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, 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
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.