pub struct WalkNeighbors<Ix> { /* private fields */ }
Expand description
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.);
Implementations§
source§impl<Ix: IndexType> WalkNeighbors<Ix>
impl<Ix: IndexType> WalkNeighbors<Ix>
sourcepub fn next<N, E, Ty: EdgeType>(
&mut self,
g: &StableGraph<N, E, Ty, Ix>,
) -> Option<(EdgeIndex<Ix>, NodeIndex<Ix>)>
pub fn next<N, E, Ty: EdgeType>( &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>>
pub fn next_edge<N, E, Ty: EdgeType>( &mut self, g: &StableGraph<N, E, Ty, Ix>, ) -> Option<EdgeIndex<Ix>>
Trait Implementations§
Auto Trait Implementations§
impl<Ix> Freeze for WalkNeighbors<Ix>where
Ix: Freeze,
impl<Ix> RefUnwindSafe for WalkNeighbors<Ix>where
Ix: RefUnwindSafe,
impl<Ix> Send for WalkNeighbors<Ix>where
Ix: Send,
impl<Ix> Sync for WalkNeighbors<Ix>where
Ix: Sync,
impl<Ix> Unpin for WalkNeighbors<Ix>where
Ix: Unpin,
impl<Ix> UnwindSafe for WalkNeighbors<Ix>where
Ix: UnwindSafe,
Blanket Implementations§
source§impl<T> BorrowMut<T> for Twhere
T: ?Sized,
impl<T> BorrowMut<T> for Twhere
T: ?Sized,
source§fn borrow_mut(&mut self) -> &mut T
fn borrow_mut(&mut self) -> &mut T
Mutably borrows from an owned value. Read more
source§impl<T> CloneToUninit for Twhere
T: Clone,
impl<T> CloneToUninit for Twhere
T: Clone,
source§unsafe fn clone_to_uninit(&self, dst: *mut T)
unsafe fn clone_to_uninit(&self, dst: *mut T)
🔬This is a nightly-only experimental API. (
clone_to_uninit
)