import math


def deb01(ind):
    """Deb01 function defined as:
    $$ f(x) = - \frac{1}{n} \sum_{i=1}^{n} \sin(5 \pi x_i)^6 $$
    with a search domain of $-1 < x_i < 1, 1 \leq i \leq n$.
    """
    return -sum(( math.sin(5. * math.pi * ind[i])**6. for i in range(len(ind)))) / float(len(ind)),