RG function

Ribbonless graph

RG generates and plots ribbonless graphs (a modification of MC graph to use m-separation) after marginalization and conditioning.

RG(amat,M=c(),C=c(),showmat=TRUE,plot=FALSE, plotfun = plotGraph, ...)

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).
• M: A subset of the node set of a that is going to be marginalized over
• C: Another disjoint subset of the node set of a that is going to be conditioned on.
• showmat: A logical value. TRUE (by default) to print the generated matrix.
• plot: A logical value, FALSE (by default). TRUE to plot the generated graph.
• plotfun: Function to plot the graph when plot == TRUE. Can be plotGraph (the default) or drawGraph.
• ...: Further arguments passed to plotfun.

Returns

A matrix that consists 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.

References

Koster, J.T.A. (2002). Marginalizing and conditioning in graphical models. Bernoulli, 8(6), 817-840.

Sadeghi, K. (2013). Stable mixed graphs. Bernoulli 19(5B), 2330–2358.

Author(s)

Kayvan Sadeghi

See Also

AG,, MRG, SG

Examples

ex <- matrix(c(0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, ##The adjacency matrix of a DAG
                       0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
                       1,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
                       0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
                       0,0,0,1,0,0,0,0,0,0,0,0,0,0,0,0,
                       0,1,0,0,1,0,0,0,0,0,0,0,0,0,0,0,
                       0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
                       0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
                       0,0,0,0,0,0,1,1,0,0,0,0,0,0,0,0,
                       0,0,0,0,0,0,0,1,0,0,0,0,0,0,0,0,
                       0,0,0,0,1,0,1,0,1,1,0,0,0,0,0,0,
                       1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
                       0,0,0,0,0,0,0,0,0,1,0,1,0,0,0,0,
                       0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
                       1,0,0,0,0,0,0,0,0,0,0,0,0,1,0,0,
                       0,0,0,0,0,0,0,0,0,0,0,1,0,1,0,0),16,16, byrow = TRUE)

M<-c(3,5,6,15,16)
C<-c(4,7)
RG(ex,M,C,plot=TRUE)