where W and b are learnable weights from the network, j l is the spherical Bessel function with the roots at z ln , r c is the cutoff radius, Y 0 l is the spherical harmonics function with m = 0, ⊙ is the element-wise product, σ is the activation function, and f c (r) is the cutoff function at a radius, r. The cutoff function ensures that the functions vanishes smoothly at the neighbor boundary.