MXM (version 0.9.5)

Transformation of a DAG into an essential graph: Transforms a DAG into an essential graph

Description

Transforms a DAG into an essential graph.

Usage

dag2eg(dag, type = NULL)

Arguments

dag

The graph matrix as produced from pc.or or any other algorithm which produces directed graphs. A DAG in general.

type

This can be either NULL or 1 or 2. type = 1 means that the matrix contains 0, 1, 2, 3 where G[i, j] = g[j, i] = 0, means there is no edge between nodes i and j, G[i, j] = g[j, i] = 1, there is an edge between nodes i and j and G[i, j] = 2 and G[j, i] = 3 means that there is an arrow from node i to node j. If type 2, the matrix contains 0 for no edge and 1 for a directed edge. In this case, G[i,j]=1 and G[j,i]=0 means that there is an arrow from node i to node j. If you are not sure of what you have, just leave it NULL, the function will check to which case your matrix belongs.

Value

The matrix of the essential graph.

Details

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

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

plota, nei, pc.or

Examples

# simulate a dataset with continuous data
# simulate a dataset with continuous data
y = rdag(1000, 10, 0.3)
tru = y$G 
eg = dag2eg(tru)
par( mfrow = c(1, 2) )
plota(tru)
plota(eg)