IndexError: invalid index to scalar variable.

[ibreeden]

"fitness_function(position)" expects an array (or list or any iterable) of exactly 15 elements. When you do:

fitness_function(particle_position_vector[i])

... you are only passing one element. So I guess you have to pass the whole array, like this:

fitness_function(particle_position_vector)

Note that there have to be 15 elements, so the only correct answer to:

input("Inform the number of particles: ")

... is 15.