[FRIAM] on selection pressure

[Marcus Daniels]

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 on behalf of 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