code: def grid_to_eccentric_radii(self, grid):
          
          return np.multiply(np.sqrt(self.axis_ratio), self.grid_to_elliptical_radii(grid)).view(np.ndarray)
docs: Convert a grid of (y,x) coordinates to an eccentric radius, which is (1.0/axis_ratio) * elliptical radius \
          and used to define light profile half-light radii using circular radii.
  
          If the coordinates have not been transformed to the profile's geometry, this is performed automatically.
  
          Parameters
          ----------
          grid : TransformedGrid(ndarray)
              The (y, x) coordinates in the reference frame of the elliptical profile.