Information Technology Reference
In-Depth Information
-a+/a+aaaaaaa--*a/+aaaaaaa-**-+aaaaaaaa-/+++/aaaaaaa-[15] = 420.3384
//+a-*aaaaaaa/a-a*+aaaaaaa**+/-aaaaaaaa/+-a/-aaaaaaa-[16] = 0
+-aa/+aaaaaaa-*-**aaaaaaaa*//*-/aaaaaaa*+*a/aaaaaaaa-[17] = 0
*/-+a*aaaaaaa+*-+-/aaaaaaa/a-//aaaaaaaa-+-/+aaaaaaaa-[18] = 0
+-++a-aaaaaaa+-a*-aaaaaaaa/*a---aaaaaaa+*a+a*aaaaaaa-[19] = 789.56
+*aa++aaaaaaa*++a+/aaaaaaa+*/**/aaaaaaa*/*/*-aaaaaaa-[20] = 171.441
/a**a/aaaaaaa*+-++/aaaaaaa*//-++aaaaaaa----/-aaaaaaa-[21] = 403.2058
+a*--aaaaaaaa+/-//-aaaaaaa--++a*aaaaaaa+***aaaaaaaaa-[22] = 779.5309
*////*aaaaaaa-//-a/aaaaaaa/*/a-+aaaaaaa+-/*+*aaaaaaa-[23] = 296.2591
/a-++-aaaaaaa+-**a*aaaaaaa*+-a*aaaaaaaa-/+aa-aaaaaaa-[24] = 873.554
*a++/aaaaaaaa/-a--*aaaaaaa***a+/aaaaaaa*/*+a-aaaaaaa-[25] = 313.3738
-++/+/aaaaaaa*+a+*/aaaaaaa/+-+-/aaaaaaa-+//a+aaaaaaa-[26] = 908.0693
*/***/aaaaaaa+-*---aaaaaaa/+a/a*aaaaaaa*+*+/*aaaaaaa-[27] = 195.4805
+*a+/aaaaaaaa**a+-*aaaaaaa/*+a+/aaaaaaa+***a-aaaaaaa-[28] = 748.5801
-/---+aaaaaaa//+*+-aaaaaaa-/---aaaaaaaa+-++*-aaaaaaa-[29] = 0
Note that eight of the 30 randomly generated individuals are unviable,
that is, have zero fitness. This means that, either they were unable to solve a
single fitness case within the chosen selection range, or they returned math-
ematical errors such as a division by zero. As you can easily check, in this
case, the reason why they all received zero fitness is that they all perform
divisions by zero.
Consider, for instance, the best individual of this generation, chromosome
26, with fitness 908.0693:
0123456789012012345678901201234567890120123456789012
-++/+/aaaaaaa*+a+*/aaaaaaa/+-+-/aaaaaaa-+//a+aaaaaaa
(4.2a)
As its expression shows, two of the four terms of the target function (the first
and second terms) are already present in this solution (the contribution of
each gene is shown in brackets):
2
a
§
·
3
2
y
(
a
)
(
a
a
a
)
(
a
1
©
¹
(4.2b)
1
a
In the next generation (generation 1) a new individual with better traits
than the best individual of generation 0 was created:
0123456789012012345678901201234567890120123456789012
+a+*-aaaaaaaa+/-//-aaaaaaa--++a*aaaaaaa+***aaaaaaaaa
(4.3a)
It has a fitness of 958.3982 evaluated against the set of fitness cases pre-
sented in Table 4.2. Its expression shows that three of the terms of this inter-
mediate solution match exactly the target function (4.1); in fact, only the
third term is missing (the contribution of each gene is shown in brackets):
y
(
a
2
a
)
(
a
)
(
a
2
)
(
a
3
a
2
)
(4.3b)
