separates {RBGL}R Documentation

A function to test whether a subset of nodes separates two other subsets of nodes.

Description

The function tests to see whether a set of nodes, S1, separates all nodes in a from all nodes in a.

Usage

separates(a, b, S1, g)

Arguments

a The names of the nodes in the from set.
b The names of the nodes in the to set.
S1 The names of the nodes in the separation set.
g An instance of the graph class. All nodes named in the other arguments must be nodes of this graph.

Details

The algorithm is quite simple. A subgraph is created by removing the nodes named in S1 from g. Then all paths between elements of a to elements of b are tested for. If any path exists the function returns FALSE, otherwise it returns TRUE.

Value

Either TRUE or FALSE depending on whether S1 separates a from b in g1.

Author(s)

R. Gentleman

References

S. Lauritzen, Graphical Models, OUP.

See Also

johnson.all.pairs.sp

Examples

  km <- fromGXL(file(system.file("XML/kmstEx.gxl",package="RBGL")))
  separates("B", "A", "E", km)
  separates("B", "A", "C", km)

[Package RBGL version 1.10.0 Index]