R: Representational Markov equivalence to undirected graphs.

RepMarUG {ggm} | R Documentation

## Representational Markov equivalence to undirected graphs.

### Description

`RepMarUG` determines whether a given maximal ancestral graph can be Markov equivalent to an undirected graph, and if that is the case, it finds an undirected graph that is Markov equivalent to the given graph.

### Usage

    RepMarUG(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 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`, `RepMarBG`, `RepMarDAG`

### Examples

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

[Package ggm version 2.3 Index]