ggm (version 2.2)

RepMarDAG: Representational Markov equivalence to directed acyclic graphs.

Description

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

Usage

RepMarDAG(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, nod

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

RepMarDAG first looks whether the subgraph induced by full lines is chordal and whether there is a minimal collider path or cycle of length 4 in graph.

References

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

See Also

MarkEqMag, MarkEqRcg, RepMarBG, RepMarUG

Examples

H<-matrix(c(0,10,0,0,10,0,0,0,0,1,0,100,0,0,100,0),4,4)
RepMarBG(H)