import numpy as np
[docs]def tour_select(fitness, tournament_size):
"""Tournament selection. Choose number of individuals to participate
and select the one with the best fitness.
Parameters
----------
fitness : array_like
An array of each individual's fitness.
tournament_size : int
Number of participants in the tournament.
Returns
-------
int
The index of the best individual.
"""
aspirants = np.random.choice(len(fitness)-1, tournament_size, replace=False)
chosen = []
for ind in aspirants:
chosen.append([ind, fitness[ind]])
chosen.sort(key=lambda x: x[1])
return chosen[0][0]
