Struct petgraph::stable_graph::WalkNeighbors
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pub struct WalkNeighbors<Ix> { /* fields omitted */ }
A “walker” object that can be used to step through the edge list of a node.
See .detach() for more information.
The walker does not borrow from the graph, so it lets you step through neighbors or incident edges while also mutating graph weights, as in the following example:
use petgraph::visit::Dfs; use petgraph::Incoming; use petgraph::stable_graph::StableGraph; let mut gr = StableGraph::new(); let a = gr.add_node(0.); let b = gr.add_node(0.); let c = gr.add_node(0.); gr.add_edge(a, b, 3.); gr.add_edge(b, c, 2.); gr.add_edge(c, b, 1.); // step through the graph and sum incoming edges into the node weight let mut dfs = Dfs::new(&gr, a); while let Some(node) = dfs.next(&gr) { // use a detached neighbors walker let mut edges = gr.neighbors_directed(node, Incoming).detach(); while let Some(edge) = edges.next_edge(&gr) { gr[node] += gr[edge]; } } // check the result assert_eq!(gr[a], 0.); assert_eq!(gr[b], 4.); assert_eq!(gr[c], 2.);
Methods
impl<Ix: IndexType> WalkNeighbors<Ix>
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pub fn next<N, E, Ty: EdgeType>(
&mut self,
g: &StableGraph<N, E, Ty, Ix>
) -> Option<(EdgeIndex<Ix>, NodeIndex<Ix>)>
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&mut self,
g: &StableGraph<N, E, Ty, Ix>
) -> Option<(EdgeIndex<Ix>, NodeIndex<Ix>)>
Step to the next edge and its endpoint node in the walk for graph g
.
The next node indices are always the others than the starting point
where the WalkNeighbors
value was created.
For an Outgoing
walk, the target nodes,
for an Incoming
walk, the source nodes of the edge.
pub fn next_node<N, E, Ty: EdgeType>(
&mut self,
g: &StableGraph<N, E, Ty, Ix>
) -> Option<NodeIndex<Ix>>
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&mut self,
g: &StableGraph<N, E, Ty, Ix>
) -> Option<NodeIndex<Ix>>
pub fn next_edge<N, E, Ty: EdgeType>(
&mut self,
g: &StableGraph<N, E, Ty, Ix>
) -> Option<EdgeIndex<Ix>>
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&mut self,
g: &StableGraph<N, E, Ty, Ix>
) -> Option<EdgeIndex<Ix>>