def thcf(x):
    """Standard equation of the Three-Hump Camel Function.
    """
    eqn = 2 * (x[0] ** 2) - 1.05 * (x[0] ** 4) + \
        (x[0] ** 6) / 6 + x[0] * x[1] + (x[1] ** 2)
    return eqn                                      # Function to minimise