context("knn")
test_that("knn works", {
library(igraph)
set.seed(42)
## Some trivial ones
g <- make_ring(10)
expect_that(knn(g), equals(list(knn=rep(2,10), knnk=c(NaN, 2))))
g2 <- make_star(10)
expect_that(knn(g2), equals(list(knn=c(1, rep(9,9)),
knnk=c(9, rep(NaN, 7), 1))))
## A scale-free one, try to plot 'knnk'
g3 <- simplify(sample_pa(1000, m=5))
r3 <- knn(g3)
expect_that(r3$knn[43], equals(46))
expect_that(r3$knn[1000], equals(192.4))
expect_that(r3$knnk[100], equals(18.78))
expect_that(length(r3$knnk), equals(359))
## A random graph
g4 <- sample_gnp(1000, p=5/1000)
r4 <- knn(g4)
expect_that(r4$knn[1000], equals(20/3))
expect_that(length(r4$knnk), equals(15))
expect_that(r4$knnk[12], equals(19/3))
## A weighted graph
g5 <- make_star(10)
E(g5)$weight <- seq(ecount(g5))
r5 <- knn(g5)
expect_that(r5, equals(structure(list(knn = c(1, rep(9, 9)), knnk =
c(9, NaN, NaN,
NaN, NaN, NaN, NaN, NaN,
1)), .Names = c("knn",
"knnk")) ))
})
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