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C = {62, 51, 68, 83, 86, 41, 43, 44, 9, 67}
the chromosome (9.3) above results in the following decision tree:
W
O
T
d
>
83
83
a
a
H
b
b
d
83
>
83
a
b
which can also be represented more colorfully as a conventional decision tree
(Figure 9.9). As you can easily check, it classifies correctly 13 of the 14
instances of Table 9.3.
WINDY
true
false
OUTLOOK
TEMPERATURE
sunny
overcast
rainy
d
83
>
83
HUMIDITY
Yes
No
Yes
No
d
>
83
83
Yes
No
Figure 9.9.
A more colorful rendition of the decision tree encoded in gene (9.3).
So, as you can see, every time a numeric attribute is expressed, it divides
into two different branches and, for the scheme used above, just one numeri-
cal constant is needed to grow each branch. Let's now see how these com-
plex structures grow and learn by solving the play tennis problem with both
nominal and numeric attributes.
