We therefore propose that all node feature vectors are updated according to an identical convolution (or message passing) function, but that neighbor lists for v i and v pi differ in construction and are directed. Specifically, a crystal node's neighbor list only consists of other crystal nodes, {v j ∈ V}, while a path image node's neighbor list may consist of any nodes (either image or crystal), {v j ∈ V ∪ P}. A series of t convolution functions, f (t) conv , are identically applied to update both crystal and path image nodes,