Question about MessagePassing network's GCN implementation

[hydra324]

The normalization step in GCN implementation using message passing base class uses row,col = edge_index in the documentation. What exactly does this do?

[rusty1s]

edge_index denotes a COO tensor, i.e. it holds pairs of source and destination node indices. row refers to all the source node indices, and col refers to all the destination node indices.

[hydra324]

So, I think for an undirected graph, it shouldn't matter whether I compute degree using row or col. Thank you.