RandomLinkSplit with rev_edge_types and undirected=True

[denadai2]

Dear community,
I am using RandomLinkSplit with rev_edge_types ('book', 'rev_co-read', 'book'), and undirected=True. I do not understand what's happening at this point of the code:

pytorch_geometric/torch_geometric/transforms/random_link_split.py

Line 273 in 60a2948

edge_index = torch.cat([edge_index, edge_index.flip([0])], dim=-1)

Why do we do so, if we have rev_edges in hetero graphs? Why is it needed?

thank you!

[rusty1s]

Mh, I agree. It is a bit misleading. Currently, the undirected=True option assumes that a single edge type holds bidirectional edges. As such, we undirected=False internally whenever the edge type models a bipartite graph, or whenever edge_type != rev_edge_type.

[denadai2]

thanks!