Struct StableGraph

pub struct StableGraph<N, E, Ty = Directed, Ix = DefaultIx> { /* private fields */ }

StableGraph<N, E, Ty, Ix> is a graph datastructure using an adjacency list representation.

The graph does not invalidate any unrelated node or edge indices when items are removed.

StableGraph is parameterized over:

• Associated data N for nodes and E for edges, also called weights. The associated data can be of arbitrary type.
• Edge type Ty that determines whether the graph edges are directed or undirected.
• Index type Ix, which determines the maximum size of the graph.

The graph uses O(|V| + |E|) space, and allows fast node and edge insert and efficient graph search.

It implements O(e’) edge lookup and edge and node removals, where e’ is some local measure of edge count.

• Nodes and edges are each numbered in an interval from 0 to some number m, but not all indices in the range are valid, since gaps are formed by deletions.

• You can select graph index integer type after the size of the graph. A smaller size may have better performance.

• Using indices allows mutation while traversing the graph, see Dfs.

• The StableGraph is a regular rust collection and is Send and Sync (as long as associated data N and E are).

• Indices don’t allow as much compile time checking as references.

Depends on crate feature stable_graph (default). Stable Graph is still missing a few methods compared to Graph. You can contribute to help it achieve parity.

Implementations

impl<N, E> StableGraph<N, E, Directed>

pub fn new() -> Self

Create a new StableGraph with directed edges.

This is a convenience method. See StableGraph::with_capacity or StableGraph::default for a constructor that is generic in all the type parameters of StableGraph.

impl<N, E, Ty, Ix> StableGraph<N, E, Ty, Ix>

where Ty: EdgeType, Ix: IndexType,

pub fn with_capacity(nodes: usize, edges: usize) -> Self

Create a new StableGraph with estimated capacity.

pub fn capacity(&self) -> (usize, usize)

Return the current node and edge capacity of the graph.

pub fn reverse(&mut self)

Reverse the direction of all edges

pub fn clear(&mut self)

Remove all nodes and edges

pub fn clear_edges(&mut self)

Remove all edges

pub fn node_count(&self) -> usize

Return the number of nodes (vertices) in the graph.

Computes in O(1) time.

pub fn edge_count(&self) -> usize

Return the number of edges in the graph.

Computes in O(1) time.

pub fn is_directed(&self) -> bool

Whether the graph has directed edges or not.

pub fn add_node(&mut self, weight: N) -> NodeIndex<Ix>

Add a node (also called vertex) with associated data weight to the graph.

Computes in O(1) time.

Return the index of the new node.

Panics if the StableGraph is at the maximum number of nodes for its index type.

pub fn remove_node(&mut self, a: NodeIndex<Ix>) -> Option<N>

Remove a from the graph if it exists, and return its weight. If it doesn’t exist in the graph, return None.

The node index a is invalidated, but none other. Edge indices are invalidated as they would be following the removal of each edge with an endpoint in a.

Computes in O(e’) time, where e’ is the number of affected edges, including n calls to .remove_edge() where n is the number of edges with an endpoint in a.

pub fn contains_node(&self, a: NodeIndex<Ix>) -> bool

pub fn add_edge( &mut self, a: NodeIndex<Ix>, b: NodeIndex<Ix>, weight: E, ) -> EdgeIndex<Ix>

Add an edge from a to b to the graph, with its associated data weight.

Return the index of the new edge.

Computes in O(1) time.

Panics if any of the nodes don’t exist.
Panics if the StableGraph is at the maximum number of edges for its index type.

Note: StableGraph allows adding parallel (“duplicate”) edges.

pub fn update_edge( &mut self, a: NodeIndex<Ix>, b: NodeIndex<Ix>, weight: E, ) -> EdgeIndex<Ix>

Add or update an edge from a to b. If the edge already exists, its weight is updated.

Return the index of the affected edge.

Computes in O(e’) time, where e’ is the number of edges connected to a (and b, if the graph edges are undirected).

Panics if any of the nodes don’t exist.

pub fn remove_edge(&mut self, e: EdgeIndex<Ix>) -> Option<E>

Remove an edge and return its edge weight, or None if it didn’t exist.

Invalidates the edge index e but no other.

Computes in O(e’) time, where e’ is the number of edges connected to the same endpoints as e.

pub fn node_weight(&self, a: NodeIndex<Ix>) -> Option<&N>

Access the weight for node a.

Also available with indexing syntax: &graph[a].

pub fn node_weight_mut(&mut self, a: NodeIndex<Ix>) -> Option<&mut N>

Access the weight for node a, mutably.

Also available with indexing syntax: &mut graph[a].

pub fn node_weights(&self) -> impl Iterator<Item = &N>

Return an iterator yielding immutable access to all node weights.

The order in which weights are yielded matches the order of their node indices.

pub fn node_weights_mut(&mut self) -> impl Iterator<Item = &mut N>

Return an iterator yielding mutable access to all node weights.

The order in which weights are yielded matches the order of their node indices.

pub fn node_indices(&self) -> NodeIndices<'_, N, Ix>

Return an iterator over the node indices of the graph

pub fn edge_weight(&self, e: EdgeIndex<Ix>) -> Option<&E>

Access the weight for edge e.

Also available with indexing syntax: &graph[e].

pub fn edge_weight_mut(&mut self, e: EdgeIndex<Ix>) -> Option<&mut E>

Access the weight for edge e, mutably

Also available with indexing syntax: &mut graph[e].

pub fn edge_weights(&self) -> impl Iterator<Item = &E>

Return an iterator yielding immutable access to all edge weights.

The order in which weights are yielded matches the order of their edge indices.

pub fn edge_weights_mut(&mut self) -> impl Iterator<Item = &mut E>

Return an iterator yielding mutable access to all edge weights.

The order in which weights are yielded matches the order of their edge indices.

pub fn edge_endpoints( &self, e: EdgeIndex<Ix>, ) -> Option<(NodeIndex<Ix>, NodeIndex<Ix>)>

Access the source and target nodes for e.

pub fn edge_indices(&self) -> EdgeIndices<'_, E, Ix>

Return an iterator over the edge indices of the graph

pub fn edges_connecting( &self, a: NodeIndex<Ix>, b: NodeIndex<Ix>, ) -> EdgesConnecting<'_, E, Ty, Ix>

Return an iterator over all the edges connecting a and b.

• Directed: Outgoing edges from a.
• Undirected: All edges connected to a.

Iterator element type is EdgeReference<E, Ix>.

pub fn contains_edge(&self, a: NodeIndex<Ix>, b: NodeIndex<Ix>) -> bool

Lookup if there is an edge from a to b.

Computes in O(e’) time, where e’ is the number of edges connected to a (and b, if the graph edges are undirected).

pub fn find_edge( &self, a: NodeIndex<Ix>, b: NodeIndex<Ix>, ) -> Option<EdgeIndex<Ix>>

Lookup an edge from a to b.

Computes in O(e’) time, where e’ is the number of edges connected to a (and b, if the graph edges are undirected).

pub fn find_edge_undirected( &self, a: NodeIndex<Ix>, b: NodeIndex<Ix>, ) -> Option<(EdgeIndex<Ix>, Direction)>

Lookup an edge between a and b, in either direction.

If the graph is undirected, then this is equivalent to .find_edge().

Return the edge index and its directionality, with Outgoing meaning from a to b and Incoming the reverse, or None if the edge does not exist.

pub fn neighbors(&self, a: NodeIndex<Ix>) -> Neighbors<'_, E, Ix>

Return an iterator of all nodes with an edge starting from a.

• Directed: Outgoing edges from a.
• Undirected: All edges connected to a.

Produces an empty iterator if the node doesn’t exist.
Iterator element type is NodeIndex<Ix>.

Use .neighbors(a).detach() to get a neighbor walker that does not borrow from the graph.

pub fn neighbors_directed( &self, a: NodeIndex<Ix>, dir: Direction, ) -> Neighbors<'_, E, Ix>

Return an iterator of all neighbors that have an edge between them and a, in the specified direction. If the graph’s edges are undirected, this is equivalent to .neighbors(a).

• Directed, Outgoing: All edges from a.
• Directed, Incoming: All edges to a.
• Undirected: All edges connected to a.

Produces an empty iterator if the node doesn’t exist.
Iterator element type is NodeIndex<Ix>.

Use .neighbors_directed(a, dir).detach() to get a neighbor walker that does not borrow from the graph.

pub fn neighbors_undirected(&self, a: NodeIndex<Ix>) -> Neighbors<'_, E, Ix>

Return an iterator of all neighbors that have an edge between them and a, in either direction. If the graph’s edges are undirected, this is equivalent to .neighbors(a).

• Directed and Undirected: All edges connected to a.

Produces an empty iterator if the node doesn’t exist.
Iterator element type is NodeIndex<Ix>.

Use .neighbors_undirected(a).detach() to get a neighbor walker that does not borrow from the graph.

pub fn edges(&self, a: NodeIndex<Ix>) -> Edges<'_, E, Ty, Ix>

Return an iterator of all edges of a.

• Directed: Outgoing edges from a.
• Undirected: All edges connected to a.

Produces an empty iterator if the node doesn’t exist.
Iterator element type is EdgeReference<E, Ix>.

pub fn edges_directed( &self, a: NodeIndex<Ix>, dir: Direction, ) -> Edges<'_, E, Ty, Ix>

Return an iterator of all edges of a, in the specified direction.

• Directed, Outgoing: All edges from a.
• Directed, Incoming: All edges to a.
• Undirected, Outgoing: All edges connected to a, with a being the source of each edge.
• Undirected, Incoming: All edges connected to a, with a being the target of each edge.

Produces an empty iterator if the node a doesn’t exist.
Iterator element type is EdgeReference<E, Ix>.

pub fn externals(&self, dir: Direction) -> Externals<'_, N, Ty, Ix>

Return an iterator over either the nodes without edges to them (Incoming) or from them (Outgoing).

An internal node has both incoming and outgoing edges. The nodes in .externals(Incoming) are the source nodes and .externals(Outgoing) are the sinks of the graph.

For a graph with undirected edges, both the sinks and the sources are just the nodes without edges.

The whole iteration computes in O(|V|) time.

pub fn index_twice_mut<T, U>( &mut self, i: T, j: U, ) -> (&mut <Self as Index<T>>::Output, &mut <Self as Index<U>>::Output)

where Self: IndexMut<T> + IndexMut<U>, T: GraphIndex, U: GraphIndex,

Index the StableGraph by two indices, any combination of node or edge indices is fine.

Panics if the indices are equal or if they are out of bounds.

pub fn retain_nodes<F>(&mut self, visit: F)

where F: FnMut(Frozen<'_, Self>, NodeIndex<Ix>) -> bool,

Keep all nodes that return true from the visit closure, remove the others.

visit is provided a proxy reference to the graph, so that the graph can be walked and associated data modified.

The order nodes are visited is not specified.

The node indices of the removed nodes are invalidated, but none other. Edge indices are invalidated as they would be following the removal of each edge with an endpoint in a removed node.

Computes in O(n + e’) time, where n is the number of node indices and e’ is the number of affected edges, including n calls to .remove_edge() where n is the number of edges with an endpoint in a removed node.

pub fn retain_edges<F>(&mut self, visit: F)

where F: FnMut(Frozen<'_, Self>, EdgeIndex<Ix>) -> bool,

Keep all edges that return true from the visit closure, remove the others.

visit is provided a proxy reference to the graph, so that the graph can be walked and associated data modified.

The order edges are visited is not specified.

The edge indices of the removed edes are invalidated, but none other.

Computes in O(e’‘) time, e’ is the number of affected edges, including the calls to .remove_edge() for each removed edge.

pub fn from_edges<I>(iterable: I) -> Self

where I: IntoIterator, I::Item: IntoWeightedEdge<E>, <I::Item as IntoWeightedEdge<E>>::NodeId: Into<NodeIndex<Ix>>, N: Default,

Create a new StableGraph from an iterable of edges.

Node weights N are set to default values. Edge weights E may either be specified in the list, or they are filled with default values.

Nodes are inserted automatically to match the edges.

use petgraph::stable_graph::StableGraph;

let gr = StableGraph::<(), i32>::from_edges(&[
    (0, 1), (0, 2), (0, 3),
    (1, 2), (1, 3),
    (2, 3),
]);

pub fn map<'a, F, G, N2, E2>( &'a self, node_map: F, edge_map: G, ) -> StableGraph<N2, E2, Ty, Ix>

where F: FnMut(NodeIndex<Ix>, &'a N) -> N2, G: FnMut(EdgeIndex<Ix>, &'a E) -> E2,

Create a new StableGraph by mapping node and edge weights to new values.

The resulting graph has the same structure and the same graph indices as self.

pub fn filter_map<'a, F, G, N2, E2>( &'a self, node_map: F, edge_map: G, ) -> StableGraph<N2, E2, Ty, Ix>

where F: FnMut(NodeIndex<Ix>, &'a N) -> Option<N2>, G: FnMut(EdgeIndex<Ix>, &'a E) -> Option<E2>,

Create a new StableGraph by mapping nodes and edges. A node or edge may be mapped to None to exclude it from the resulting graph.

Nodes are mapped first with the node_map closure, then edge_map is called for the edges that have not had any endpoint removed.

The resulting graph has the structure of a subgraph of the original graph. Nodes and edges that are not removed maintain their old node or edge indices.

pub fn extend_with_edges<I>(&mut self, iterable: I)

where I: IntoIterator, I::Item: IntoWeightedEdge<E>, <I::Item as IntoWeightedEdge<E>>::NodeId: Into<NodeIndex<Ix>>, N: Default,

Extend the graph from an iterable of edges.

Node weights N are set to default values. Edge weights E may either be specified in the list, or they are filled with default values.

Nodes are inserted automatically to match the edges.

Trait Implementations

impl<N, E, Ty, Ix> Build for StableGraph<N, E, Ty, Ix>

where Ty: EdgeType, Ix: IndexType,

fn add_node(&mut self, weight: Self::NodeWeight) -> Self::NodeId

fn add_edge( &mut self, a: Self::NodeId, b: Self::NodeId, weight: Self::EdgeWeight, ) -> Option<Self::EdgeId>

Add a new edge. If parallel edges (duplicate) are not allowed and the edge already exists, return None.

fn update_edge( &mut self, a: Self::NodeId, b: Self::NodeId, weight: Self::EdgeWeight, ) -> Self::EdgeId

Add or update the edge from a to b. Return the id of the affected edge.

impl<N, E, Ty, Ix: IndexType> Clone for StableGraph<N, E, Ty, Ix>

where N: Clone, E: Clone,

The resulting cloned graph has the same graph indices as self.

fn clone(&self) -> Self

Returns a copy of the value.

fn clone_from(&mut self, rhs: &Self)

Performs copy-assignment from source.

impl<N, E, Ty, Ix> Create for StableGraph<N, E, Ty, Ix>

where Ty: EdgeType, Ix: IndexType,

fn with_capacity(nodes: usize, edges: usize) -> Self

impl<N, E, Ty, Ix> Data for StableGraph<N, E, Ty, Ix>

where Ty: EdgeType, Ix: IndexType,

type NodeWeight = N

type EdgeWeight = E

impl<N, E, Ty, Ix> DataMap for StableGraph<N, E, Ty, Ix>

where Ty: EdgeType, Ix: IndexType,

fn node_weight(&self, id: Self::NodeId) -> Option<&Self::NodeWeight>

fn edge_weight(&self, id: Self::EdgeId) -> Option<&Self::EdgeWeight>

impl<N, E, Ty, Ix> DataMapMut for StableGraph<N, E, Ty, Ix>

where Ty: EdgeType, Ix: IndexType,

fn node_weight_mut(&mut self, id: Self::NodeId) -> Option<&mut Self::NodeWeight>

fn edge_weight_mut(&mut self, id: Self::EdgeId) -> Option<&mut Self::EdgeWeight>

impl<N, E, Ty, Ix> Debug for StableGraph<N, E, Ty, Ix>

where N: Debug, E: Debug, Ty: EdgeType, Ix: IndexType,

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<N, E, Ty, Ix> Default for StableGraph<N, E, Ty, Ix>

where Ty: EdgeType, Ix: IndexType,

Create a new empty StableGraph.

fn default() -> Self

Returns the “default value” for a type.

impl<N, E, Ty, Ix> EdgeCount for StableGraph<N, E, Ty, Ix>

where Ty: EdgeType, Ix: IndexType,

fn edge_count(&self) -> usize

Return the number of edges in the graph.

impl<N, E, Ty, Ix> EdgeIndexable for StableGraph<N, E, Ty, Ix>

where Ty: EdgeType, Ix: IndexType,

fn edge_bound(&self) -> usize

Return an upper bound of the edge indices in the graph (suitable for the size of a bitmap).

fn to_index(&self, ix: EdgeIndex<Ix>) -> usize

Convert a to an integer index.

fn from_index(&self, ix: usize) -> Self::EdgeId

Convert i to an edge index. i must be a valid value in the graph.

impl<N, E, Ty, Ix> From<Graph<N, E, Ty, Ix>> for StableGraph<N, E, Ty, Ix>

where Ty: EdgeType, Ix: IndexType,

Convert a Graph into a StableGraph

Computes in O(|V| + |E|) time.

The resulting graph has the same node and edge indices as the original graph.

fn from(g: Graph<N, E, Ty, Ix>) -> Self

Converts to this type from the input type.

impl<N, E, Ty, Ix> From<StableGraph<N, E, Ty, Ix>> for Graph<N, E, Ty, Ix>

where Ty: EdgeType, Ix: IndexType,

Convert a StableGraph into a Graph

Computes in O(|V| + |E|) time.

This translates the stable graph into a graph with node and edge indices in a compact interval without holes (like Graphs always are).

Only if the stable graph had no vacancies after deletions (if node bound was equal to node count, and the same for edges), would the resulting graph have the same node and edge indices as the input.

fn from(graph: StableGraph<N, E, Ty, Ix>) -> Self

Converts to this type from the input type.

impl<N, E, Ty, Ix> FromElements for StableGraph<N, E, Ty, Ix>

where Ty: EdgeType, Ix: IndexType,

fn from_elements<I>(iterable: I) -> Self

where Self: Sized, I: IntoIterator<Item = Element<Self::NodeWeight, Self::EdgeWeight>>,

impl<N, E, Ty, Ix> GetAdjacencyMatrix for StableGraph<N, E, Ty, Ix>

where Ty: EdgeType, Ix: IndexType,

The adjacency matrix for Graph is a bitmap that’s computed by .adjacency_matrix().

type AdjMatrix = FixedBitSet

The associated adjacency matrix type

fn adjacency_matrix(&self) -> FixedBitSet

Create the adjacency matrix

fn is_adjacent( &self, matrix: &FixedBitSet, a: NodeIndex<Ix>, b: NodeIndex<Ix>, ) -> bool

Return true if there is an edge from a to b, false otherwise.

impl<N, E, Ty, Ix> GraphBase for StableGraph<N, E, Ty, Ix>

where Ix: IndexType,

type NodeId = NodeIndex<Ix>

node identifier

type EdgeId = EdgeIndex<Ix>

edge identifier

impl<N, E, Ty, Ix> GraphProp for StableGraph<N, E, Ty, Ix>

where Ty: EdgeType, Ix: IndexType,

type EdgeType = Ty

The kind of edges in the graph.

fn is_directed(&self) -> bool

impl<N, E, Ty, Ix> Index<EdgeIndex<Ix>> for StableGraph<N, E, Ty, Ix>

where Ty: EdgeType, Ix: IndexType,

Index the StableGraph by EdgeIndex to access edge weights.

Panics if the edge doesn’t exist.

type Output = E

The returned type after indexing.

fn index(&self, index: EdgeIndex<Ix>) -> &E

Performs the indexing (container[index]) operation.

impl<N, E, Ty, Ix> Index<NodeIndex<Ix>> for StableGraph<N, E, Ty, Ix>

where Ty: EdgeType, Ix: IndexType,

Index the StableGraph by NodeIndex to access node weights.

Panics if the node doesn’t exist.

type Output = N

The returned type after indexing.

fn index(&self, index: NodeIndex<Ix>) -> &N

Performs the indexing (container[index]) operation.

impl<N, E, Ty, Ix> IndexMut<EdgeIndex<Ix>> for StableGraph<N, E, Ty, Ix>

where Ty: EdgeType, Ix: IndexType,

Index the StableGraph by EdgeIndex to access edge weights.

Panics if the edge doesn’t exist.

fn index_mut(&mut self, index: EdgeIndex<Ix>) -> &mut E

Performs the mutable indexing (container[index]) operation.

impl<N, E, Ty, Ix> IndexMut<NodeIndex<Ix>> for StableGraph<N, E, Ty, Ix>

where Ty: EdgeType, Ix: IndexType,

Index the StableGraph by NodeIndex to access node weights.

Panics if the node doesn’t exist.

fn index_mut(&mut self, index: NodeIndex<Ix>) -> &mut N

Performs the mutable indexing (container[index]) operation.

impl<'a, N: 'a, E: 'a, Ty, Ix> IntoEdgeReferences for &'a StableGraph<N, E, Ty, Ix>

where Ty: EdgeType, Ix: IndexType,

fn edge_references(self) -> Self::EdgeReferences

Create an iterator over all edges in the graph, in indexed order.

Iterator element type is EdgeReference<E, Ix>.

type EdgeRef = EdgeReference<'a, E, Ix>

type EdgeReferences = EdgeReferences<'a, E, Ix>

impl<'a, N, E, Ty, Ix> IntoEdges for &'a StableGraph<N, E, Ty, Ix>

where Ty: EdgeType, Ix: IndexType,

type Edges = Edges<'a, E, Ty, Ix>

fn edges(self, a: Self::NodeId) -> Self::Edges

impl<'a, N, E, Ty, Ix> IntoEdgesDirected for &'a StableGraph<N, E, Ty, Ix>

where Ty: EdgeType, Ix: IndexType,

type EdgesDirected = Edges<'a, E, Ty, Ix>

fn edges_directed(self, a: Self::NodeId, dir: Direction) -> Self::EdgesDirected

impl<'a, N, E: 'a, Ty, Ix> IntoNeighbors for &'a StableGraph<N, E, Ty, Ix>

where Ty: EdgeType, Ix: IndexType,

type Neighbors = Neighbors<'a, E, Ix>

fn neighbors(self, n: Self::NodeId) -> Self::Neighbors

Return an iterator of the neighbors of node a.

impl<'a, N, E: 'a, Ty, Ix> IntoNeighborsDirected for &'a StableGraph<N, E, Ty, Ix>

where Ty: EdgeType, Ix: IndexType,

type NeighborsDirected = Neighbors<'a, E, Ix>

fn neighbors_directed( self, n: NodeIndex<Ix>, d: Direction, ) -> Self::NeighborsDirected

impl<'a, N, E: 'a, Ty, Ix> IntoNodeIdentifiers for &'a StableGraph<N, E, Ty, Ix>

where Ty: EdgeType, Ix: IndexType,

type NodeIdentifiers = NodeIndices<'a, N, Ix>

fn node_identifiers(self) -> Self::NodeIdentifiers

impl<'a, N, E, Ty, Ix> IntoNodeReferences for &'a StableGraph<N, E, Ty, Ix>

where Ty: EdgeType, Ix: IndexType,

type NodeRef = (NodeIndex<Ix>, &'a N)

type NodeReferences = NodeReferences<'a, N, Ix>

fn node_references(self) -> Self::NodeReferences

impl<N, E, Ty, Ix> NodeCount for StableGraph<N, E, Ty, Ix>

where Ty: EdgeType, Ix: IndexType,

fn node_count(&self) -> usize

impl<N, E, Ty, Ix> NodeIndexable for StableGraph<N, E, Ty, Ix>

where Ty: EdgeType, Ix: IndexType,

fn node_bound(&self) -> usize

Return an upper bound of the node indices in the graph

fn to_index(&self, ix: NodeIndex<Ix>) -> usize

Convert a to an integer index.

fn from_index(&self, ix: usize) -> Self::NodeId

Convert i to a node index. i must be a valid value in the graph.

impl<N, E, Ty, Ix> Visitable for StableGraph<N, E, Ty, Ix>

where Ty: EdgeType, Ix: IndexType,

type Map = FixedBitSet

The associated map type

fn visit_map(&self) -> FixedBitSet

Create a new visitor map

fn reset_map(&self, map: &mut Self::Map)

Reset the visitor map (and resize to new size of graph if needed)