ggm (version 2.5.1)

Simple Graph Operations: Simple graph operations

Description

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

Usage

bd(nn, amat)
ch(nn, amat)
pa(nn, amat)

Value

The operators return a character 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.

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.

amat

a square matrix with dimnames specifying the adjacency matrix of the graph

Author

Giovanni M. Marchetti

Details

For definitions of the 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("x", G)
bd(c("x","b"), 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("v", G)
bd(c("x","v"), 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("x", G)
ch(c("a","x"), G)
## parents of a subset of nodes of a DAG
pa("b", G)
pa(c("b", "x"), G)
pa("x", G)
pa(c("x","b"), G)