context("betweenness")
test_that("betweenness works for kite graph", {
library(igraph)
kite <- graph_from_literal(Andre - Beverly:Carol:Diane:Fernando,
Beverly - Andre:Diane:Ed:Garth,
Carol - Andre:Diane:Fernando,
Diane - Andre:Beverly:Carol:Ed:Fernando:Garth,
Ed - Beverly:Diane:Garth,
Fernando - Andre:Carol:Diane:Garth:Heather,
Garth - Beverly:Diane:Ed:Fernando:Heather,
Heather - Fernando:Garth:Ike,
Ike - Heather:Jane,
Jane - Ike)
nf <- (vcount(kite)-1) * (vcount(kite)-2) /2
bet <- structure(betweenness(kite) / nf, names=V(kite)$name)
bet <- round(sort(bet, decreasing=TRUE), 3)
expect_that(bet, equals(structure(c(0.389, 0.231, 0.231, 0.222, 0.102,
0.023, 0.023, 0.000, 0.000, 0.000),
names=c("Heather", "Fernando",
"Garth", "Ike", "Diane", "Andre",
"Beverly", "Carol", "Ed", "Jane"))))
bet2 <- structure(betweenness(kite, normalized=TRUE), names=V(kite)$name)
bet2 <- round(sort(bet2, decreasing=TRUE), 3)
expect_that(bet2, equals(bet))
})
test_that("weighted betweenness works", {
library(igraph)
nontriv <- graph( c(0,19,0,16,0,20,1,19,2,5,3,7,3,8,
4,15,4,11,5,8,5,19,6,7,6,10,6,8,
6,9,7,20,9,10,9,20,10,19,
11,12,11,20,12,15,13,15,
14,18,14,16,14,17,15,16,17,18)+1, dir=FALSE )
E(nontriv)$weight <- c(0.5249, 1, 0.1934, 0.6274, 0.5249,
0.0029, 0.3831, 0.05, 0.6274, 0.3831,
0.5249, 0.0587, 0.0579, 0.0562, 0.0562,
0.1934, 0.6274, 0.6274, 0.6274, 0.0418,
0.6274, 0.3511, 0.3511, 0.1486, 1, 1,
0.0711, 0.2409)
nontrivRes <- c(20,0,0,0,0,19,80,85,32,0,10,
75,70,0,36,81,60,0,19,19,86)
bet <- betweenness(nontriv)
expect_that(bet, equals(nontrivRes))
})
test_that("normalization works well", {
library(igraph)
g1 <- graph_from_literal( 0 +-+ 1 +-+ 2 )
b11 <- betweenness(g1, normalized=TRUE, directed=FALSE)
expect_that(b11, equals(c('0'=0, '1'=1, '2'=0)))
b12 <- betweenness(g1, normalized=TRUE, directed=TRUE)
expect_that(b12, equals(c('0'=0, '1'=1, '2'=0)))
g2 <- graph_from_literal( 0 --- 1 --- 2 )
b2 <- betweenness(g2, normalized=TRUE)
expect_that(b2, equals(c('0'=0, '1'=1, '2'=0)))
})
test_that("shortest paths are compared with tolerance when calculating betweenness", {
# The test case below is designed in a way that the paths 3-6 and 3-4-6 have the
# same total weight when compared with a tolerance, but they appear different
# if the comparison is made without an epsilon tolerance due to numeric
# inaccuracies.
#
# See https://github.com/igraph/rigraph/issues/314
from <- c(1, 2, 3, 3, 3, 4, 6, 7, 2, 9, 5, 7, 9, 9, 5, 8)
to <- c(4, 3, 6, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
edges <- cbind(from, to)
edges.dists <- c(1.9617537, 0.9060834, 2.2165446, 1.6251956,
2.4473929, 0.5913490, 8.7093236, 2.8387330,
6.1225042, 20.7217776, 6.8027218, 16.3147479,
5.2605598, 6.6816853, 4.9482123, 1.8989790)
g <- graph.data.frame(edges, directed = FALSE)
result <- betweenness(g, weights = edges.dists)
expect_that(result[1:5], equals(c('1'=0, '2'=44, '3'=71, '4'=36.5, '6'=44)))
})
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