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non-homogenizing dynamics. Furthermore, mutation is the only genetic operator
capable of reaching the performance peak and, for each system, this peak
can be found. For this particular problem, the performance peak is shown in
Figure 12.5. In this case, maximum performance is reached around a mutation
rate
p
m
= 0.05. Therefore, this value will be used throughout this study. The
healthy and strong non-homogenizing dynamics of Figure 12.6 was obtained
for a successful run of the experiment summarized in the first column of
Table 12.2.
100
90
80
70
60
50
40
30
20
10
0
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
Mutation rate
Figure 12.5.
Determining the performance peak using mutation alone. The success
rate was evaluated over 100 identical runs.
As for recombination, this operator is the less powerful of all GEP opera-
tors and populations undergoing recombination alone display homogenizing
dynamics. Furthermore, we have also seen in the previous section that the
three kinds of GEP recombination (two-point, one-point, and gene recombi-
nation) perform better at maximum rates of 1.0, and that two-point recombi-
nation is the most powerful of the three recombinational operators whereas
gene recombination is the less powerful. However, for this particular prob-
lem and the particular settings chosen for this analysis, when used sepa-
rately, the three kinds of recombination perform so poorly that the three
recombinational operators were combined together so that the performance
