Returns indices of the triangles containing lons / lats.

        Parameters
        ----------
         lons : float / array of floats, shape (l,)
            longitudinal coordinate(s) on the sphere
         lats : float / array of floats, shape (l,)
            latitudinal coordinate(s) on the sphere

        Returns
        -------
         tri_indices : array of ints, shape (l,)


        Notes
        -----
          The simplices are found as spherical.sTriangulation.simplices[tri_indices]

def containing_triangle(self, lons, lats):
        """
        Returns indices of the triangles containing lons / lats.

        Parameters
        ----------
         lons : float / array of floats, shape (l,)
            longitudinal coordinate(s) on the sphere
         lats : float / array of floats, shape (l,)
            latitudinal coordinate(s) on the sphere

        Returns
        -------
         tri_indices : array of ints, shape (l,)


        Notes
        -----
          The simplices are found as spherical.sTriangulation.simplices[tri_indices]

        """
        p = self._permutation
        pts = np.array(lonlat2xyz(lons,lats)).T

        sorted_simplices = np.sort(self._simplices, axis=1)

        triangles = []
        for pt in pts:
            t = _stripack.trfind(3, pt, self._x, self._y, self._z, self.lst, self.lptr, self.lend )
            tri = np.sort(t[3:6]) - 1

            triangles.append(np.where(np.all(p[sorted_simplices]==p[tri], axis=1))[0])

        return np.array(triangles).reshape(-1)