context("layout_with_mds") test_that("layout_with_mds works", { library(igraph) ## A tree g <- make_tree(10, 2, "undirected") mymds <- function(g) { sp <- distances(g) sp <- sp * sp sp <- sp - rowMeans(sp) - rep(rowMeans(sp), each=nrow(sp)) + mean(sp) sp <- sp / -2 ei <- eigen(sp) va <- sqrt(abs(ei$values[1:2])) ei$vectors[,1:2] * rep(va, each=nrow(sp)) } expect_that(mymds(g), equals(layout_with_mds(g))) ## plot(g, layout=ll) ## A graph with multiple components, just test that it runs set.seed(42) g <- make_ring(10) + make_ring(3) expect_that(ncol(layout_with_mds(g)), equals(2)) ## Small stress test for (i in 1:10) { g <- sample_gnp(100, 2/100) l <- layout_with_mds(g) expect_that(ncol(l), equals(2)) } })
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