1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
use itertools::Itertools;
use petgraph::matrix_graph::{MatrixGraph, NodeIndex, UnMatrix, Zero};
use petgraph::visit::IntoEdgeReferences;
use std::{collections::HashMap, hash::Hash};
pub type Idx = NodeIndex;
pub struct BoolIdx(bool);
impl From<bool> for BoolIdx {
fn from(b: bool) -> Self {
BoolIdx(b)
}
}
impl Zero for BoolIdx {
fn zero() -> Self {
BoolIdx(false)
}
fn is_zero(&self) -> bool {
!self.0
}
}
pub struct WeightGraph<T> {
pub index_map: HashMap<T, NodeIndex>,
pub graph: UnMatrix<(), BoolIdx>,
}
impl<T: Eq + Hash + Clone + Ord> Default for WeightGraph<T> {
fn default() -> Self {
WeightGraph {
index_map: HashMap::new(),
graph: MatrixGraph::new_undirected(),
}
}
}
impl<T, C> From<C> for WeightGraph<T>
where
T: Eq + Hash + Ord,
C: Iterator<Item = T>,
{
fn from(nodes: C) -> Self {
let mut graph = MatrixGraph::new_undirected();
let index_map: HashMap<_, _> =
nodes.map(|node| (node, graph.add_node(()))).collect();
WeightGraph { index_map, graph }
}
}
impl<'a, T> WeightGraph<T>
where
T: 'a + Eq + Hash + Clone + Ord,
{
#[inline(always)]
pub fn add_edge(&mut self, a: &T, b: &T) {
self.graph.update_edge(
self.index_map[a],
self.index_map[b],
true.into(),
);
}
pub fn add_all_edges<C>(&mut self, items: C)
where
C: Iterator<Item = &'a T> + Clone,
{
items.tuple_combinations().for_each(|(src, dst)| {
self.add_edge(src, dst);
});
}
#[inline(always)]
pub fn contains_node(&self, node: &T) -> bool {
self.index_map.contains_key(node)
}
pub fn add_node(&mut self, node: T) {
debug_assert!(
!self.index_map.contains_key(&node),
"Attempted to add pre-existing node to WeightGraph. Client code should ensure that this never happens.");
let idx = self.graph.add_node(());
self.index_map.insert(node, idx);
}
pub fn reverse_index(&self) -> HashMap<NodeIndex, T> {
self.index_map
.iter()
.map(|(k, v)| (*v, k.clone()))
.collect()
}
pub fn nodes(&self) -> impl Iterator<Item = &T> {
self.index_map.keys()
}
pub fn degree(&self, node: &T) -> usize {
self.graph.neighbors(self.index_map[node]).count()
}
}
impl<T: Eq + Hash + ToString + Clone + Ord> ToString for WeightGraph<T> {
fn to_string(&self) -> String {
let rev_map = self.reverse_index();
let keys: Vec<_> = self.index_map.keys().collect();
let nodes = keys
.iter()
.enumerate()
.map(|(_idx, key)| {
format!(
" {} [label=\"{}\"];",
key.to_string(),
key.to_string()
)
})
.collect::<Vec<_>>()
.join("\n");
let edges = self
.graph
.edge_references()
.map(|(a_idx, b_idx, _)| {
format!(
" {} -- {};",
rev_map[&a_idx].to_string(),
rev_map[&b_idx].to_string()
)
})
.collect::<Vec<_>>()
.join("\n");
format!("graph {{ \n{}\n{}\n }}", nodes, edges)
}
}