| Check whether a directed graph is acyclic {MXM} | R Documentation |
Check whether a directed graph is acyclic
Description
Check whether a directed graph is acyclic.
Usage
is.dag(dag)
Arguments
dag |
A square matrix representing a directed graph which contains either 0, 1 or 0, 2, and 3. In the first canse where G[i, j] = 1, means there is an arrow from node i to node j. In the second case G[i, j] = 2 and G[j, i] = 3 means that there is an arrow from node i to node j, where the 2 iindcates the arrohead and the 3 inducates the arrowtail. |
Details
The topological sort is performed. If it cannot be performed, NAs are returned. Hence, the functions checks for NAs.
Value
A logical value, TRUE if the matrix represents a DAG and FALSE otherwise.
Author(s)
Michail Tsagris
R implementation and documentation: Michail Tsagris mtsagris@uoc.gr
References
Chickering, D.M. (1995). A transformational characterization of equivalent Bayesian network structures. Proceedings of the 11th Conference on Uncertainty in Artificial Intelligence, Montreal, Canada, 87-98.
See Also
topological_sort, dag2eg, pc.or
Examples
# simulate a dataset with continuous data
# simulate a dataset with continuous data
G <- rdag(100, 20, 0.3)$G
is.dag(G) ## TRUE