Struct MatrixGraph

pub struct MatrixGraph<N, E, Ty = Directed, Null: Nullable<Wrapped = E> = Option<E>, Ix = u16> { /* private fields */ }

MatrixGraph<N, E, Ty, Null> is a graph datastructure using an adjacency matrix representation.

MatrixGraph is parameterized over:

• Associated data N for nodes and E for edges, called weights. The associated data can be of arbitrary type.
• Edge type Ty that determines whether the graph edges are directed or undirected.
• Nullable type Null, which denotes the edges’ presence (defaults to Option<E>). You may specify NotZero<E> if you want to use a sentinel value (such as 0) to mark the absence of an edge.
• Index type Ix that sets the maximum size for the graph (defaults to DefaultIx).

The graph uses O(|V^2|) space, with fast edge insertion & amortized node insertion, as well as efficient graph search and graph algorithms on dense graphs.

This graph is backed by a flattened 2D array. For undirected graphs, only the lower triangular matrix is stored. Since the backing array stores edge weights, it is recommended to box large edge weights.

Implementations

impl<N, E, Ty: EdgeType, Null: Nullable<Wrapped = E>, Ix: IndexType> MatrixGraph<N, E, Ty, Null, Ix>

pub fn with_capacity(node_capacity: usize) -> Self

Create a new MatrixGraph with estimated capacity for nodes.

pub fn clear(&mut self)

Remove all nodes and 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

Return 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 MatrixGraph is at the maximum number of nodes for its index type.

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

Remove a from the graph.

Computes in O(V) time, due to the removal of edges with other nodes.

Panics if the node a does not exist.

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

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

Return the previous data, if any.

Computes in O(1) time, best case. Computes in O(|V|^2) time, worst case (matrix needs to be re-allocated).

Panics if any of the nodes don’t exist.

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

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

Computes in O(1) time, best case. Computes in O(|V|^2) time, worst case (matrix needs to be re-allocated).

Panics if any of the nodes don’t exist. Panics if an edge already exists from a to b.

Note: MatrixGraph does not allow adding parallel (“duplicate”) edges. If you want to avoid this, use .update_edge(a, b, weight) instead.

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

Remove the edge from a to b to the graph.

Panics if any of the nodes don’t exist. Panics if no edge exists between a and b.

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

Return true if there is an edge between a and b.

Panics if any of the nodes don’t exist.

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

Access the weight for node a.

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

Panics if the node doesn’t exist.

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

Access the weight for node a, mutably.

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

Panics if the node doesn’t exist.

pub fn edge_weight(&self, a: NodeIndex<Ix>, b: NodeIndex<Ix>) -> &E

Access the weight for edge e.

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

Panics if no edge exists between a and b.

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

Access the weight for edge e, mutably.

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

Panics if no edge exists between a and b.

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

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

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

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

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

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 MatrixGraph 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::matrix_graph::MatrixGraph;

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

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.

impl<N, E, Null: Nullable<Wrapped = E>, Ix: IndexType> MatrixGraph<N, E, Directed, Null, Ix>

pub fn neighbors_directed( &self, a: NodeIndex<Ix>, d: Direction, ) -> Neighbors<'_, Directed, Null, 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).

• Outgoing: All edges from a.
• Incoming: All edges to a.

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

pub fn edges_directed( &self, a: NodeIndex<Ix>, d: Direction, ) -> Edges<'_, Directed, Null, Ix>

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

• Outgoing: All edges from a.
• Incoming: All edges to a.

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

impl<N, E> MatrixGraph<N, E, Directed>

pub fn new() -> Self

Create a new MatrixGraph with directed edges.

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

impl<N, E> MatrixGraph<N, E, Undirected>

pub fn new_undirected() -> Self

Create a new MatrixGraph with undirected edges.

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

Trait Implementations

impl<N, E, Ty: EdgeType, Null: Nullable<Wrapped = E>, Ix: IndexType> Build for MatrixGraph<N, E, Ty, Null, Ix>

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: Clone, E: Clone, Ty: Clone, Null: Clone + Nullable<Wrapped = E>, Ix: Clone> Clone for MatrixGraph<N, E, Ty, Null, Ix>

fn clone(&self) -> MatrixGraph<N, E, Ty, Null, Ix>

Returns a copy of the value.

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

Performs copy-assignment from source.

impl<N, E, Ty: EdgeType, Null: Nullable<Wrapped = E>, Ix: IndexType> Data for MatrixGraph<N, E, Ty, Null, Ix>

type NodeWeight = N

type EdgeWeight = E

impl<N, E, Ty: EdgeType, Null: Nullable<Wrapped = E>, Ix: IndexType> Default for MatrixGraph<N, E, Ty, Null, Ix>

Create a new empty MatrixGraph.

fn default() -> Self

Returns the “default value” for a type.

impl<N, E, Ty: EdgeType, Null: Nullable<Wrapped = E>, Ix: IndexType> EdgeCount for MatrixGraph<N, E, Ty, Null, Ix>

fn edge_count(&self) -> usize

Return the number of edges in the graph.

impl<N, E, Ty: EdgeType, Null: Nullable<Wrapped = E>, Ix: IndexType> GetAdjacencyMatrix for MatrixGraph<N, E, Ty, Null, Ix>

type AdjMatrix = ()

The associated adjacency matrix type

fn adjacency_matrix(&self) -> Self::AdjMatrix

Create the adjacency matrix

fn is_adjacent( &self, _: &Self::AdjMatrix, a: NodeIndex<Ix>, b: NodeIndex<Ix>, ) -> bool

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

impl<N, E, Ty: EdgeType, Null: Nullable<Wrapped = E>, Ix: IndexType> GraphBase for MatrixGraph<N, E, Ty, Null, Ix>

type NodeId = NodeIndex<Ix>

node identifier

type EdgeId = (NodeIndex<Ix>, NodeIndex<Ix>)

edge identifier

impl<N, E, Ty: EdgeType, Null: Nullable<Wrapped = E>, Ix: IndexType> GraphProp for MatrixGraph<N, E, Ty, Null, Ix>

type EdgeType = Ty

The kind of edges in the graph.

fn is_directed(&self) -> bool

impl<N, E, Ty: EdgeType, Null: Nullable<Wrapped = E>, Ix: IndexType> Index<(NodeIndex<Ix>, NodeIndex<Ix>)> for MatrixGraph<N, E, Ty, Null, Ix>

Index the MatrixGraph by NodeIndex pair to access edge weights.

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

Panics if no edge exists between a and b.

type Output = E

The returned type after indexing.

fn index(&self, (ax, bx): (NodeIndex<Ix>, NodeIndex<Ix>)) -> &E

Performs the indexing (container[index]) operation.

impl<N, E, Ty: EdgeType, Null: Nullable<Wrapped = E>, Ix: IndexType> Index<NodeIndex<Ix>> for MatrixGraph<N, E, Ty, Null, Ix>

Index the MatrixGraph by NodeIndex to access node weights.

Panics if the node doesn’t exist.

type Output = N

The returned type after indexing.

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

Performs the indexing (container[index]) operation.

impl<N, E, Ty: EdgeType, Null: Nullable<Wrapped = E>, Ix: IndexType> IndexMut<(NodeIndex<Ix>, NodeIndex<Ix>)> for MatrixGraph<N, E, Ty, Null, Ix>

Index the MatrixGraph by NodeIndex pair to access edge weights.

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

Panics if no edge exists between a and b.

fn index_mut(&mut self, (ax, bx): (NodeIndex<Ix>, NodeIndex<Ix>)) -> &mut E

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

impl<N, E, Ty: EdgeType, Null: Nullable<Wrapped = E>, Ix: IndexType> IndexMut<NodeIndex<Ix>> for MatrixGraph<N, E, Ty, Null, Ix>

Index the MatrixGraph by NodeIndex to access node weights.

Panics if the node doesn’t exist.

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

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

impl<'a, N, E, Ty: EdgeType, Null: Nullable<Wrapped = E>, Ix: IndexType> IntoEdgeReferences for &'a MatrixGraph<N, E, Ty, Null, Ix>

type EdgeRef = (NodeIndex<Ix>, NodeIndex<Ix>, &'a E)

type EdgeReferences = EdgeReferences<'a, Ty, Null, Ix>

fn edge_references(self) -> Self::EdgeReferences

impl<'a, N, E, Ty: EdgeType, Null: Nullable<Wrapped = E>, Ix: IndexType> IntoEdges for &'a MatrixGraph<N, E, Ty, Null, Ix>

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

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

impl<'a, N, E, Null: Nullable<Wrapped = E>, Ix: IndexType> IntoEdgesDirected for &'a MatrixGraph<N, E, Directed, Null, Ix>

type EdgesDirected = Edges<'a, Directed, Null, Ix>

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

impl<'a, N, E: 'a, Ty: EdgeType, Null: Nullable<Wrapped = E>, Ix: IndexType> IntoNeighbors for &'a MatrixGraph<N, E, Ty, Null, Ix>

type Neighbors = Neighbors<'a, Ty, Null, Ix>

fn neighbors(self, a: NodeIndex<Ix>) -> Self::Neighbors

Return an iterator of the neighbors of node a.

impl<'a, N, E: 'a, Null: Nullable<Wrapped = E>, Ix: IndexType> IntoNeighborsDirected for &'a MatrixGraph<N, E, Directed, Null, Ix>

type NeighborsDirected = Neighbors<'a, Directed, Null, Ix>

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

impl<'a, N, E: 'a, Ty: EdgeType, Null: Nullable<Wrapped = E>, Ix: IndexType> IntoNodeIdentifiers for &'a MatrixGraph<N, E, Ty, Null, Ix>

type NodeIdentifiers = NodeIdentifiers<'a, Ix>

fn node_identifiers(self) -> Self::NodeIdentifiers

impl<'a, N, E, Ty: EdgeType, Null: Nullable<Wrapped = E>, Ix: IndexType> IntoNodeReferences for &'a MatrixGraph<N, E, Ty, Null, Ix>

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

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

fn node_references(self) -> Self::NodeReferences

impl<N, E, Ty: EdgeType, Null: Nullable<Wrapped = E>, Ix: IndexType> NodeCount for MatrixGraph<N, E, Ty, Null, Ix>

fn node_count(&self) -> usize

impl<N, E, Ty: EdgeType, Null: Nullable<Wrapped = E>, Ix: IndexType> NodeIndexable for MatrixGraph<N, E, Ty, Null, Ix>

fn node_bound(&self) -> usize

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

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: EdgeType, Null: Nullable<Wrapped = E>, Ix: IndexType> Visitable for MatrixGraph<N, E, Ty, Null, Ix>

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)