isAcyclic: Graph queries
In ggm: Graphical Markov Models with Mixed Graphs

Description Usage Arguments Value Author(s) References Examples

Checks if a given graph is acyclic.

1	isAcyclic(amat, method = 2)

`amat`	a square Boolean matrix with dimnames, the adjacency matrix of a graph.
`method`	an integer 1 or 2 specifying the method used. If `method=1` the function calls the function `clusters` in package `igraph` to find the strong components: two nodes v and w are in the same strong component iff there are directed paths from v to w and from w to v. If `method=2` the function uses the `ggm` function `transClos`. Method 1 is faster.

a logical value, TRUE if the graph is acyclic and FALSE otherwise.

David Edwards, Giovanni M. Marchetti

Aho, A.V., Hopcroft, J.E. \& Ullman, J.D. (1983). Data structures and algorithms. Reading: Addison-Wesley.

## A cyclic graph
d <- matrix(0,3,3)
rownames(d) <- colnames(d) <- c("x", "y", "z")
d["x","y"] <- d["y", "z"] <- d["z", "x"] <- 1
## Test if the graph is acyclic
isAcyclic(d)
isAcyclic(d, method = 1)