ggm (version 0.5)

Simple Graph Operations: Simple graph operations

Description

Finds the boundary, children, parents of a subset of nodes of a graph.

Usage

bd(nn, A)
ch(nn, A)
pa(nn, A)

Arguments

nn

a vector of nodes. It may either a numeric vector, or a character vector. If it is character vector must be a subset of the rownames of the edge matrix.

A

a square matrix specifying the edge matrix of the graph

Value

• A vector, specifying the boundary or the children or the parents of nodes nn in the graph. This is a numeric or a character vector depending on the mode of nn.

Details

For the definitions of these operators see Lauritzen (1996).

References

Lauritzen, S. (1996). Graphical models. Oxford: Clarendon Press.

See Also

UG, DAG

Examples

## find boundary of a subset of nodes of a DAG
G <- DAG(y ~ x+b+a, b~a, x~a)
bd("b", G)
bd(c("b", "x"), G)
bd(2, G)
bd(c(2,3), G)
## find boundary of a subset of nodes of an UG
G <- UG(~ y*x*z + z*h*v)
bd("z", G)
bd(c("y", "x"), G)
bd(5, G)
bd(c(2,5), G)
## children of a subset of nodes of a DAG
G <- DAG(y ~ x+b+a, b~a, x~a)
ch("b", G)
ch(c("b", "x"), G)
ch(2, G)
ch(c(2,3), G)
## parents of a subset of nodes of a DAG
pa("b", G)
pa(c("b", "x"), G)
pa(2, G)
pa(c(2,3), G)