Merge pull request #273 from ultrasaurus/doc-indices
attempt to clarify index documentation
diff --git a/Cargo.toml b/Cargo.toml
index 1221614..df77606 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -28,7 +28,7 @@
debug = true
[dependencies]
-fixedbitset = { version = "0.1.4" }
+fixedbitset = { version = "0.2.0", default-features = false }
quickcheck = { optional = true, version = "0.8", default-features = false }
indexmap = { version = "1.0.2", optional = true }
serde = { version = "1.0", optional = true }
@@ -41,17 +41,18 @@
itertools = { version = "0.8", default-features = false }
[features]
-default = ["graphmap", "stable_graph"]
+default = ["graphmap", "stable_graph", "matrix_graph"]
graphmap = ["indexmap"]
serde-1 = ["serde", "serde_derive"]
stable_graph = []
+matrix_graph = []
# For unstable features
generate = []
unstable = ["generate"]
# feature flags for testing use only
-all = ["unstable", "quickcheck", "stable_graph", "graphmap"]
+all = ["unstable", "quickcheck", "matrix_graph", "stable_graph", "graphmap"]
[workspace]
members = ["serialization-tests"]
diff --git a/README.rst b/README.rst
index 5cabe87..dff5633 100644
--- a/README.rst
+++ b/README.rst
@@ -20,6 +20,7 @@
- ``graphmap`` (default) enable ``GraphMap``.
- ``stable_graph`` (default) enable ``StableGraph``.
+- ``matrix_graph`` (default) enable ``MatrixGraph``.
- ``serde-1`` (optional) enable serialization for ``Graph, StableGraph`` using
serde 1.0. Requires Rust version as required by serde.
diff --git a/benches/matrix_graph.rs b/benches/matrix_graph.rs
new file mode 100644
index 0000000..ef81733
--- /dev/null
+++ b/benches/matrix_graph.rs
@@ -0,0 +1,237 @@
+#![feature(test)]
+
+extern crate petgraph;
+extern crate test;
+
+use test::Bencher;
+
+use petgraph::{EdgeType, Directed, Outgoing, Incoming};
+use petgraph::algo;
+use petgraph::matrix_graph::{MatrixGraph, node_index};
+
+#[bench]
+fn add_100_nodes(b: &mut test::Bencher) {
+ b.iter(|| {
+ let mut g = MatrixGraph::<(), ()>::with_capacity(100);
+
+ for _ in 0..100 {
+ let _ = g.add_node(());
+ }
+ });
+}
+
+#[bench]
+fn add_100_edges_to_self(b: &mut test::Bencher) {
+ let mut g = MatrixGraph::<(), ()>::with_capacity(100);
+ let nodes: Vec<_> = (0..100).map(|_| g.add_node(())).collect();
+ let g = g;
+
+ b.iter(|| {
+ let mut g = g.clone();
+
+ for &node in nodes.iter() {
+ let _ = g.add_edge(node, node, ());
+ }
+ });
+}
+
+#[bench]
+fn add_5_edges_for_each_of_100_nodes(b: &mut test::Bencher) {
+ let mut g = MatrixGraph::<(), ()>::with_capacity(100);
+ let nodes: Vec<_> = (0..100).map(|_| g.add_node(())).collect();
+ let g = g;
+
+ let edges_to_add: Vec<_> = nodes.iter()
+ .enumerate()
+ .map(|(i, &node)| {
+ let edges: Vec<_> = (0..5)
+ .map(|j| (i + j + 1) % nodes.len())
+ .map(|j| (node, nodes[j]))
+ .collect();
+
+ edges
+ })
+ .flat_map(|e| e)
+ .collect();
+
+ b.iter(|| {
+ let mut g = g.clone();
+
+ for &(source, target) in edges_to_add.iter() {
+ let _ = g.add_edge(source, target, ());
+ }
+ });
+}
+
+#[bench]
+fn add_edges_from_root(bench: &mut test::Bencher) {
+ bench.iter(|| {
+ let mut gr = MatrixGraph::new();
+ let a = gr.add_node(());
+
+ for _ in 0..100 {
+ let b = gr.add_node(());
+ gr.add_edge(a, b, ());
+ }
+ });
+}
+
+#[bench]
+fn add_adjacent_edges(bench: &mut test::Bencher) {
+ bench.iter(|| {
+ let mut gr = MatrixGraph::new();
+ let mut prev = None;
+ for _ in 0..100 {
+ let b = gr.add_node(());
+
+ if let Some(a) = prev {
+ gr.add_edge(a, b, ());
+ }
+
+ prev = Some(b);
+ }
+ });
+}
+
+/// An almost full set
+const FULL: &'static str = "
+ 1 1 1 1 1 1 1 1 1 1
+ 1 1 1 1 1 1 1 1 1 1
+ 1 1 1 1 1 1 1 1 1 1
+ 1 1 1 1 1 1 1 1 1 1
+ 1 1 1 1 1 1 1 1 1 1
+ 1 1 1 1 1 1 1 1 1 1
+ 1 1 1 1 1 1 1 1 1 1
+ 1 1 1 1 1 1 1 1 1 1
+ 1 1 1 1 0 1 1 1 0 1
+ 1 1 1 1 1 1 1 1 1 1
+";
+
+const BIGGER: &'static str = "
+ 0 0 0 0 0 0 0 0 1 0 1 0 0 0 0 0 0 0 1 1 0 1 1 1 1 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0
+ 0 0 0 0 0 1 0 0 0 1 1 0 0 0 0 0 0 0 1 0 1 0 1 1 0 1 0 0 0 1 0 0 0 0 0 0 0 0 0 0
+ 0 1 0 1 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 1 1 0 1 0 0 1 0 0 0 1 0 0 0 0 0 0 0 0 0
+ 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
+ 0 0 0 1 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
+ 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
+ 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
+ 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
+ 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
+ 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
+ 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
+ 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
+ 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 1 0 1 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 1 1 1 0 1 0 0
+ 0 0 0 0 0 1 0 0 0 0 0 0 1 0 0 1 1 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 1 0 1 1 1 0 0 0
+ 0 0 0 0 0 0 1 0 0 0 0 0 1 1 0 1 0 0 0 1 0 0 0 0 0 0 1 0 0 0 0 0 1 1 0 1 0 0 0 1
+ 0 0 0 0 0 0 0 1 0 0 0 0 1 1 1 0 0 0 1 0 0 0 0 0 0 0 0 1 0 0 0 0 1 1 1 0 0 0 1 0
+ 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 1 1 1 0 1 1 0 0 0 0 0 1 0 0 0 0 1 0 0 0 1 1 1
+ 0 0 0 0 1 0 0 0 0 0 0 0 1 0 0 0 1 0 1 1 0 1 1 1 0 0 0 0 0 1 0 0 1 0 0 0 1 0 1 1
+ 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 1 1 1 0 1
+ 0 0 0 0 0 0 0 0 0 0 0 1 0 0 1 0 1 1 1 1 0 0 0 0 0 0 0 0 0 0 0 1 0 0 1 0 1 1 1 0
+ 0 1 1 0 1 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 1 1 1 1 1 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0
+ 1 0 1 0 0 1 0 0 0 1 0 0 0 0 0 0 0 1 1 0 1 0 1 1 0 1 0 0 0 1 0 0 0 0 0 0 0 0 0 0
+ 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
+ 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
+ 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
+ 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
+ 0 0 1 0 1 1 0 1 0 0 0 0 0 0 1 0 0 0 0 0 0 0 1 0 1 1 0 1 0 0 0 0 0 0 1 0 0 0 0 0
+ 0 0 0 0 1 1 1 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 1 1 1 1 0 0 0 0 0 0 0 0 1 0 0 0 0
+ 1 0 0 0 0 0 0 0 0 1 1 1 0 0 0 0 1 0 0 0 1 0 0 0 0 0 0 0 0 1 1 1 0 0 0 0 1 0 0 0
+ 0 1 0 0 0 0 0 0 1 0 1 1 0 0 0 0 0 1 0 0 0 1 0 0 0 0 0 0 1 0 1 1 0 0 0 0 0 1 0 0
+ 0 0 1 0 0 0 0 0 1 1 0 1 0 0 0 0 0 0 1 0 0 0 1 0 0 0 0 0 1 1 0 1 0 0 0 0 0 0 1 0
+ 0 0 0 1 0 0 0 0 1 1 1 0 0 0 0 0 0 0 0 1 0 0 0 1 0 0 0 0 1 1 1 0 0 0 0 0 0 0 0 1
+ 0 0 0 0 1 0 0 0 0 0 0 0 0 1 1 1 0 1 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 1 1 1 0 1 0 0
+ 0 0 0 0 0 1 0 0 0 0 0 0 1 0 1 1 1 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 1 0 1 1 1 0 0 0
+ 0 1 0 0 0 0 1 0 0 0 0 0 1 1 0 1 0 0 0 1 0 0 0 0 0 0 1 0 0 0 0 0 1 1 0 1 0 0 0 1
+ 0 1 0 0 0 0 0 1 0 0 0 0 1 1 1 0 0 0 1 0 0 0 0 0 0 0 0 1 0 0 0 0 1 1 1 0 0 0 1 0
+ 0 1 0 0 0 0 0 0 1 0 0 0 0 1 0 0 0 1 1 1 0 0 0 0 0 0 0 0 1 0 0 0 0 1 0 0 0 1 1 1
+ 0 1 0 0 0 0 0 0 0 1 0 0 1 0 0 0 1 0 1 1 0 0 0 0 0 0 0 0 0 1 0 0 1 0 0 0 1 0 1 1
+ 0 1 0 0 0 0 0 0 0 0 1 0 0 0 0 1 1 1 0 1 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 1 1 1 0 1
+ 0 1 0 0 0 0 0 0 0 0 0 1 0 0 1 0 1 1 1 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 1 0 1 1 1 0
+";
+
+/// Parse a text adjacency matrix format into a directed graph
+fn parse_matrix<Ty: EdgeType>(s: &str) -> MatrixGraph<(), (), Ty> {
+ let mut gr = MatrixGraph::default();
+ let s = s.trim();
+ let lines = s.lines().filter(|l| !l.is_empty());
+ for (row, line) in lines.enumerate() {
+ for (col, word) in line.split(' ')
+ .filter(|s| s.len() > 0)
+ .enumerate()
+ {
+ let has_edge = word.parse::<i32>().unwrap();
+ assert!(has_edge == 0 || has_edge == 1);
+ if has_edge == 0 {
+ continue;
+ }
+ while col >= gr.node_count() || row >= gr.node_count() {
+ gr.add_node(());
+ }
+ gr.add_edge(node_index(row), node_index(col), ());
+ }
+ }
+ gr
+}
+
+#[bench]
+fn full_edges_out(bench: &mut Bencher) {
+ let a = parse_matrix::<Directed>(FULL);
+ bench.iter(|| a.edges_directed(node_index(1), Outgoing).count())
+}
+
+#[bench]
+fn full_edges_in(bench: &mut Bencher) {
+ let a = parse_matrix::<Directed>(FULL);
+ bench.iter(|| a.edges_directed(node_index(1), Incoming).count())
+}
+
+#[bench]
+fn full_neighbors_out(bench: &mut Bencher) {
+ let a = parse_matrix::<Directed>(FULL);
+ bench.iter(|| a.neighbors_directed(node_index(1), Outgoing).count())
+}
+
+#[bench]
+fn full_neighbors_in(bench: &mut Bencher) {
+ let a = parse_matrix::<Directed>(FULL);
+
+ bench.iter(|| a.neighbors_directed(node_index(1), Incoming).count())
+}
+
+#[bench]
+fn full_sccs(bench: &mut Bencher) {
+ let a = parse_matrix::<Directed>(FULL);
+ bench.iter(|| algo::kosaraju_scc(&a));
+}
+
+#[bench]
+fn bigger_edges_out(bench: &mut Bencher) {
+ let a = parse_matrix::<Directed>(BIGGER);
+ bench.iter(|| a.edges_directed(node_index(1), Outgoing).count())
+}
+
+#[bench]
+fn bigger_edges_in(bench: &mut Bencher) {
+ let a = parse_matrix::<Directed>(BIGGER);
+ bench.iter(|| a.edges_directed(node_index(1), Incoming).count())
+}
+
+#[bench]
+fn bigger_neighbors_out(bench: &mut Bencher) {
+ let a = parse_matrix::<Directed>(BIGGER);
+ bench.iter(|| a.neighbors_directed(node_index(1), Outgoing).count())
+}
+
+#[bench]
+fn bigger_neighbors_in(bench: &mut Bencher) {
+ let a = parse_matrix::<Directed>(BIGGER);
+
+ bench.iter(|| a.neighbors_directed(node_index(1), Incoming).count())
+}
+
+#[bench]
+fn bigger_sccs(bench: &mut Bencher) {
+ let a = parse_matrix::<Directed>(BIGGER);
+ bench.iter(|| algo::kosaraju_scc(&a));
+}
diff --git a/src/lib.rs b/src/lib.rs
index 5febc29..4a76111 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -10,6 +10,9 @@
//! - [`GraphMap`](./graphmap/struct.GraphMap.html) is an adjacency list graph
//! which is backed by a hash table and the node identifiers are the keys
//! into the table.
+//!
+//! - [`MatrixGraph`](./matrix_graph/struct.MatrixGraph.html) is an adjacency matrix graph.
+//!
//! - [`CSR`](./csr/struct.Csr.html) is a sparse adjacency matrix graph with
//! arbitrary associated data.
//!
@@ -50,6 +53,8 @@
pub mod generate;
#[cfg(feature = "graphmap")]
pub mod graphmap;
+#[cfg(feature = "matrix_graph")]
+pub mod matrix_graph;
mod graph_impl;
pub mod dot;
pub mod unionfind;
diff --git a/src/matrix_graph.rs b/src/matrix_graph.rs
new file mode 100644
index 0000000..3d2bd8a
--- /dev/null
+++ b/src/matrix_graph.rs
@@ -0,0 +1,1565 @@
+//! `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,
+ EdgeType,
+ Outgoing,
+ Undirected,
+ Direction,
+ IntoWeightedEdge,
+};
+
+use crate::graph::NodeIndex as GraphNodeIndex;
+
+use crate::visit::{
+ Data,
+ GetAdjacencyMatrix,
+ GraphBase,
+ GraphProp,
+ IntoEdgeReferences,
+ IntoEdges,
+ IntoNeighbors,
+ IntoNeighborsDirected,
+ IntoNodeIdentifiers,
+ IntoNodeReferences,
+ NodeCount,
+ NodeIndexable,
+ NodeCompactIndexable,
+ 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> {
+ type Wrapped = T;
+
+ fn new(value: T) -> Self {
+ assert!(!value.is_zero());
+ NotZero(value)
+ }
+
+ // implemented here for optimization purposes
+ fn is_null(&self) -> bool {
+ self.0.is_zero()
+ }
+
+ fn as_ref(&self) -> Option<&Self::Wrapped> {
+ if !self.is_null() { Some(&self.0) }
+ else { None }
+ }
+
+ fn as_mut(&mut self) -> Option<&mut Self::Wrapped> {
+ if !self.is_null() { Some(&mut self.0) }
+ else { None }
+ }
+}
+
+impl<T: Zero> Into<Option<T>> for NotZero<T> {
+ fn into(self) -> Option<T> {
+ if !self.is_null() { Some(self.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 $t
+ }
+
+ fn is_zero(&self) -> bool {
+ self == &Self::zero()
+ }
+ }
+ }
+}
+
+macro_rules! not_zero_impls {
+ ($($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());
+ m.extend_capacity_for_node(NodeIndex::new(node_capacity));
+
+ m
+ }
+
+ #[inline]
+ fn to_edge_position(&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));
+ self.node_adjacencies[position] = Default::default();
+
+ if Ty::is_directed() {
+ let position = self.to_edge_position(NodeIndex::new(id), a);
+ self.node_adjacencies[position] = Default::default();
+ }
+ }
+
+ self.nodes.remove(a.index())
+ }
+
+ #[inline]
+ fn extend_capacity_for_node(&mut self, min_node: NodeIndex<Ix>) {
+ self.node_capacity = extend_linearized_matrix::<Ty, _>(&mut self.node_adjacencies, self.node_capacity, min_node.index());
+ }
+
+ #[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);
+ }
+ }
+
+ /// 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(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`.
+ ///
+ /// Return the index of the new edge.
+ ///
+ /// 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);
+ let old_weight = mem::replace(&mut self.node_adjacencies[p], Default::default()).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 {
+ let p = self.to_edge_position(a, b);
+ !self.node_adjacencies[p].is_null()
+ }
+
+ /// 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);
+ self.node_adjacencies[p].as_ref().unwrap()
+ }
+
+ /// 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);
+ self.node_adjacencies[p].as_mut().unwrap()
+ }
+
+ /// 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 [`Edges<E, Ix>`](../graph/struct.Edges.html).
+ 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)*.
+ ///
+ /// - `Directed`, `Outgoing`: All edges from `a`.
+ /// - `Directed`, `Incoming`: All edges to `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_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.
+ ///
+ /// - `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 `a` doesn't exist.<br>
+ /// Iterator element type is [`EdgeReference<E, Ix>`](../graph/struct.EdgeReference.html).
+ 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
+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<'a, Ix: IndexType> Iterator for NodeIdentifiers<'a, Ix> {
+ type Item = NodeIndex<Ix>;
+
+ fn next(&mut self) -> Option<Self::Item> {
+ self.iter.next().map(NodeIndex::new)
+ }
+}
+
+/// 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
+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: 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]))
+ }
+}
+
+/// 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
+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_adjacencies,
+ node_capacity: 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
+pub struct Neighbors<'a, Ty: EdgeType, Null: 'a + Nullable, Ix>(Edges<'a, Ty, Null, Ix>);
+
+impl<'a, Ty: EdgeType, Null: Nullable, Ix: IndexType> Iterator for Neighbors<'a, Ty, Null, Ix> {
+ type Item = NodeIndex<Ix>;
+
+ fn next(&mut self) -> Option<Self::Item> {
+ self.0.next().map(|(_, b, _)| b)
+ }
+}
+
+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
+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_adjacencies,
+ node_capacity: node_capacity,
+ row: 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_adjacencies,
+ node_capacity: node_capacity,
+ row: 0,
+ column: 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, min_node_capacity: usize) -> usize {
+ if Ty::is_directed() {
+ extend_flat_square_matrix(node_adjacencies, old_node_capacity, min_node_capacity)
+ } else {
+ extend_lower_triangular_matrix(node_adjacencies, min_node_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, min_node_capacity: usize) -> usize {
+ let min_node_capacity = (min_node_capacity + 1).next_power_of_two();
+
+ // Optimization: when resizing the matrix this way we skip the first few grows to make
+ // small matrices a bit faster to work with.
+ const MIN_CAPACITY: usize = 4;
+ let new_node_capacity = cmp::max(min_node_capacity, MIN_CAPACITY);
+
+ let mut new_node_adjacencies = vec![];
+ ensure_len(&mut new_node_adjacencies, new_node_capacity.pow(2));
+
+ for c in 0..old_node_capacity {
+ let pos = c * old_node_capacity;
+ let new_pos = c * new_node_capacity;
+
+ let mut old = &mut node_adjacencies[pos..pos + old_node_capacity];
+ let mut new = &mut new_node_adjacencies[new_pos..new_pos + old_node_capacity];
+
+ mem::swap(&mut old, &mut new);
+ }
+
+ mem::swap(node_adjacencies, &mut new_node_adjacencies);
+
+ 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_node_capacity: usize) -> usize {
+ let max_pos = to_lower_triangular_matrix_position(new_node_capacity, new_node_capacity);
+ ensure_len(node_adjacencies, max_pos + 1);
+ new_node_capacity + 1
+}
+
+/// Grow a Vec by appending the type's default value the `size` is reached.
+fn ensure_len<T: Default>(v: &mut Vec<T>, size: usize) {
+ if let Some(n) = size.checked_sub(v.len()) {
+ v.reserve(n);
+ for _ in 0..n {
+ v.push(T::default());
+ }
+ }
+}
+
+#[derive(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()
+ }
+}
+
+struct IdIterator<'a> {
+ upper_bound: usize,
+ removed_ids: &'a IndexSet<usize>,
+ current: Option<usize>,
+}
+
+impl<'a> Iterator for IdIterator<'a> {
+ 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)
+ }
+}
+
+/// 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_count())
+ }
+
+ fn reset_map(&self, map: &mut Self::Map) {
+ map.clear();
+ map.grow(self.node_count());
+ }
+}
+
+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<N, E, Ty: EdgeType, Null: Nullable<Wrapped=E>, Ix: IndexType> NodeIndexable for MatrixGraph<N, E, Ty, Null, Ix> {
+ fn node_bound(&self) -> usize {
+ self.node_count()
+ }
+
+ 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> NodeCompactIndexable for MatrixGraph<N, E, Ty, Null, 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::{Outgoing, Incoming};
+
+ #[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]
+ 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_eq!(*g.edge_weight(a, b), true);
+ assert_eq!(*g.edge_weight(b, c), false);
+ }
+
+ #[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);
+ }
+}
