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+//! `MatrixGraph<N, E, Ty, NullN, NullE, Ix>` is a graph datastructure backed by an adjacency matrix.
+
+use std::marker::PhantomData;
+use std::ops::{Index, IndexMut};
+
+use std::cmp;
+use std::mem;
+
+use indexmap::IndexSet;
+
+use fixedbitset::FixedBitSet;
+
+use crate::{Directed, Direction, EdgeType, IntoWeightedEdge, Outgoing, Undirected};
+
+use crate::graph::NodeIndex as GraphNodeIndex;
+
+use crate::visit::{
+ Data, EdgeCount, GetAdjacencyMatrix, GraphBase, GraphProp, IntoEdgeReferences, IntoEdges,
+ IntoEdgesDirected, IntoNeighbors, IntoNeighborsDirected, IntoNodeIdentifiers,
+ IntoNodeReferences, NodeCount, NodeIndexable, Visitable,
+};
+
+use crate::data::Build;
+
+pub use crate::graph::IndexType;
+
+// The following types are used to control the max size of the adjacency matrix. Since the maximum
+// size of the matrix vector's is the square of the maximum number of nodes, the number of nodes
+// should be reasonably picked.
+type DefaultIx = u16;
+
+/// Node identifier.
+pub type NodeIndex<Ix = DefaultIx> = GraphNodeIndex<Ix>;
+
+mod private {
+ pub trait Sealed {}
+
+ impl<T> Sealed for super::NotZero<T> {}
+ impl<T> Sealed for Option<T> {}
+}
+
+/// Wrapper trait for an `Option`, allowing user-defined structs to be input as containers when
+/// defining a null element.
+///
+/// Note: this trait is currently *sealed* and cannot be implemented for types outside this crate.
+pub trait Nullable: Default + Into<Option<<Self as Nullable>::Wrapped>> + private::Sealed {
+ #[doc(hidden)]
+ type Wrapped;
+
+ #[doc(hidden)]
+ fn new(value: Self::Wrapped) -> Self;
+
+ #[doc(hidden)]
+ fn as_ref(&self) -> Option<&Self::Wrapped>;
+
+ #[doc(hidden)]
+ fn as_mut(&mut self) -> Option<&mut Self::Wrapped>;
+
+ #[doc(hidden)]
+ fn is_null(&self) -> bool {
+ self.as_ref().is_none()
+ }
+}
+
+impl<T> Nullable for Option<T> {
+ type Wrapped = T;
+
+ fn new(value: T) -> Self {
+ Some(value)
+ }
+
+ fn as_ref(&self) -> Option<&Self::Wrapped> {
+ self.as_ref()
+ }
+
+ fn as_mut(&mut self) -> Option<&mut Self::Wrapped> {
+ self.as_mut()
+ }
+}
+
+/// `NotZero` is used to optimize the memory usage of edge weights `E` in a
+/// [`MatrixGraph`](struct.MatrixGraph.html), replacing the default `Option<E>` sentinel.
+///
+/// Pre-requisite: edge weight should implement [`Zero`](trait.Zero.html).
+///
+/// Note that if you're already using the standard non-zero types (such as `NonZeroU32`), you don't
+/// have to use this wrapper and can leave the default `Null` type argument.
+pub struct NotZero<T>(T);
+
+impl<T: Zero> Default for NotZero<T> {
+ fn default() -> Self {
+ NotZero(T::zero())
+ }
+}
+
+impl<T: Zero> Nullable for NotZero<T> {
+ #[doc(hidden)]
+ type Wrapped = T;
+
+ #[doc(hidden)]
+ fn new(value: T) -> Self {
+ assert!(!value.is_zero());
+ NotZero(value)
+ }
+
+ // implemented here for optimization purposes
+ #[doc(hidden)]
+ fn is_null(&self) -> bool {
+ self.0.is_zero()
+ }
+
+ #[doc(hidden)]
+ fn as_ref(&self) -> Option<&Self::Wrapped> {
+ if !self.is_null() {
+ Some(&self.0)
+ } else {
+ None
+ }
+ }
+
+ #[doc(hidden)]
+ fn as_mut(&mut self) -> Option<&mut Self::Wrapped> {
+ if !self.is_null() {
+ Some(&mut self.0)
+ } else {
+ None
+ }
+ }
+}
+
+impl<T: Zero> From<NotZero<T>> for Option<T> {
+ fn from(not_zero: NotZero<T>) -> Self {
+ if !not_zero.is_null() {
+ Some(not_zero.0)
+ } else {
+ None
+ }
+ }
+}
+
+/// Base trait for types that can be wrapped in a [`NotZero`](struct.NotZero.html).
+///
+/// Implementors must provide a singleton object that will be used to mark empty edges in a
+/// [`MatrixGraph`](struct.MatrixGraph.html).
+///
+/// Note that this trait is already implemented for the base numeric types.
+pub trait Zero {
+ /// Return the singleton object which can be used as a sentinel value.
+ fn zero() -> Self;
+
+ /// Return true if `self` is equal to the sentinel value.
+ fn is_zero(&self) -> bool;
+}
+
+macro_rules! not_zero_impl {
+ ($t:ty,$z:expr) => {
+ impl Zero for $t {
+ fn zero() -> Self {
+ $z as $t
+ }
+
+ #[allow(clippy::float_cmp)]
+ fn is_zero(&self) -> bool {
+ self == &Self::zero()
+ }
+ }
+ };
+}
+
+macro_rules! not_zero_impls {
+ ($($t:ty),*) => {
+ $(
+ not_zero_impl!($t, 0);
+ )*
+ }
+}
+
+not_zero_impls!(u8, u16, u32, u64, usize);
+not_zero_impls!(i8, i16, i32, i64, isize);
+not_zero_impls!(f32, f64);
+
+/// Short version of `NodeIndex::new` (with Ix = `DefaultIx`)
+#[inline]
+pub fn node_index(ax: usize) -> NodeIndex {
+ NodeIndex::new(ax)
+}
+
+/// `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>`](struct.NotZero.html) 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.
+#[derive(Clone)]
+pub struct MatrixGraph<N, E, Ty = Directed, Null: Nullable<Wrapped = E> = Option<E>, Ix = DefaultIx>
+{
+ node_adjacencies: Vec<Null>,
+ node_capacity: usize,
+ nodes: IdStorage<N>,
+ nb_edges: usize,
+ ty: PhantomData<Ty>,
+ ix: PhantomData<Ix>,
+}
+
+/// A `MatrixGraph` with directed edges.
+pub type DiMatrix<N, E, Null = Option<E>, Ix = DefaultIx> = MatrixGraph<N, E, Directed, Null, Ix>;
+
+/// A `MatrixGraph` with undirected edges.
+pub type UnMatrix<N, E, Null = Option<E>, Ix = DefaultIx> = MatrixGraph<N, E, Undirected, Null, Ix>;
+
+impl<N, E, Ty: EdgeType, Null: Nullable<Wrapped = E>, Ix: IndexType>
+ MatrixGraph<N, E, Ty, Null, Ix>
+{
+ /// Create a new `MatrixGraph` with estimated capacity for nodes.
+ pub fn with_capacity(node_capacity: usize) -> Self {
+ let mut m = Self {
+ node_adjacencies: vec![],
+ node_capacity: 0,
+ nodes: IdStorage::with_capacity(node_capacity),
+ nb_edges: 0,
+ ty: PhantomData,
+ ix: PhantomData,
+ };
+
+ debug_assert!(node_capacity <= <Ix as IndexType>::max().index());
+ if node_capacity > 0 {
+ m.extend_capacity_for_node(NodeIndex::new(node_capacity - 1), true);
+ }
+
+ m
+ }
+
+ #[inline]
+ fn to_edge_position(&self, a: NodeIndex<Ix>, b: NodeIndex<Ix>) -> Option<usize> {
+ if cmp::max(a.index(), b.index()) >= self.node_capacity {
+ return None;
+ }
+ Some(self.to_edge_position_unchecked(a, b))
+ }
+
+ #[inline]
+ fn to_edge_position_unchecked(&self, a: NodeIndex<Ix>, b: NodeIndex<Ix>) -> usize {
+ to_linearized_matrix_position::<Ty>(a.index(), b.index(), self.node_capacity)
+ }
+
+ /// Remove all nodes and edges.
+ pub fn clear(&mut self) {
+ for edge in self.node_adjacencies.iter_mut() {
+ *edge = Default::default();
+ }
+ self.nodes.clear();
+ self.nb_edges = 0;
+ }
+
+ /// Return the number of nodes (vertices) in the graph.
+ ///
+ /// Computes in **O(1)** time.
+ #[inline]
+ pub fn node_count(&self) -> usize {
+ self.nodes.len()
+ }
+
+ /// Return the number of edges in the graph.
+ ///
+ /// Computes in **O(1)** time.
+ #[inline]
+ pub fn edge_count(&self) -> usize {
+ self.nb_edges
+ }
+
+ /// Return whether the graph has directed edges or not.
+ #[inline]
+ pub fn is_directed(&self) -> bool {
+ Ty::is_directed()
+ }
+
+ /// 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 add_node(&mut self, weight: N) -> NodeIndex<Ix> {
+ NodeIndex::new(self.nodes.add(weight))
+ }
+
+ /// 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 remove_node(&mut self, a: NodeIndex<Ix>) -> N {
+ for id in self.nodes.iter_ids() {
+ let position = self.to_edge_position(a, NodeIndex::new(id));
+ if let Some(pos) = position {
+ self.node_adjacencies[pos] = Default::default();
+ }
+
+ if Ty::is_directed() {
+ let position = self.to_edge_position(NodeIndex::new(id), a);
+ if let Some(pos) = position {
+ self.node_adjacencies[pos] = Default::default();
+ }
+ }
+ }
+
+ self.nodes.remove(a.index())
+ }
+
+ #[inline]
+ fn extend_capacity_for_node(&mut self, min_node: NodeIndex<Ix>, exact: bool) {
+ self.node_capacity = extend_linearized_matrix::<Ty, _>(
+ &mut self.node_adjacencies,
+ self.node_capacity,
+ min_node.index() + 1,
+ exact,
+ );
+ }
+
+ #[inline]
+ fn extend_capacity_for_edge(&mut self, a: NodeIndex<Ix>, b: NodeIndex<Ix>) {
+ let min_node = cmp::max(a, b);
+ if min_node.index() >= self.node_capacity {
+ self.extend_capacity_for_node(min_node, false);
+ }
+ }
+
+ /// 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 update_edge(&mut self, a: NodeIndex<Ix>, b: NodeIndex<Ix>, weight: E) -> Option<E> {
+ self.extend_capacity_for_edge(a, b);
+ let p = self.to_edge_position_unchecked(a, b);
+ let old_weight = mem::replace(&mut self.node_adjacencies[p], Null::new(weight));
+ if old_weight.is_null() {
+ self.nb_edges += 1;
+ }
+ old_weight.into()
+ }
+
+ /// 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)`](#method.update_edge) instead.
+ pub fn add_edge(&mut self, a: NodeIndex<Ix>, b: NodeIndex<Ix>, weight: E) {
+ let old_edge_id = self.update_edge(a, b, weight);
+ assert!(old_edge_id.is_none());
+ }
+
+ /// 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 remove_edge(&mut self, a: NodeIndex<Ix>, b: NodeIndex<Ix>) -> E {
+ let p = self
+ .to_edge_position(a, b)
+ .expect("No edge found between the nodes.");
+ let old_weight = mem::take(&mut self.node_adjacencies[p]).into().unwrap();
+ let old_weight: Option<_> = old_weight.into();
+ self.nb_edges -= 1;
+ old_weight.unwrap()
+ }
+
+ /// Return true if there is an edge between `a` and `b`.
+ ///
+ /// **Panics** if any of the nodes don't exist.
+ pub fn has_edge(&self, a: NodeIndex<Ix>, b: NodeIndex<Ix>) -> bool {
+ if let Some(p) = self.to_edge_position(a, b) {
+ return !self.node_adjacencies[p].is_null();
+ }
+ false
+ }
+
+ /// Access the weight for node `a`.
+ ///
+ /// Also available with indexing syntax: `&graph[a]`.
+ ///
+ /// **Panics** if the node doesn't exist.
+ pub fn node_weight(&self, a: NodeIndex<Ix>) -> &N {
+ &self.nodes[a.index()]
+ }
+
+ /// Access the weight for node `a`, mutably.
+ ///
+ /// Also available with indexing syntax: `&mut graph[a]`.
+ ///
+ /// **Panics** if the node doesn't exist.
+ pub fn node_weight_mut(&mut self, a: NodeIndex<Ix>) -> &mut N {
+ &mut self.nodes[a.index()]
+ }
+
+ /// 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(&self, a: NodeIndex<Ix>, b: NodeIndex<Ix>) -> &E {
+ let p = self
+ .to_edge_position(a, b)
+ .expect("No edge found between the nodes.");
+ self.node_adjacencies[p]
+ .as_ref()
+ .expect("No edge found between the nodes.")
+ }
+
+ /// 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 edge_weight_mut(&mut self, a: NodeIndex<Ix>, b: NodeIndex<Ix>) -> &mut E {
+ let p = self
+ .to_edge_position(a, b)
+ .expect("No edge found between the nodes.");
+ self.node_adjacencies[p]
+ .as_mut()
+ .expect("No edge found between the nodes.")
+ }
+
+ /// 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.<br>
+ /// Iterator element type is [`NodeIndex<Ix>`](../graph/struct.NodeIndex.html).
+ pub fn neighbors(&self, a: NodeIndex<Ix>) -> Neighbors<Ty, Null, Ix> {
+ Neighbors(Edges::on_columns(
+ a.index(),
+ &self.node_adjacencies,
+ self.node_capacity,
+ ))
+ }
+
+ /// 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.<br>
+ /// Iterator element type is `(NodeIndex<Ix>, NodeIndex<Ix>, &E)`.
+ pub fn edges(&self, a: NodeIndex<Ix>) -> Edges<Ty, Null, Ix> {
+ Edges::on_columns(a.index(), &self.node_adjacencies, self.node_capacity)
+ }
+
+ /// 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 from_edges<I>(iterable: I) -> Self
+ where
+ I: IntoIterator,
+ I::Item: IntoWeightedEdge<E>,
+ <I::Item as IntoWeightedEdge<E>>::NodeId: Into<NodeIndex<Ix>>,
+ N: Default,
+ {
+ let mut g = Self::default();
+ g.extend_with_edges(iterable);
+ g
+ }
+
+ /// 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.
+ 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,
+ {
+ for elt in iterable {
+ let (source, target, weight) = elt.into_weighted_edge();
+ let (source, target) = (source.into(), target.into());
+ let nx = cmp::max(source, target);
+ while nx.index() >= self.node_count() {
+ self.add_node(N::default());
+ }
+ self.add_edge(source, target, weight);
+ }
+ }
+}
+
+impl<N, E, Null: Nullable<Wrapped = E>, Ix: IndexType> MatrixGraph<N, E, 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.<br>
+ /// Iterator element type is [`NodeIndex<Ix>`](../graph/struct.NodeIndex.html).
+ pub fn neighbors_directed(
+ &self,
+ a: NodeIndex<Ix>,
+ d: Direction,
+ ) -> Neighbors<Directed, Null, Ix> {
+ if d == Outgoing {
+ self.neighbors(a)
+ } else {
+ Neighbors(Edges::on_rows(
+ a.index(),
+ &self.node_adjacencies,
+ self.node_capacity,
+ ))
+ }
+ }
+
+ /// 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.<br>
+ /// Iterator element type is `(NodeIndex<Ix>, NodeIndex<Ix>, &E)`.
+ pub fn edges_directed(&self, a: NodeIndex<Ix>, d: Direction) -> Edges<Directed, Null, Ix> {
+ if d == Outgoing {
+ self.edges(a)
+ } else {
+ Edges::on_rows(a.index(), &self.node_adjacencies, self.node_capacity)
+ }
+ }
+}
+
+/// Iterator over the node identifiers of a graph.
+///
+/// Created from a call to [`.node_identifiers()`][1] on a [`MatrixGraph`][2].
+///
+/// [1]: ../visit/trait.IntoNodeIdentifiers.html#tymethod.node_identifiers
+/// [2]: struct.MatrixGraph.html
+#[derive(Debug, Clone)]
+pub struct NodeIdentifiers<'a, Ix> {
+ iter: IdIterator<'a>,
+ ix: PhantomData<Ix>,
+}
+
+impl<'a, Ix: IndexType> NodeIdentifiers<'a, Ix> {
+ fn new(iter: IdIterator<'a>) -> Self {
+ Self {
+ iter,
+ ix: PhantomData,
+ }
+ }
+}
+
+impl<Ix: IndexType> Iterator for NodeIdentifiers<'_, Ix> {
+ type Item = NodeIndex<Ix>;
+
+ fn next(&mut self) -> Option<Self::Item> {
+ self.iter.next().map(NodeIndex::new)
+ }
+ fn size_hint(&self) -> (usize, Option<usize>) {
+ self.iter.size_hint()
+ }
+}
+
+/// Iterator over all nodes of a graph.
+///
+/// Created from a call to [`.node_references()`][1] on a [`MatrixGraph`][2].
+///
+/// [1]: ../visit/trait.IntoNodeReferences.html#tymethod.node_references
+/// [2]: struct.MatrixGraph.html
+#[derive(Debug, Clone)]
+pub struct NodeReferences<'a, N: 'a, Ix> {
+ nodes: &'a IdStorage<N>,
+ iter: IdIterator<'a>,
+ ix: PhantomData<Ix>,
+}
+
+impl<'a, N: 'a, Ix> NodeReferences<'a, N, Ix> {
+ fn new(nodes: &'a IdStorage<N>) -> Self {
+ NodeReferences {
+ nodes,
+ iter: nodes.iter_ids(),
+ ix: PhantomData,
+ }
+ }
+}
+
+impl<'a, N: 'a, Ix: IndexType> Iterator for NodeReferences<'a, N, Ix> {
+ type Item = (NodeIndex<Ix>, &'a N);
+
+ fn next(&mut self) -> Option<Self::Item> {
+ self.iter
+ .next()
+ .map(|i| (NodeIndex::new(i), &self.nodes[i]))
+ }
+ fn size_hint(&self) -> (usize, Option<usize>) {
+ self.iter.size_hint()
+ }
+}
+
+/// Iterator over all edges of a graph.
+///
+/// Created from a call to [`.edge_references()`][1] on a [`MatrixGraph`][2].
+///
+/// [1]: ../visit/trait.IntoEdgeReferences.html#tymethod.edge_references
+/// [2]: struct.MatrixGraph.html
+#[derive(Debug, Clone)]
+pub struct EdgeReferences<'a, Ty: EdgeType, Null: 'a + Nullable, Ix> {
+ row: usize,
+ column: usize,
+ node_adjacencies: &'a [Null],
+ node_capacity: usize,
+ ty: PhantomData<Ty>,
+ ix: PhantomData<Ix>,
+}
+
+impl<'a, Ty: EdgeType, Null: 'a + Nullable, Ix> EdgeReferences<'a, Ty, Null, Ix> {
+ fn new(node_adjacencies: &'a [Null], node_capacity: usize) -> Self {
+ EdgeReferences {
+ row: 0,
+ column: 0,
+ node_adjacencies,
+ node_capacity,
+ ty: PhantomData,
+ ix: PhantomData,
+ }
+ }
+}
+
+impl<'a, Ty: EdgeType, Null: Nullable, Ix: IndexType> Iterator
+ for EdgeReferences<'a, Ty, Null, Ix>
+{
+ type Item = (NodeIndex<Ix>, NodeIndex<Ix>, &'a Null::Wrapped);
+
+ fn next(&mut self) -> Option<Self::Item> {
+ loop {
+ let (row, column) = (self.row, self.column);
+ if row >= self.node_capacity {
+ return None;
+ }
+
+ // By default, advance the column. Reset and advance the row if the column overflows.
+ //
+ // Note that for undirected graphs, we don't want to yield the same edge twice,
+ // therefore the maximum column length should be the index new after the row index.
+ self.column += 1;
+ let max_column_len = if !Ty::is_directed() {
+ row + 1
+ } else {
+ self.node_capacity
+ };
+ if self.column >= max_column_len {
+ self.column = 0;
+ self.row += 1;
+ }
+
+ let p = to_linearized_matrix_position::<Ty>(row, column, self.node_capacity);
+ if let Some(e) = self.node_adjacencies[p].as_ref() {
+ return Some((NodeIndex::new(row), NodeIndex::new(column), e));
+ }
+ }
+ }
+}
+
+/// Iterator over the neighbors of a node.
+///
+/// Iterator element type is `NodeIndex<Ix>`.
+///
+/// Created with [`.neighbors()`][1], [`.neighbors_directed()`][2].
+///
+/// [1]: struct.MatrixGraph.html#method.neighbors
+/// [2]: struct.MatrixGraph.html#method.neighbors_directed
+#[derive(Debug, Clone)]
+pub struct Neighbors<'a, Ty: EdgeType, Null: 'a + Nullable, Ix>(Edges<'a, Ty, Null, Ix>);
+
+impl<Ty: EdgeType, Null: Nullable, Ix: IndexType> Iterator for Neighbors<'_, Ty, Null, Ix> {
+ type Item = NodeIndex<Ix>;
+
+ fn next(&mut self) -> Option<Self::Item> {
+ self.0.next().map(|(_, b, _)| b)
+ }
+ fn size_hint(&self) -> (usize, Option<usize>) {
+ self.0.size_hint()
+ }
+}
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+enum NeighborIterDirection {
+ Rows,
+ Columns,
+}
+
+/// Iterator over the edges of from or to a node
+///
+/// Created with [`.edges()`][1], [`.edges_directed()`][2].
+///
+/// [1]: struct.MatrixGraph.html#method.edges
+/// [2]: struct.MatrixGraph.html#method.edges_directed
+#[derive(Debug, Clone)]
+pub struct Edges<'a, Ty: EdgeType, Null: 'a + Nullable, Ix> {
+ iter_direction: NeighborIterDirection,
+ node_adjacencies: &'a [Null],
+ node_capacity: usize,
+ row: usize,
+ column: usize,
+ ty: PhantomData<Ty>,
+ ix: PhantomData<Ix>,
+}
+
+impl<'a, Ty: EdgeType, Null: 'a + Nullable, Ix> Edges<'a, Ty, Null, Ix> {
+ fn on_columns(row: usize, node_adjacencies: &'a [Null], node_capacity: usize) -> Self {
+ Edges {
+ iter_direction: NeighborIterDirection::Columns,
+ node_adjacencies,
+ node_capacity,
+ row,
+ column: 0,
+ ty: PhantomData,
+ ix: PhantomData,
+ }
+ }
+
+ fn on_rows(column: usize, node_adjacencies: &'a [Null], node_capacity: usize) -> Self {
+ Edges {
+ iter_direction: NeighborIterDirection::Rows,
+ node_adjacencies,
+ node_capacity,
+ row: 0,
+ column,
+ ty: PhantomData,
+ ix: PhantomData,
+ }
+ }
+}
+
+impl<'a, Ty: EdgeType, Null: Nullable, Ix: IndexType> Iterator for Edges<'a, Ty, Null, Ix> {
+ type Item = (NodeIndex<Ix>, NodeIndex<Ix>, &'a Null::Wrapped);
+
+ fn next(&mut self) -> Option<Self::Item> {
+ use self::NeighborIterDirection::*;
+
+ loop {
+ let (row, column) = (self.row, self.column);
+ if row >= self.node_capacity || column >= self.node_capacity {
+ return None;
+ }
+
+ match self.iter_direction {
+ Rows => self.row += 1,
+ Columns => self.column += 1,
+ }
+
+ let p = to_linearized_matrix_position::<Ty>(row, column, self.node_capacity);
+ if let Some(e) = self.node_adjacencies[p].as_ref() {
+ let (a, b) = match self.iter_direction {
+ Rows => (column, row),
+ Columns => (row, column),
+ };
+
+ return Some((NodeIndex::new(a), NodeIndex::new(b), e));
+ }
+ }
+ }
+}
+
+#[inline]
+fn to_linearized_matrix_position<Ty: EdgeType>(row: usize, column: usize, width: usize) -> usize {
+ if Ty::is_directed() {
+ to_flat_square_matrix_position(row, column, width)
+ } else {
+ to_lower_triangular_matrix_position(row, column)
+ }
+}
+
+#[inline]
+fn extend_linearized_matrix<Ty: EdgeType, T: Default>(
+ node_adjacencies: &mut Vec<T>,
+ old_node_capacity: usize,
+ new_capacity: usize,
+ exact: bool,
+) -> usize {
+ if old_node_capacity >= new_capacity {
+ return old_node_capacity;
+ }
+ if Ty::is_directed() {
+ extend_flat_square_matrix(node_adjacencies, old_node_capacity, new_capacity, exact)
+ } else {
+ extend_lower_triangular_matrix(node_adjacencies, new_capacity)
+ }
+}
+
+#[inline]
+fn to_flat_square_matrix_position(row: usize, column: usize, width: usize) -> usize {
+ row * width + column
+}
+
+#[inline]
+fn extend_flat_square_matrix<T: Default>(
+ node_adjacencies: &mut Vec<T>,
+ old_node_capacity: usize,
+ new_node_capacity: usize,
+ exact: bool,
+) -> usize {
+ // Grow the capacity by exponential steps to avoid repeated allocations.
+ // Disabled for the with_capacity constructor.
+ let new_node_capacity = if exact {
+ new_node_capacity
+ } else {
+ const MIN_CAPACITY: usize = 4;
+ cmp::max(new_node_capacity.next_power_of_two(), MIN_CAPACITY)
+ };
+
+ // Optimization: when resizing the matrix this way we skip the first few grows to make
+ // small matrices a bit faster to work with.
+
+ ensure_len(node_adjacencies, new_node_capacity.pow(2));
+ for c in (1..old_node_capacity).rev() {
+ let pos = c * old_node_capacity;
+ let new_pos = c * new_node_capacity;
+ // Move the slices directly if they do not overlap with their new position
+ if pos + old_node_capacity <= new_pos {
+ debug_assert!(pos + old_node_capacity < node_adjacencies.len());
+ debug_assert!(new_pos + old_node_capacity < node_adjacencies.len());
+ let ptr = node_adjacencies.as_mut_ptr();
+ // SAFETY: pos + old_node_capacity <= new_pos, so this won't overlap
+ unsafe {
+ let old = ptr.add(pos);
+ let new = ptr.add(new_pos);
+ core::ptr::swap_nonoverlapping(old, new, old_node_capacity);
+ }
+ } else {
+ for i in (0..old_node_capacity).rev() {
+ node_adjacencies.as_mut_slice().swap(pos + i, new_pos + i);
+ }
+ }
+ }
+
+ new_node_capacity
+}
+
+#[inline]
+fn to_lower_triangular_matrix_position(row: usize, column: usize) -> usize {
+ let (row, column) = if row > column {
+ (row, column)
+ } else {
+ (column, row)
+ };
+ (row * (row + 1)) / 2 + column
+}
+
+#[inline]
+fn extend_lower_triangular_matrix<T: Default>(
+ node_adjacencies: &mut Vec<T>,
+ new_capacity: usize,
+) -> usize {
+ let max_node = new_capacity - 1;
+ let max_pos = to_lower_triangular_matrix_position(max_node, max_node);
+ ensure_len(node_adjacencies, max_pos + 1);
+ new_capacity
+}
+
+/// Grow a Vec by appending the type's default value until the `size` is reached.
+fn ensure_len<T: Default>(v: &mut Vec<T>, size: usize) {
+ v.resize_with(size, T::default);
+}
+
+#[derive(Debug, Clone)]
+struct IdStorage<T> {
+ elements: Vec<Option<T>>,
+ upper_bound: usize,
+ removed_ids: IndexSet<usize>,
+}
+
+impl<T> IdStorage<T> {
+ fn with_capacity(capacity: usize) -> Self {
+ IdStorage {
+ elements: Vec::with_capacity(capacity),
+ upper_bound: 0,
+ removed_ids: IndexSet::new(),
+ }
+ }
+
+ fn add(&mut self, element: T) -> usize {
+ let id = if let Some(id) = self.removed_ids.pop() {
+ id
+ } else {
+ let id = self.upper_bound;
+ self.upper_bound += 1;
+
+ ensure_len(&mut self.elements, id + 1);
+
+ id
+ };
+
+ self.elements[id] = Some(element);
+
+ id
+ }
+
+ fn remove(&mut self, id: usize) -> T {
+ let data = self.elements[id].take().unwrap();
+ if self.upper_bound - id == 1 {
+ self.upper_bound -= 1;
+ } else {
+ self.removed_ids.insert(id);
+ }
+ data
+ }
+
+ fn clear(&mut self) {
+ self.upper_bound = 0;
+ self.elements.clear();
+ self.removed_ids.clear();
+ }
+
+ #[inline]
+ fn len(&self) -> usize {
+ self.upper_bound - self.removed_ids.len()
+ }
+
+ fn iter_ids(&self) -> IdIterator {
+ IdIterator {
+ upper_bound: self.upper_bound,
+ removed_ids: &self.removed_ids,
+ current: None,
+ }
+ }
+}
+
+impl<T> Index<usize> for IdStorage<T> {
+ type Output = T;
+ fn index(&self, index: usize) -> &T {
+ self.elements[index].as_ref().unwrap()
+ }
+}
+
+impl<T> IndexMut<usize> for IdStorage<T> {
+ fn index_mut(&mut self, index: usize) -> &mut T {
+ self.elements[index].as_mut().unwrap()
+ }
+}
+
+#[derive(Debug, Clone)]
+struct IdIterator<'a> {
+ upper_bound: usize,
+ removed_ids: &'a IndexSet<usize>,
+ current: Option<usize>,
+}
+
+impl Iterator for IdIterator<'_> {
+ type Item = usize;
+
+ fn next(&mut self) -> Option<Self::Item> {
+ // initialize / advance
+ let current = {
+ if self.current.is_none() {
+ self.current = Some(0);
+ self.current.as_mut().unwrap()
+ } else {
+ let current = self.current.as_mut().unwrap();
+ *current += 1;
+ current
+ }
+ };
+
+ // skip removed ids
+ while self.removed_ids.contains(current) && *current < self.upper_bound {
+ *current += 1;
+ }
+
+ if *current < self.upper_bound {
+ Some(*current)
+ } else {
+ None
+ }
+ }
+}
+
+/// Create a new empty `MatrixGraph`.
+impl<N, E, Ty: EdgeType, Null: Nullable<Wrapped = E>, Ix: IndexType> Default
+ for MatrixGraph<N, E, Ty, Null, Ix>
+{
+ fn default() -> Self {
+ Self::with_capacity(0)
+ }
+}
+
+impl<N, E> MatrixGraph<N, E, Directed> {
+ /// 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`.
+ pub fn new() -> Self {
+ MatrixGraph::default()
+ }
+}
+
+impl<N, E> MatrixGraph<N, E, Undirected> {
+ /// 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`.
+ pub fn new_undirected() -> Self {
+ MatrixGraph::default()
+ }
+}
+
+/// Index the `MatrixGraph` by `NodeIndex` to access node weights.
+///
+/// **Panics** if the node doesn't exist.
+impl<N, E, Ty: EdgeType, Null: Nullable<Wrapped = E>, Ix: IndexType> Index<NodeIndex<Ix>>
+ for MatrixGraph<N, E, Ty, Null, Ix>
+{
+ type Output = N;
+
+ fn index(&self, ax: NodeIndex<Ix>) -> &N {
+ self.node_weight(ax)
+ }
+}
+
+/// Index the `MatrixGraph` by `NodeIndex` to access node weights.
+///
+/// **Panics** if the node doesn't exist.
+impl<N, E, Ty: EdgeType, Null: Nullable<Wrapped = E>, Ix: IndexType> IndexMut<NodeIndex<Ix>>
+ for MatrixGraph<N, E, Ty, Null, Ix>
+{
+ fn index_mut(&mut self, ax: NodeIndex<Ix>) -> &mut N {
+ self.node_weight_mut(ax)
+ }
+}
+
+impl<N, E, Ty: EdgeType, Null: Nullable<Wrapped = E>, Ix: IndexType> NodeCount
+ for MatrixGraph<N, E, Ty, Null, Ix>
+{
+ fn node_count(&self) -> usize {
+ MatrixGraph::node_count(self)
+ }
+}
+
+impl<N, E, Ty: EdgeType, Null: Nullable<Wrapped = E>, Ix: IndexType> EdgeCount
+ for MatrixGraph<N, E, Ty, Null, Ix>
+{
+ #[inline]
+ fn edge_count(&self) -> usize {
+ self.edge_count()
+ }
+}
+
+/// 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`.
+impl<N, E, Ty: EdgeType, Null: Nullable<Wrapped = E>, Ix: IndexType>
+ Index<(NodeIndex<Ix>, NodeIndex<Ix>)> for MatrixGraph<N, E, Ty, Null, Ix>
+{
+ type Output = E;
+
+ fn index(&self, (ax, bx): (NodeIndex<Ix>, NodeIndex<Ix>)) -> &E {
+ self.edge_weight(ax, bx)
+ }
+}
+
+/// 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`.
+impl<N, E, Ty: EdgeType, Null: Nullable<Wrapped = E>, Ix: IndexType>
+ IndexMut<(NodeIndex<Ix>, NodeIndex<Ix>)> for MatrixGraph<N, E, Ty, Null, Ix>
+{
+ fn index_mut(&mut self, (ax, bx): (NodeIndex<Ix>, NodeIndex<Ix>)) -> &mut E {
+ self.edge_weight_mut(ax, bx)
+ }
+}
+
+impl<N, E, Ty: EdgeType, Null: Nullable<Wrapped = E>, Ix: IndexType> GetAdjacencyMatrix
+ for MatrixGraph<N, E, Ty, Null, Ix>
+{
+ type AdjMatrix = ();
+
+ fn adjacency_matrix(&self) -> Self::AdjMatrix {}
+
+ fn is_adjacent(&self, _: &Self::AdjMatrix, a: NodeIndex<Ix>, b: NodeIndex<Ix>) -> bool {
+ MatrixGraph::has_edge(self, a, b)
+ }
+}
+
+impl<N, E, Ty: EdgeType, Null: Nullable<Wrapped = E>, Ix: IndexType> Visitable
+ for MatrixGraph<N, E, Ty, Null, Ix>
+{
+ type Map = FixedBitSet;
+
+ fn visit_map(&self) -> FixedBitSet {
+ FixedBitSet::with_capacity(self.node_bound())
+ }
+
+ fn reset_map(&self, map: &mut Self::Map) {
+ map.clear();
+ map.grow(self.node_bound());
+ }
+}
+
+impl<N, E, Ty: EdgeType, Null: Nullable<Wrapped = E>, Ix: IndexType> GraphBase
+ for MatrixGraph<N, E, Ty, Null, Ix>
+{
+ type NodeId = NodeIndex<Ix>;
+ type EdgeId = (NodeIndex<Ix>, NodeIndex<Ix>);
+}
+
+impl<N, E, Ty: EdgeType, Null: Nullable<Wrapped = E>, Ix: IndexType> GraphProp
+ for MatrixGraph<N, E, Ty, Null, Ix>
+{
+ type EdgeType = Ty;
+}
+
+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<'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 {
+ NodeIdentifiers::new(self.nodes.iter_ids())
+ }
+}
+
+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 {
+ MatrixGraph::neighbors(self, 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 {
+ MatrixGraph::neighbors_directed(self, a, d)
+ }
+}
+
+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 {
+ NodeReferences::new(&self.nodes)
+ }
+}
+
+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 {
+ EdgeReferences::new(&self.node_adjacencies, self.node_capacity)
+ }
+}
+
+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 {
+ MatrixGraph::edges(self, a)
+ }
+}
+
+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 {
+ MatrixGraph::edges_directed(self, a, dir)
+ }
+}
+
+impl<N, E, Ty: EdgeType, Null: Nullable<Wrapped = E>, Ix: IndexType> NodeIndexable
+ for MatrixGraph<N, E, Ty, Null, Ix>
+{
+ fn node_bound(&self) -> usize {
+ self.nodes.upper_bound
+ }
+
+ fn to_index(&self, ix: NodeIndex<Ix>) -> usize {
+ ix.index()
+ }
+
+ fn from_index(&self, ix: usize) -> Self::NodeId {
+ NodeIndex::new(ix)
+ }
+}
+
+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 {
+ self.add_node(weight)
+ }
+
+ fn add_edge(
+ &mut self,
+ a: Self::NodeId,
+ b: Self::NodeId,
+ weight: Self::EdgeWeight,
+ ) -> Option<Self::EdgeId> {
+ if !self.has_edge(a, b) {
+ MatrixGraph::update_edge(self, a, b, weight);
+ Some((a, b))
+ } else {
+ None
+ }
+ }
+
+ fn update_edge(
+ &mut self,
+ a: Self::NodeId,
+ b: Self::NodeId,
+ weight: Self::EdgeWeight,
+ ) -> Self::EdgeId {
+ MatrixGraph::update_edge(self, a, b, weight);
+ (a, b)
+ }
+}
+
+#[cfg(test)]
+mod tests {
+ use super::*;
+ use crate::{Incoming, Outgoing};
+
+ #[test]
+ fn test_new() {
+ let g = MatrixGraph::<i32, i32>::new();
+ assert_eq!(g.node_count(), 0);
+ assert_eq!(g.edge_count(), 0);
+ }
+
+ #[test]
+ fn test_default() {
+ let g = MatrixGraph::<i32, i32>::default();
+ assert_eq!(g.node_count(), 0);
+ assert_eq!(g.edge_count(), 0);
+ }
+
+ #[test]
+ fn test_with_capacity() {
+ let g = MatrixGraph::<i32, i32>::with_capacity(10);
+ assert_eq!(g.node_count(), 0);
+ assert_eq!(g.edge_count(), 0);
+ }
+
+ #[test]
+ fn test_node_indexing() {
+ let mut g: MatrixGraph<char, ()> = MatrixGraph::new();
+ let a = g.add_node('a');
+ let b = g.add_node('b');
+ assert_eq!(g.node_count(), 2);
+ assert_eq!(g.edge_count(), 0);
+ assert_eq!(g[a], 'a');
+ assert_eq!(g[b], 'b');
+ }
+
+ #[test]
+ fn test_remove_node() {
+ let mut g: MatrixGraph<char, ()> = MatrixGraph::new();
+ let a = g.add_node('a');
+
+ g.remove_node(a);
+
+ assert_eq!(g.node_count(), 0);
+ assert_eq!(g.edge_count(), 0);
+ }
+
+ #[test]
+ fn test_add_edge() {
+ let mut g = MatrixGraph::new();
+ let a = g.add_node('a');
+ let b = g.add_node('b');
+ let c = g.add_node('c');
+ g.add_edge(a, b, ());
+ g.add_edge(b, c, ());
+ assert_eq!(g.node_count(), 3);
+ assert_eq!(g.edge_count(), 2);
+ }
+
+ #[test]
+ /// Adds an edge that triggers a second extension of the matrix.
+ /// From #425
+ fn test_add_edge_with_extension() {
+ let mut g = DiMatrix::<u8, ()>::new();
+ let _n0 = g.add_node(0);
+ let n1 = g.add_node(1);
+ let n2 = g.add_node(2);
+ let n3 = g.add_node(3);
+ let n4 = g.add_node(4);
+ let _n5 = g.add_node(5);
+ g.add_edge(n2, n1, ());
+ g.add_edge(n2, n3, ());
+ g.add_edge(n2, n4, ());
+ assert_eq!(g.node_count(), 6);
+ assert_eq!(g.edge_count(), 3);
+ assert!(g.has_edge(n2, n1));
+ assert!(g.has_edge(n2, n3));
+ assert!(g.has_edge(n2, n4));
+ }
+
+ #[test]
+ fn test_matrix_resize() {
+ let mut g = DiMatrix::<u8, ()>::with_capacity(3);
+ let n0 = g.add_node(0);
+ let n1 = g.add_node(1);
+ let n2 = g.add_node(2);
+ let n3 = g.add_node(3);
+ g.add_edge(n1, n0, ());
+ g.add_edge(n1, n1, ());
+ // Triggers a resize from capacity 3 to 4
+ g.add_edge(n2, n3, ());
+ assert_eq!(g.node_count(), 4);
+ assert_eq!(g.edge_count(), 3);
+ assert!(g.has_edge(n1, n0));
+ assert!(g.has_edge(n1, n1));
+ assert!(g.has_edge(n2, n3));
+ }
+
+ #[test]
+ fn test_add_edge_with_weights() {
+ let mut g = MatrixGraph::new();
+ let a = g.add_node('a');
+ let b = g.add_node('b');
+ let c = g.add_node('c');
+ g.add_edge(a, b, true);
+ g.add_edge(b, c, false);
+ assert!(*g.edge_weight(a, b));
+ assert!(!*g.edge_weight(b, c));
+ }
+
+ #[test]
+ fn test_add_edge_with_weights_undirected() {
+ let mut g = MatrixGraph::new_undirected();
+ let a = g.add_node('a');
+ let b = g.add_node('b');
+ let c = g.add_node('c');
+ let d = g.add_node('d');
+ g.add_edge(a, b, "ab");
+ g.add_edge(a, a, "aa");
+ g.add_edge(b, c, "bc");
+ g.add_edge(d, d, "dd");
+ assert_eq!(*g.edge_weight(a, b), "ab");
+ assert_eq!(*g.edge_weight(b, c), "bc");
+ }
+
+ /// Shorthand for `.collect::<Vec<_>>()`
+ trait IntoVec<T> {
+ fn into_vec(self) -> Vec<T>;
+ }
+
+ impl<It, T> IntoVec<T> for It
+ where
+ It: Iterator<Item = T>,
+ {
+ fn into_vec(self) -> Vec<T> {
+ self.collect()
+ }
+ }
+
+ #[test]
+ fn test_clear() {
+ let mut g = MatrixGraph::new();
+ let a = g.add_node('a');
+ let b = g.add_node('b');
+ let c = g.add_node('c');
+ assert_eq!(g.node_count(), 3);
+
+ g.add_edge(a, b, ());
+ g.add_edge(b, c, ());
+ g.add_edge(c, a, ());
+ assert_eq!(g.edge_count(), 3);
+
+ g.clear();
+
+ assert_eq!(g.node_count(), 0);
+ assert_eq!(g.edge_count(), 0);
+
+ let a = g.add_node('a');
+ let b = g.add_node('b');
+ let c = g.add_node('c');
+ assert_eq!(g.node_count(), 3);
+ assert_eq!(g.edge_count(), 0);
+
+ assert_eq!(g.neighbors_directed(a, Incoming).into_vec(), vec![]);
+ assert_eq!(g.neighbors_directed(b, Incoming).into_vec(), vec![]);
+ assert_eq!(g.neighbors_directed(c, Incoming).into_vec(), vec![]);
+
+ assert_eq!(g.neighbors_directed(a, Outgoing).into_vec(), vec![]);
+ assert_eq!(g.neighbors_directed(b, Outgoing).into_vec(), vec![]);
+ assert_eq!(g.neighbors_directed(c, Outgoing).into_vec(), vec![]);
+ }
+
+ #[test]
+ fn test_clear_undirected() {
+ let mut g = MatrixGraph::new_undirected();
+ let a = g.add_node('a');
+ let b = g.add_node('b');
+ let c = g.add_node('c');
+ assert_eq!(g.node_count(), 3);
+
+ g.add_edge(a, b, ());
+ g.add_edge(b, c, ());
+ g.add_edge(c, a, ());
+ assert_eq!(g.edge_count(), 3);
+
+ g.clear();
+
+ assert_eq!(g.node_count(), 0);
+ assert_eq!(g.edge_count(), 0);
+
+ let a = g.add_node('a');
+ let b = g.add_node('b');
+ let c = g.add_node('c');
+ assert_eq!(g.node_count(), 3);
+ assert_eq!(g.edge_count(), 0);
+
+ assert_eq!(g.neighbors(a).into_vec(), vec![]);
+ assert_eq!(g.neighbors(b).into_vec(), vec![]);
+ assert_eq!(g.neighbors(c).into_vec(), vec![]);
+ }
+
+ /// Helper trait for always sorting before testing.
+ trait IntoSortedVec<T> {
+ fn into_sorted_vec(self) -> Vec<T>;
+ }
+
+ impl<It, T> IntoSortedVec<T> for It
+ where
+ It: Iterator<Item = T>,
+ T: Ord,
+ {
+ fn into_sorted_vec(self) -> Vec<T> {
+ let mut v: Vec<T> = self.collect();
+ v.sort();
+ v
+ }
+ }
+
+ /// Helper macro for always sorting before testing.
+ macro_rules! sorted_vec {
+ ($($x:expr),*) => {
+ {
+ let mut v = vec![$($x,)*];
+ v.sort();
+ v
+ }
+ }
+ }
+
+ #[test]
+ fn test_neighbors() {
+ let mut g = MatrixGraph::new();
+ let a = g.add_node('a');
+ let b = g.add_node('b');
+ let c = g.add_node('c');
+ g.add_edge(a, b, ());
+ g.add_edge(a, c, ());
+
+ let a_neighbors = g.neighbors(a).into_sorted_vec();
+ assert_eq!(a_neighbors, sorted_vec![b, c]);
+
+ let b_neighbors = g.neighbors(b).into_sorted_vec();
+ assert_eq!(b_neighbors, vec![]);
+
+ let c_neighbors = g.neighbors(c).into_sorted_vec();
+ assert_eq!(c_neighbors, vec![]);
+ }
+
+ #[test]
+ fn test_neighbors_undirected() {
+ let mut g = MatrixGraph::new_undirected();
+ let a = g.add_node('a');
+ let b = g.add_node('b');
+ let c = g.add_node('c');
+ g.add_edge(a, b, ());
+ g.add_edge(a, c, ());
+
+ let a_neighbors = g.neighbors(a).into_sorted_vec();
+ assert_eq!(a_neighbors, sorted_vec![b, c]);
+
+ let b_neighbors = g.neighbors(b).into_sorted_vec();
+ assert_eq!(b_neighbors, sorted_vec![a]);
+
+ let c_neighbors = g.neighbors(c).into_sorted_vec();
+ assert_eq!(c_neighbors, sorted_vec![a]);
+ }
+
+ #[test]
+ fn test_remove_node_and_edges() {
+ let mut g = MatrixGraph::new();
+ let a = g.add_node('a');
+ let b = g.add_node('b');
+ let c = g.add_node('c');
+ g.add_edge(a, b, ());
+ g.add_edge(b, c, ());
+ g.add_edge(c, a, ());
+
+ // removing b should break the `a -> b` and `b -> c` edges
+ g.remove_node(b);
+
+ assert_eq!(g.node_count(), 2);
+
+ let a_neighbors = g.neighbors(a).into_sorted_vec();
+ assert_eq!(a_neighbors, vec![]);
+
+ let c_neighbors = g.neighbors(c).into_sorted_vec();
+ assert_eq!(c_neighbors, vec![a]);
+ }
+
+ #[test]
+ fn test_remove_node_and_edges_undirected() {
+ let mut g = UnMatrix::new_undirected();
+ let a = g.add_node('a');
+ let b = g.add_node('b');
+ let c = g.add_node('c');
+ g.add_edge(a, b, ());
+ g.add_edge(b, c, ());
+ g.add_edge(c, a, ());
+
+ // removing a should break the `a - b` and `a - c` edges
+ g.remove_node(a);
+
+ assert_eq!(g.node_count(), 2);
+
+ let b_neighbors = g.neighbors(b).into_sorted_vec();
+ assert_eq!(b_neighbors, vec![c]);
+
+ let c_neighbors = g.neighbors(c).into_sorted_vec();
+ assert_eq!(c_neighbors, vec![b]);
+ }
+
+ #[test]
+ fn test_node_identifiers() {
+ let mut g = MatrixGraph::new();
+ let a = g.add_node('a');
+ let b = g.add_node('b');
+ let c = g.add_node('c');
+ let d = g.add_node('c');
+ g.add_edge(a, b, ());
+ g.add_edge(a, c, ());
+
+ let node_ids = g.node_identifiers().into_sorted_vec();
+ assert_eq!(node_ids, sorted_vec![a, b, c, d]);
+ }
+
+ #[test]
+ fn test_edges_directed() {
+ let g: MatrixGraph<char, bool> = MatrixGraph::from_edges(&[
+ (0, 5),
+ (0, 2),
+ (0, 3),
+ (0, 1),
+ (1, 3),
+ (2, 3),
+ (2, 4),
+ (4, 0),
+ (6, 6),
+ ]);
+
+ assert_eq!(g.edges_directed(node_index(0), Outgoing).count(), 4);
+ assert_eq!(g.edges_directed(node_index(1), Outgoing).count(), 1);
+ assert_eq!(g.edges_directed(node_index(2), Outgoing).count(), 2);
+ assert_eq!(g.edges_directed(node_index(3), Outgoing).count(), 0);
+ assert_eq!(g.edges_directed(node_index(4), Outgoing).count(), 1);
+ assert_eq!(g.edges_directed(node_index(5), Outgoing).count(), 0);
+ assert_eq!(g.edges_directed(node_index(6), Outgoing).count(), 1);
+
+ assert_eq!(g.edges_directed(node_index(0), Incoming).count(), 1);
+ assert_eq!(g.edges_directed(node_index(1), Incoming).count(), 1);
+ assert_eq!(g.edges_directed(node_index(2), Incoming).count(), 1);
+ assert_eq!(g.edges_directed(node_index(3), Incoming).count(), 3);
+ assert_eq!(g.edges_directed(node_index(4), Incoming).count(), 1);
+ assert_eq!(g.edges_directed(node_index(5), Incoming).count(), 1);
+ assert_eq!(g.edges_directed(node_index(6), Incoming).count(), 1);
+ }
+
+ #[test]
+ fn test_edges_undirected() {
+ let g: UnMatrix<char, bool> = UnMatrix::from_edges(&[
+ (0, 5),
+ (0, 2),
+ (0, 3),
+ (0, 1),
+ (1, 3),
+ (2, 3),
+ (2, 4),
+ (4, 0),
+ (6, 6),
+ ]);
+
+ assert_eq!(g.edges(node_index(0)).count(), 5);
+ assert_eq!(g.edges(node_index(1)).count(), 2);
+ assert_eq!(g.edges(node_index(2)).count(), 3);
+ assert_eq!(g.edges(node_index(3)).count(), 3);
+ assert_eq!(g.edges(node_index(4)).count(), 2);
+ assert_eq!(g.edges(node_index(5)).count(), 1);
+ assert_eq!(g.edges(node_index(6)).count(), 1);
+ }
+
+ #[test]
+ fn test_edges_of_absent_node_is_empty_iterator() {
+ let g: MatrixGraph<char, bool> = MatrixGraph::new();
+ assert_eq!(g.edges(node_index(0)).count(), 0);
+ }
+
+ #[test]
+ fn test_neighbors_of_absent_node_is_empty_iterator() {
+ let g: MatrixGraph<char, bool> = MatrixGraph::new();
+ assert_eq!(g.neighbors(node_index(0)).count(), 0);
+ }
+
+ #[test]
+ fn test_edge_references() {
+ let g: MatrixGraph<char, bool> = MatrixGraph::from_edges(&[
+ (0, 5),
+ (0, 2),
+ (0, 3),
+ (0, 1),
+ (1, 3),
+ (2, 3),
+ (2, 4),
+ (4, 0),
+ (6, 6),
+ ]);
+
+ assert_eq!(g.edge_references().count(), 9);
+ }
+
+ #[test]
+ fn test_edge_references_undirected() {
+ let g: UnMatrix<char, bool> = UnMatrix::from_edges(&[
+ (0, 5),
+ (0, 2),
+ (0, 3),
+ (0, 1),
+ (1, 3),
+ (2, 3),
+ (2, 4),
+ (4, 0),
+ (6, 6),
+ ]);
+
+ assert_eq!(g.edge_references().count(), 9);
+ }
+
+ #[test]
+ fn test_id_storage() {
+ use super::IdStorage;
+
+ let mut storage: IdStorage<char> = IdStorage::with_capacity(0);
+ let a = storage.add('a');
+ let b = storage.add('b');
+ let c = storage.add('c');
+
+ assert!(a < b && b < c);
+
+ // list IDs
+ assert_eq!(storage.iter_ids().into_vec(), vec![a, b, c]);
+
+ storage.remove(b);
+
+ // re-use of IDs
+ let bb = storage.add('B');
+ assert_eq!(b, bb);
+
+ // list IDs
+ assert_eq!(storage.iter_ids().into_vec(), vec![a, b, c]);
+ }
+
+ #[test]
+ fn test_not_zero() {
+ let mut g: MatrixGraph<(), i32, Directed, NotZero<i32>> = MatrixGraph::default();
+
+ let a = g.add_node(());
+ let b = g.add_node(());
+
+ assert!(!g.has_edge(a, b));
+ assert_eq!(g.edge_count(), 0);
+
+ g.add_edge(a, b, 12);
+
+ assert!(g.has_edge(a, b));
+ assert_eq!(g.edge_count(), 1);
+ assert_eq!(g.edge_weight(a, b), &12);
+
+ g.remove_edge(a, b);
+
+ assert!(!g.has_edge(a, b));
+ assert_eq!(g.edge_count(), 0);
+ }
+
+ #[test]
+ #[should_panic]
+ fn test_not_zero_asserted() {
+ let mut g: MatrixGraph<(), i32, Directed, NotZero<i32>> = MatrixGraph::default();
+
+ let a = g.add_node(());
+ let b = g.add_node(());
+
+ g.add_edge(a, b, 0); // this should trigger an assertion
+ }
+
+ #[test]
+ fn test_not_zero_float() {
+ let mut g: MatrixGraph<(), f32, Directed, NotZero<f32>> = MatrixGraph::default();
+
+ let a = g.add_node(());
+ let b = g.add_node(());
+
+ assert!(!g.has_edge(a, b));
+ assert_eq!(g.edge_count(), 0);
+
+ g.add_edge(a, b, 12.);
+
+ assert!(g.has_edge(a, b));
+ assert_eq!(g.edge_count(), 1);
+ assert_eq!(g.edge_weight(a, b), &12.);
+
+ g.remove_edge(a, b);
+
+ assert!(!g.has_edge(a, b));
+ assert_eq!(g.edge_count(), 0);
+ }
+ #[test]
+ // From https://github.com/petgraph/petgraph/issues/523
+ fn test_tarjan_scc_with_removed_node() {
+ let mut g: MatrixGraph<(), ()> = MatrixGraph::new();
+
+ g.add_node(());
+ let b = g.add_node(());
+ g.add_node(());
+
+ g.remove_node(b);
+
+ assert_eq!(
+ crate::algo::tarjan_scc(&g),
+ [[node_index(0)], [node_index(2)]]
+ );
+ }
+
+ #[test]
+ // From https://github.com/petgraph/petgraph/issues/523
+ fn test_kosaraju_scc_with_removed_node() {
+ let mut g: MatrixGraph<(), ()> = MatrixGraph::new();
+
+ g.add_node(());
+ let b = g.add_node(());
+ g.add_node(());
+
+ g.remove_node(b);
+
+ assert_eq!(
+ crate::algo::kosaraju_scc(&g),
+ [[node_index(2)], [node_index(0)]]
+ );
+ }
+}
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