tests/testthat/test-graph.subisomorphic.lad.R

In igraph: Network Analysis and Visualization

test_that("graph.subisomorphic, method = 'lad' works", {
  pattern <- graph_from_literal(
    1:2:3:4:5,
    1 - 2:5, 2 - 1:5:3, 3 - 2:4, 4 - 3:5, 5 - 4:2:1
  )
  target <- graph_from_literal(
    1:2:3:4:5:6:7:8:9,
    1 - 2:5:7, 2 - 1:5:3, 3 - 2:4, 4 - 3:5:6:8:9,
    5 - 1:2:4:6:7, 6 - 7:5:4:9, 7 - 1:5:6,
    8 - 4:9, 9 - 6:4:8
  )
  domains <- list(
    `1` = c(1, 3, 9), `2` = c(5, 6, 7, 8), `3` = c(2, 4, 6, 7, 8, 9),
    `4` = c(1, 3, 9), `5` = c(2, 4, 8, 9)
  )
  i1 <- subgraph_isomorphic(pattern, target, method = "lad")
  i2 <- subgraph_isomorphic(pattern, target, induced = TRUE, method = "lad")
  i3 <- subgraph_isomorphic(pattern, target,
    domains = domains,
    method = "lad"
  )

  expect_true(i1)
  expect_true(i2)
  expect_true(i3)
})

test_that("LAD stress test", {
  local_rng_version("3.5.0")
  set.seed(42)
  N <- 100

  for (i in 1:N) {
    target <- sample_gnp(20, .5)
    pn <- sample(4:18, 1)
    pattern <- induced_subgraph(target, sample(vcount(target), pn))
    iso <- subgraph_isomorphic(pattern, target,
      induced = TRUE,
      method = "lad"
    )
    expect_true(iso)
  }

  set.seed(42)

  for (i in 1:N) {
    target <- sample_gnp(20, 1 / 20)
    pn <- sample(5:18, 1)
    pattern <- sample_gnp(pn, .6)
    iso <- subgraph_isomorphic(pattern, target,
      induced = TRUE,
      method = "lad"
    )
    expect_false(iso)
  }
})