DG {ggm} | R Documentation |
Directed graphs
Description
Defines the adjacency of a directed graph.
Usage
DG(...)
Arguments
... |
a sequence of model formulae |
Details
The directed graph is defined by a sequence of models formulae. For each formula the response defines a node of the graph and its parents. The graph contains no loops.
Value
the adjacency matrix of the directed graph, i.e.,
a square Boolean matrix of order equal to the number of nodes of the
graph and a one in position if there is an arrow from
to
and zero otherwise. The dimnames of the adjacency
matrix are the labels for the nodes of the graph.
Author(s)
G. M. Marchetti
References
Lauritzen, S. (1996). Graphical models. Oxford: Clarendon Press.
See Also
Examples
## A DAG
DG(y ~ x, x ~ z, z ~ u)
## A cyclic directed graph
DG(y ~ x, x ~ z, z ~ y)
## A graph with two arrows between two nodes
DG(y ~ x, x ~ y)
## There can be isolated nodes
DG(y ~ x, x ~ x)
[Package ggm version 2.5.1 Index]