ggm (version 2.3)

RepMarBG: Representational Markov equivalence to bidirected graphs.

Description

RepMarBG determines whether a given maximal ancestral graph can be Markov equivalent to a bidirected graph, and if that is the case, it finds a bidirected graph that is Markov equivalent to the given graph.

Usage

RepMarBG(amat)

Arguments

amat

An adjacency matrix, or a graph that can be a graphNEL or an igraph object or a vector of length \(3e\), where \(e\) is the number of edges of the graph, that is a sequence of triples (type, node1label, node2label). The type of edge can be "a" (arrows from node1 to node2), "b" (arcs), and "l" (lines).

Value

A list with two components: verify and amat. verify is a logical value, TRUE if there is a representational Markov equivalence and FALSE otherwise. amat is either NA if verify == FALSE or the adjacency matrix of the generated graph, if verify == TRUE. In this case it consists of 4 different integers as an \(ij\)-element: 0 for a missing edge between \(i\) and \(j\), 1 for an arrow from \(i\) to \(j\), 10 for a full line between \(i\) and \(j\), and 100 for a bi-directed arrow between \(i\) and \(j\). These numbers are added to be associated with multiple edges of different types. The matrix is symmetric w.r.t full lines and bi-directed arrows.

Details

RepMarBG looks for presence of an unshielded non-collider V-configuration in graph.

References

Sadeghi, K. (2011). Markov equivalences for subclasses of loopless mixed graphs. Submitted, 2011.

See Also

MarkEqMag, MarkEqRcg, RepMarDAG, RepMarUG

Examples

# NOT RUN {
H<-matrix(c(0,10,0,0,10,0,0,0,0,1,0,100,0,0,100,0),4,4)
RepMarBG(H)
# }