An Introduction to Genetic Algorithms - Boente

3.
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4.
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the female child in the next generation's female population. If the female decides not to mate,
put the male back in the male population and, keeping the same female, choose a male again
with probability proportional to fitness. Continue in this way until the new male and female
populations are complete. Then go to step c with the new populations.
What is the behavior of this GA? Can you explain the behavior? Experiment with different
female preference functions to see how they affect the GA's behavior.
Take one of the problems described in the computer exercises of chapter 1 or chapter 2 (e.g., evolving
strategies to solve the Prisoner's Dilemma) and compare the performance of three different algorithms
on that problem:
a.
The standard GA.
b.
c.
Chapter 3: Genetic Algorithms in Scientific Models
The following Baldwinian modification: To evaluate the fitness of an individual, take the
individual as a starting point and perform steepestascent hill climbing until a local optimum is
reached (i.e., no single bit−flip yields an increase in fitness). The fitness of the original
individual is the value of the local optimum. However, when forming offspring, the genetic
material of the original individual is used rather than the improvements "learned" by
steepest−ascent hill climbing.
The following Lamarckian modification: Evaluate fitness in the same way as in (b), but now
with the offspring formed by the improved individuals found by steepest−ascent hill climbing
(i.e., offspring inherit their parents' "acquired" traits).
How do these three variations compare in performance, in the quality of solutions found, and
in the time it takes to find them?
The Echo system (Jones and Forrest, 1993) is available from the Santa Fe Institute at
www.santafe.edu/projects/echo/echo.html. Once Echo is up and running, do some simple experiments
of your own devising. These can include, for example, experiments similar to the species−diversity
experiments described in this chapter, or experiments measuring "evolutionary activity" (à la Bedau
and Packard 1992).
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