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In-Depth Information
The expression of the best individual of this generation (chromosome 19)
and the corresponding mathematical expression are shown in Figure 5.9.
Note how simplistic this individual is, not only structurally but also func-
tionally: indeed, it encodes the constant expression
y
= 8 and I doubt the
perfect solution found later in the run will be a direct descendant of this best-
of-generation solution (indeed, the next best-of-generation has nothing in
common with this solution as the lack of homology both in the chromosome
sequence and the array of RNCs indicates). Notwithstanding, this individual
is the best of this initial population and therefore will be cloned unchanged
into the next generation.
a.
01234567890123456789012
+/?aa*-??????aa70225088
b.
ET
C = {6, 4, 2, 7, 3, 1, 6, 7, 1, 0}
7
y
8
c.
a
a
Figure 5.9.
Best individual of generation 0 (chromosome 19). It has a fitness of
842.5013 evaluated against the set of fitness cases presented in Table 3.2.
a)
The
chromosome of the individual with its random numerical constants.
b)
The fully
expressed individual, which means that the constants themselves and not their
symbols are shown in the expression tree; coincidentally, in this case, the numeral
“7” in the Dc corresponds to the numerical constant 7.
c)
The corresponding
mathematical expression.
In the next generation there was no improvement in best fitness and the
best two individuals of this generation are the clone of the best individual of
the initial population and a major variant of this individual (both these chro-
mosomes are shown in bold):
Generation N: 1
01234567890123456789012
+/?aa*-??????aa70225088-{6,4,2,7,3,1,6,7,1,0}-[ 0] = 842.5013
+*++++/????a?aa00881894-{2,4,5,4,0,6,3,4,2,9}-[ 1] = 828.4936
//*?+++aa??a???70216547-{7,9,3,8,7,8,0,2,7,5}-[ 2] = 821.6634
//*++++aa??a???82565470-{7,9,3,8,7,8,0,2,7,5}-[ 3] = 820.4595
-a-+a+??aaaaa??76298438-{6,5,4,6,8,9,1,5,3,2}-[ 4] = 760.5252
+*++++/??a?????76298538-{2,4,5,4,0,6,3,4,2,9}-[ 5] = 623.6609
-/?+?*/??a????a29276817-{6,0,0,7,0,7,0,4,8,4}-[ 6] = 0
*--?++aaaa???aa70225088-{2,7,5,3,8,8,9,8,1,2}-[ 7] = 634.9871
