code: def parametric_mapping(vals):
      """
      Parametrization of the surface x**2-y**2*z**2+z**3=0
      """
      u = vals[:, 0]
      v = vals[:, 1]
      o = np.array([v * (u**2 - v**2), u, u**2 - v**2]).T
      return o
  
file_path: nipy/nipy/core/reference/tests/test_parametrized_surface.py
imports: import numpy
  from nipy.core.api import CoordinateMap, CoordinateSystem, Grid
label_desc: Use image node_id 1 for calling a global function with example usage: parametric_mapping(vals) and returns: o