def cmp_individual_scaled(a, b):
   """ Compares two individual fitness scores, used for sorting population

   Example:
      >>> GPopulation.cmp_individual_scaled(a, b)
   
   :param a: the A individual instance
   :param b: the B individual instance
   :rtype: 0 if the two individuals fitness score are the same,
           -1 if the B individual fitness score is greater than A and
           1 if the A individual fitness score is greater than B.

   .. note:: this function is used to sorte the population individuals

   """
   if a.fitness < b.fitness: return -1
   if a.fitness > b.fitness: return 1
   return 0