docs: def build_sample_ace_problem_wang04(N=100):
      """Build sample problem from Wang 2004."""
      x = [numpy.random.uniform(-1, 1, size=N)
           for _i in range(0, 5)]
      noise = numpy.random.standard_normal(N)
      y = numpy.log(4.0 + numpy.sin(4 * x[0]) + numpy.abs(x[1]) + x[2] ** 2 +
                    x[3] ** 3 + x[4] + 0.1 * noise)
      return x, y