Topological sort of a DAG {Rfast}

Topological sort of a DAG

Description

Topological sort of a DAG.

Usage

topological_sort(dag)

Arguments

dag

A square matrix representing a directed graph which contains 0s and 1s. If G[i, j] = 1 it means there is an arrow from node i to node j. When there is no edge between nodes i and j if G[i, j] = 0.

Details

The function is an R translation from an old matlab code.

Value

A vector with numbers indicating the sorting. If the dag is not a Directed acyclic Graph, NA will be returned.

Author(s)

Michail Tsagris and Manos Papadakis

R implementation and documentation: Michail Tsagris <[e-mail]> and Manos Papadakis <[e-mail]>

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

floyd, pc.skel

Examples

G <- matrix(0, 5, 5)
G[2, 1] <- 1
G[3, 1] <- 1
G[4, 2] <- 1
G[5, 4] <- 1
res<-topological_sort(G)
G[2, 4] <- 1
res<-topological_sort(G)