• Home
  • Features
  • Pricing
  • Docs
  • Announcements
  • Sign In

lightningnetwork / lnd / 13035292482

29 Jan 2025 03:59PM UTC coverage: 49.3% (-9.5%) from 58.777%
13035292482

Pull #9456

github

mohamedawnallah
docs: update release-notes-0.19.0.md

In this commit, we warn users about the removal
of RPCs `SendToRoute`, `SendToRouteSync`, `SendPayment`,
and `SendPaymentSync` in the next release 0.20.
Pull Request #9456: lnrpc+docs: deprecate warning `SendToRoute`, `SendToRouteSync`, `SendPayment`, and `SendPaymentSync` in Release 0.19

100634 of 204126 relevant lines covered (49.3%)

1.54 hits per line

Source File
Press 'n' to go to next uncovered line, 'b' for previous

3.66
/autopilot/betweenness_centrality.go
1
package autopilot
2

3
import (
4
        "fmt"
5
        "sync"
6
)
7

8
// stack is a simple int stack to help with readability of Brandes'
9
// betweenness centrality implementation below.
10
type stack struct {
11
        stack []int
12
}
13

14
func (s *stack) push(v int) {
×
15
        s.stack = append(s.stack, v)
×
16
}
×
17

18
func (s *stack) top() int {
×
19
        return s.stack[len(s.stack)-1]
×
20
}
×
21

22
func (s *stack) pop() {
×
23
        s.stack = s.stack[:len(s.stack)-1]
×
24
}
×
25

26
func (s *stack) empty() bool {
×
27
        return len(s.stack) == 0
×
28
}
×
29

30
// queue is a simple int queue to help with readability of Brandes'
31
// betweenness centrality implementation below.
32
type queue struct {
33
        queue []int
34
}
35

36
func (q *queue) push(v int) {
×
37
        q.queue = append(q.queue, v)
×
38
}
×
39

40
func (q *queue) front() int {
×
41
        return q.queue[0]
×
42
}
×
43

44
func (q *queue) pop() {
×
45
        q.queue = q.queue[1:]
×
46
}
×
47

48
func (q *queue) empty() bool {
×
49
        return len(q.queue) == 0
×
50
}
×
51

52
// BetweennessCentrality is a NodeMetric that calculates node betweenness
53
// centrality using Brandes' algorithm. Betweenness centrality for each node
54
// is the number of shortest paths passing through that node, not counting
55
// shortest paths starting or ending at that node. This is a useful metric
56
// to measure control of individual nodes over the whole network.
57
type BetweennessCentrality struct {
58
        // workers number of goroutines are used to parallelize
59
        // centrality calculation.
60
        workers int
61

62
        // centrality stores original (not normalized) centrality values for
63
        // each node in the graph.
64
        centrality map[NodeID]float64
65

66
        // min is the minimum centrality in the graph.
67
        min float64
68

69
        // max is the maximum centrality in the graph.
70
        max float64
71
}
72

73
// NewBetweennessCentralityMetric creates a new BetweennessCentrality instance.
74
// Users can specify the number of workers to use for calculating centrality.
75
func NewBetweennessCentralityMetric(workers int) (*BetweennessCentrality, error) {
3✔
76
        // There should be at least one worker.
3✔
77
        if workers < 1 {
3✔
78
                return nil, fmt.Errorf("workers must be positive")
×
79
        }
×
80
        return &BetweennessCentrality{
3✔
81
                workers: workers,
3✔
82
        }, nil
3✔
83
}
84

85
// Name returns the name of the metric.
86
func (bc *BetweennessCentrality) Name() string {
×
87
        return "betweenness_centrality"
×
88
}
×
89

90
// betweennessCentrality is the core of Brandes' algorithm.
91
// We first calculate the shortest paths from the start node s to all other
92
// nodes with BFS, then update the betweenness centrality values by using
93
// Brandes' dependency trick.
94
// For detailed explanation please read:
95
// https://www.cl.cam.ac.uk/teaching/1617/MLRD/handbook/brandes.html
96
func betweennessCentrality(g *SimpleGraph, s int, centrality []float64) {
×
97
        // pred[w] is the list of nodes that immediately precede w on a
×
98
        // shortest path from s to t for each node t.
×
99
        pred := make([][]int, len(g.Nodes))
×
100

×
101
        // sigma[t] is the number of shortest paths between nodes s and t
×
102
        // for each node t.
×
103
        sigma := make([]int, len(g.Nodes))
×
104
        sigma[s] = 1
×
105

×
106
        // dist[t] holds the distance between s and t for each node t.
×
107
        // We initialize this to -1 (meaning infinity) for each t != s.
×
108
        dist := make([]int, len(g.Nodes))
×
109
        for i := range dist {
×
110
                dist[i] = -1
×
111
        }
×
112

113
        dist[s] = 0
×
114

×
115
        var (
×
116
                st stack
×
117
                q  queue
×
118
        )
×
119
        q.push(s)
×
120

×
121
        // BFS to calculate the shortest paths (sigma and pred)
×
122
        // from s to t for each node t.
×
123
        for !q.empty() {
×
124
                v := q.front()
×
125
                q.pop()
×
126
                st.push(v)
×
127

×
128
                for _, w := range g.Adj[v] {
×
129
                        // If distance from s to w is infinity (-1)
×
130
                        // then set it and enqueue w.
×
131
                        if dist[w] < 0 {
×
132
                                dist[w] = dist[v] + 1
×
133
                                q.push(w)
×
134
                        }
×
135

136
                        // If w is on a shortest path the update
137
                        // sigma and add v to w's predecessor list.
138
                        if dist[w] == dist[v]+1 {
×
139
                                sigma[w] += sigma[v]
×
140
                                pred[w] = append(pred[w], v)
×
141
                        }
×
142
                }
143
        }
144

145
        // delta[v] is the ratio of the shortest paths between s and t that go
146
        // through v and the total number of shortest paths between s and t.
147
        // If we have delta then the betweenness centrality is simply the sum
148
        // of delta[w] for each w != s.
149
        delta := make([]float64, len(g.Nodes))
×
150

×
151
        for !st.empty() {
×
152
                w := st.top()
×
153
                st.pop()
×
154

×
155
                // pred[w] is the list of nodes that immediately precede w on a
×
156
                // shortest path from s.
×
157
                for _, v := range pred[w] {
×
158
                        // Update delta using Brandes' equation.
×
159
                        delta[v] += (float64(sigma[v]) / float64(sigma[w])) * (1.0 + delta[w])
×
160
                }
×
161

162
                if w != s {
×
163
                        // As noted above centrality is simply the sum
×
164
                        // of delta[w] for each w != s.
×
165
                        centrality[w] += delta[w]
×
166
                }
×
167
        }
168
}
169

170
// Refresh recalculates and stores centrality values.
171
func (bc *BetweennessCentrality) Refresh(graph ChannelGraph) error {
×
172
        cache, err := NewSimpleGraph(graph)
×
173
        if err != nil {
×
174
                return err
×
175
        }
×
176

177
        var wg sync.WaitGroup
×
178
        work := make(chan int)
×
179
        partials := make(chan []float64, bc.workers)
×
180

×
181
        // Each worker will compute a partial result.
×
182
        // This partial result is a sum of centrality updates
×
183
        // on roughly N / workers nodes.
×
184
        worker := func() {
×
185
                defer wg.Done()
×
186
                partial := make([]float64, len(cache.Nodes))
×
187

×
188
                // Consume the next node, update centrality
×
189
                // parital to avoid unnecessary synchronization.
×
190
                for node := range work {
×
191
                        betweennessCentrality(cache, node, partial)
×
192
                }
×
193
                partials <- partial
×
194
        }
195

196
        // Now start the N workers.
197
        wg.Add(bc.workers)
×
198
        for i := 0; i < bc.workers; i++ {
×
199
                go worker()
×
200
        }
×
201

202
        // Distribute work amongst workers.
203
        // Should be fair when the graph is sufficiently large.
204
        for node := range cache.Nodes {
×
205
                work <- node
×
206
        }
×
207

208
        close(work)
×
209
        wg.Wait()
×
210
        close(partials)
×
211

×
212
        // Collect and sum partials for final result.
×
213
        centrality := make([]float64, len(cache.Nodes))
×
214
        for partial := range partials {
×
215
                for i := 0; i < len(partial); i++ {
×
216
                        centrality[i] += partial[i]
×
217
                }
×
218
        }
219

220
        // Get min/max to be able to normalize
221
        // centrality values between 0 and 1.
222
        bc.min = 0
×
223
        bc.max = 0
×
224
        if len(centrality) > 0 {
×
225
                for _, v := range centrality {
×
226
                        if v < bc.min {
×
227
                                bc.min = v
×
228
                        } else if v > bc.max {
×
229
                                bc.max = v
×
230
                        }
×
231
                }
232
        }
233

234
        // Divide by two as this is an undirected graph.
235
        bc.min /= 2.0
×
236
        bc.max /= 2.0
×
237

×
238
        bc.centrality = make(map[NodeID]float64)
×
239
        for u, value := range centrality {
×
240
                // Divide by two as this is an undirected graph.
×
241
                bc.centrality[cache.Nodes[u]] = value / 2.0
×
242
        }
×
243

244
        return nil
×
245
}
246

247
// GetMetric returns the current centrality values for each node indexed
248
// by node id.
249
func (bc *BetweennessCentrality) GetMetric(normalize bool) map[NodeID]float64 {
×
250
        // Normalization factor.
×
251
        var z float64
×
252
        if (bc.max - bc.min) > 0 {
×
253
                z = 1.0 / (bc.max - bc.min)
×
254
        }
×
255

256
        centrality := make(map[NodeID]float64)
×
257
        for k, v := range bc.centrality {
×
258
                if normalize {
×
259
                        v = (v - bc.min) * z
×
260
                }
×
261
                centrality[k] = v
×
262
        }
263

264
        return centrality
×
265
}
STATUS · Troubleshooting · Open an Issue · Sales · Support · CAREERS · ENTERPRISE · START FREE · SCHEDULE DEMO
ANNOUNCEMENTS · TWITTER · TOS & SLA · Supported CI Services · What's a CI service? · Automated Testing

© 2025 Coveralls, Inc