Figure 4:

Message passing aggregation phase. Taking atom 4 as an example, atom 3 and atom 5 are its neighbors. In the passing process, the message of atom 3 and atom 5 from previous passing step will be aggregated to atom 4. For the message construction, we take atom 3 as an example. The message $m_3^d$ of atom 3 is concatenated by the initial atom features $h_3^d$ of atom 3, as well as the initial bond features µ₃₄ of the connected bond 34.