ggm (version 2.5)

isADMG: Acyclic directed mixed graphs

Description

Check if it is an adjacency matrix of an ADMG

Usage

isADMG(amat)

Value

A logical value, TRUE if it is an ancestral graph and FALSE

otherwise.

Arguments

amat

Author

Giovanni M. Marchetti, Mathias Drton

Details

Checks if the following conditions must hold: (i) no undirected edge meets an arrowhead; (ii) no directed cycles;

References

Richardson, T. S. and Spirtes, P. (2002). Ancestral Graph Markov Models. Annals of Statistics, 30(4), 962--1030.

See Also

makeMG, isADMG

Examples

	## Examples from Richardson and Spirtes (2002)
	a1 <- makeMG(dg=DAG(a~b, b~d, d~c), bg=UG(~a*c))  
	isADMG(a1)    # Not an AG. (a2) p.969    
	a2 <- makeMG(dg=DAG(b ~ a, d~c), bg=UG(~a*c+c*b+b*d))           # Fig. 3 (b1) p.969  
	isADMG(a2)