def nn_interpolator(self, z, default_value=np.nan):
z = np.asarray(z, dtype=np.float64)<EOL>if z.shape != self.old_shape:<EOL><INDENT>raise ValueError("<STR_LIT>")<EOL><DEDENT>if self.j_unique is not None:<EOL><INDENT>z = z[self.j_unique]<EOL><DEDENT>return NNInterpolator(self, z, default_value)<EOL>
Get an object which can interpolate within the convex hull by
        the natural neighbors method.

        z -- an array of floats giving the known function values at each point
          in the triangulation.