrative

New CS hire for grant administration stuff: Lisa Karlin (things that used to go to Jean should go to Lisa)

Dartmouth trip next Monday, involves

  • A PhD defense that has to do with evolution and networks, public defense 10-11AM
  • A possible meeting with Jason Moore’s research group (studying GP and genetics, among other things), sometime between 1-3PM
  • Lee is giving a seminar from 3-4PM (“Expressive Program Evolution”)

Currently this week, Lee is participating in a(n awesome) workshop on open-ended evolutionary computation with Wolfgang Banzhaf and Susan Stepny (in Newfoundland, via Skype)

Plush woes

Plush programs are getting really big. Why? We don’t know, and it’s quite a problem.

Lexicase paper

Due August 6th

Thom will be back from Florida August 1s with revisions

Lee will have time to review and write a letter

Semantic distance

Karthik queries: how do you measure semantic distance in GP?

Maybe base it off of constraints?

Hard problem!

Next week

Meeting at regular time and place, i.e. ASH Conference Room 9:15-10:30AM (Tues July 29th)

People planning to go to Dartmouth

Get to Lee’s house at 7:30 on Monday (July 28)!

Lab meeting notes 08 July 2014

Present : Lee, Tom, Bill, Karthik(Scribe), Tim

Administrative stuff : GECCO next week, Frode’s presentation got moved to the first session/first talk.

Clojush 2.0 : 
Clojush 2.0 nearing release – Mixed results so far on different problems in terms of success rate on different problems, but this is not the current priority – the idea’s that going to a linear genome allows for greater capabilities that can be subsequently explored.
Clojush 2.0 is *NOT* backwards compatible – the “Plush” genome is what’s manipulated to eventually generate a Push program.
Close-paren probabilities come from a binomial distribution. Modify/tweak this for it to get slightly better before full release ?
– Availability of Hill Climbing genetic operators on Plush.
– Selection *mid-generation* ? + Not use reversion/ use it “reasonably” ?
– Experiments on potential reversion.
– Lein deploy : long term thing to do, but not a priority.

Tom’s GECCO talk practice :- 
– The overall idea of using GP for “traditional” programming problems.
– Some details on Lexicase selection.
– Minor details on Push, since code is evolved in Push.
– The ULTRA genetic operator.
– The idea of achieving *perfect* solutions, at least with respect to both the training data and the unseen test data.

To-Do’s :

– Send Lee details on plans for next week(s), since we won’t be meeting next week thanks to GECCO.

– Talk about the meeting with Jason Moore in the next meeting.

1 July 2014

Administrative

  • Present: Lee, Tom (scribe), Tim, Karthik (remote), Bill (remote)
  • Tom will practice GECCO talk next week
  • Frode should send us GECCO slides shortly

Plush genomes -> Push programs

  • Do we want any Push program to be able to be represented by a Plush genome?
    • Lee: Yes!
    • Tom: Maybe?
  • To do so, we have new instructions:
    • meta_open – opens new paren
    • meta_splice_backward – deleted previous paren pair

Hill-climbing vs. Genetic Operators

  • e.g. simplification, epigenetics, etc.
  • Is it useful to test and revert (using a fitness evaluation), or is just making the change and letting selection work it out just as good?
  • Maybe Bill or Tom should experiment with this — EHC vs. using epigenetic genetic operators with more generations to make up for EHC’s extra evaluations.
  • Simplest is to never do hill climbing, just have genetic operators.
  • Decision: Implement a wrapper argument (like :make-reverting) that can be used in genetic operator pipelines that cases the next operator to be reverted if not better than its input program.

Issue of what to do with child programs that exceed size limits

Decision: implement argument with these options:

  • return clone of one parent (default, as previously)
  • return empty program
  • return random program
  • return one parent with some part(s) deleted