code: def dent(individual, lambda_=0.85):
      r"""Test problem Dent. Two-objective problem with a "dent". *individual* has
      two attributes that take values in [-1.5, 1.5].
      From: Schuetze, O., Laumanns, M., Tantar, E., Coello Coello, C.A., & Talbi, E.-G. (2010).
      Computing gap free Pareto front approximations with stochastic search algorithms.
      Evolutionary Computation, 18(1), 65--96. doi:10.1162/evco.2010.18.1.18103
  
      Note that in that paper Dent source is stated as:
      K. Witting and M. Hessel von Molo. Private communication, 2006.
      """
      d = lambda_ * exp(-((individual[0] - individual[1]) ** 2))
      f1 = (
          0.5
          * (
              sqrt(1 + (individual[0] + individual[1]) ** 2)
              + sqrt(1 + (individual[0] - individual[1]) ** 2)
              + individual[0]
              - individual[1]
          )
          + d
      )
      f2 = (
          0.5
          * (
              sqrt(1 + (individual[0] + individual[1]) ** 2)
              + sqrt(1 + (individual[0] - individual[1]) ** 2)
              - individual[0]
              + individual[1]
          )
          + d
      )
      return f1, f2
  
imports: import random
  from math import sin, cos, pi, exp, e, sqrt
  from operator import mul
  from functools import reduce
label_desc: Use image node_id 33 for calling a global function with example usage: dent(individual, lambda_) and returns: f1,  f2