R: Representational Markov equivalence to bidirected graphs.

RepMarBG {ggm} | R Documentation

## 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).

### Details

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

### 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.

### Author(s)

Kayvan Sadeghi

### References

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

### See Also

`MarkEqMag`, `MarkEqRcg`, `RepMarDAG`, `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)

[Package ggm version 2.3 Index]