How to transform directed graph to undirected graph?

[GeorgeScrivener]

I have a directed graph and need to view it as an undirected graph. Is this implemented already or do I need to create my own adaptor?

[jmcomets]

Could you provide some details on what you mean by "viewing it as an undirected graph"?

If you're speaking of an adapter for traversals & other algorithms, then no it isn't implemented.

[GeorgeScrivener]

Yeah I meant an adaptor so I can pass my directed graph in to algorithms and have them treat it as an undirected graph.
I'm happy to make a PR for this if you think it would be useful? I think that copying Reversed would be a good start.

[jmcomets]

I'd definitely welcome that! Note that there's quite a few traits that you need to implement for most algorithms to work. I agree that copying Reversed is a good start. 👍

[timthelion]

FYI you can do this very simply right now with an unsafe transmute: https://timothy.hobbs.cz/rust-play/petgraph-internals.html#The-Graph-data-structure

let undirected_tree : Graph<&str, &str, petgraph::Undirected> = unsafe {std::mem::transmute(tree.clone())};

[GeorgeScrivener]

I'm having a look at this now and I'm unsure whether I should implement IntoNeighborsDirected for the UndirectedAdaptor (proposed name)?
Intuitively I'd say that it shouldn't be implemented as it is always undirected, however it is implemented for Graph whether or not the edges are directed.
@jmcomets what's your view on this?

[GeorgeScrivener]

PR for this here: #318