In the original PiNet, we reformulated the CGNN as pairwise interaction (PI) operations and interaction pooling (IP) operations. The initial and invariant (n = 1) atomic property n P i is generated using either the nuclear charge Z i or one-hot embedding. The invariant (n = 1) pairwise interaction n I ij is a function of the ini- tial atomic properties of two atoms and their distance r ij :