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composed of more than one multigene family are used. Indeed, the task as-
signment problem is solved very efficiently using only inversion as the source
of genetic variation and two multigene families: one to encode the assistants
(represented by 1-6) and another to encode the topic collections (represented
by A-F). Such a chromosome is shown below:
012345
012345
652314
DECFAB
(11.12)
It contains two different MGFs, the first encoding the assistants and the sec-
ond the topic collections. And its expression gives:
6
D
5
E
2
C
F
3
1
A
4
B
where the assignments are represented by the arrows. As you can easily
check in Figure 11.7, this individual has
f
i
= 41.
So, for the task assignment problem, we are going to use small populations
of 30 individuals and evolutionary times of 50 generations. The parameters
used per run and the performance of the algorithm expressed in terms of
success rate are shown in Table 11.2.
Table 11.2
Parameters for the task assignment problem.
Number of runs
100
Number of generations
50
Population size
30
Number of multigene families
2
Number of genes per multigene family
6
Chromosome length
12
Inversion rate
0.30
Success rate
69%
