pwSEM (version 1.0.0)

basiSet.MAG: basiSet.MAG

Description

Gets the union basis set of a MAG (mixed acyclic graph) involving either directed edges (X->Y) if X is a direct cause of Y or bi-directed edges (X<->Y) if X is not a cause of Y, Y is not a cause of X, but both X and Y share a common latent cause. It is easiest to create the MAG using the DAG() function of the ggm library and then modifying the binary output matrix by adding a value of 100 for each pair (row & column) of variables with a bi-directed edge.

Usage

basiSet.MAG(cgraph)

Value

A list containing the m-separation claims in the union basis set

Arguments

cgraph

The adjacency matrix of the MAG, i.e. a square Boolean matrix of order equal to the number of nodes of the graph and with (1) a one in position (i,j) if there is an arrow from i to j; (2) a 100 in positions (i,j) and (j,i) if there is a double-headed arrow betweein i and j; (3) otherwise a zero in position (i,j) The rownames of the adjacency matrix are the nodes of the MAG.

Examples

# W->X->Y->Z and X<->Z
# Create the DAG skeleton
mag<-ggm::DAG(X~W,Y~X,Z~Y)
# Add the dependent error
mag[2,3]<-mag[3,2]<-100
basiSet.MAG(mag)