[FRIAM] on selection pressure

Wed Jan 2 11:48:51 EST 2019

Hi Stephen,

Thanks for the paper.  I have some colleagues that study deceptive energy landscapes but it is a different literature.

[I do like trying to figure out “How the hell did that work?!” more than a workman-like construction project.  Maybe up to a point when the experiments and reverse engineering just get to be too hard (biology).]

Marcus

From: Friam <friam-bounces at redfish.com> on behalf of Stephen Guerin <stephen.guerin at simtable.com>
Reply-To: The Friday Morning Applied Complexity Coffee Group <friam at redfish.com>
Date: Wednesday, January 2, 2019 at 9:36 AM
To: The Friday Morning Applied Complexity Coffee Group <friam at redfish.com>
Subject: Re: [FRIAM] on selection pressure

Very cool, Marcus!

Did you interact with Ken Stanley (https://scholar.google.se/citations?user=6Q6oO1MAAAAJ&hl=en&oi=ao) when he was at SFI a couple years back? Ken's research would support your observations on the importance on the pressure to maintain novelty/diversity in evolutionary algorithms vs the focus on the objective function.

In particular this paper:
  https://www.mitpressjournals.org/doi/pdfplus/10.1162/EVCO_a_00025

Also, Ken's homepage:
  http://www.cs.ucf.edu/~kstanley/ with more popular book links and Santa Fe Radio Cafe Interviews.

BTW, in the late 90's I was working a bit on evolving weights and topologies of neural networks and was very inspired by Ken's advisor, Risto Miikkulainen, and his team at UT Austin:
  https://www.cs.utexas.edu/users/risto/
  http://nn.cs.utexas.edu/pub-list.php

_______________________________________________________________________
Stephen.Guerin at Simtable.com<mailto:stephen.guerin at simtable.com>
CEO, Simtable  http://www.simtable.com<http://www.simtable.com/>
1600 Lena St #D1, Santa Fe, NM 87505
office: (505)995-0206 mobile: (505)577-5828
twitter: @simtable

On Wed, Jan 2, 2019 at 9:11 AM Marcus Daniels <marcus at snoutfarm.com<mailto:marcus at snoutfarm.com>> wrote:
Some memory, and the ongoing recombination and optimization of less fit (high energy) individuals which tend to create other less fit individuals.
In this optimization system there are numerous methods that are used to create fit individuals, but the ones that create the very best individuals do not arise from recombination + selection pressure.   Mixing two distinct (large Hamming distance) globally constraint-satisfying solutions tends to create a non-constraint satisfying solutions.  It is only once the two parents are very similar (e.g. same species) that such a recombination will even work, but by then it doesn't do all that much.

Computationally, it easier to try more approaches and maintain a large population than it is accelerate the algorithms that are most effective.  (For the former, just add more cores.)

On 1/2/19, 8:57 AM, "Friam on behalf of ∄ uǝʃƃ" <friam-bounces at redfish.com<mailto:friam-bounces at redfish.com> on behalf of gepropella at gmail.com<mailto:gepropella at gmail.com>> wrote:

    Are there computational (or otherwise not shown) costs to the members that continue in the free case but are pruned in the selection case?

    On 1/2/19 7:44 AM, Marcus Daniels wrote:
    > Here are a couple of plots from a large constrained optimization problem I've been running.
    > In the first case, I apply selection pressure:  If a solution is not in the top 200 performers, it dies.
    > In the second case, the population can continue to grow without concern for its performance.
    > This is a 5900-dimensional pseudo-boolean problem and the best-known solution is around 2.61e+08.   Note the low end of the y axis is not close to this.   In both cases, aggressive efforts are made to diversify the population and in both cases every shown solution is unique (even though their energies can collide).
    >
    > In this case, I would argue that selection pressure has accomplished nothing -- conservatism doesn't work if the goal is to create the most fit individuals.  The mean moves, if you care about that.   But the very best solutions are nearly the same, and neither have come close to the optimal.

    --
    ∄ uǝʃƃ

    ============================================================
    FRIAM Applied Complexity Group listserv
    Meets Fridays 9a-11:30 at cafe at St. John's College
    to unsubscribe http://redfish.com/mailman/listinfo/friam_redfish.com
    archives back to 2003: http://friam.471366.n2.nabble.com/
    FRIAM-COMIC http://friam-comic.blogspot.com/ by Dr. Strangelove

============================================================
FRIAM Applied Complexity Group listserv
Meets Fridays 9a-11:30 at cafe at St. John's College
to unsubscribe http://redfish.com/mailman/listinfo/friam_redfish.com
archives back to 2003: http://friam.471366.n2.nabble.com/
FRIAM-COMIC http://friam-comic.blogspot.com/ by Dr. Strangelove
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://redfish.com/pipermail/friam_redfish.com/attachments/20190102/d5abcf19/attachment.html>