G-identifiability of an UG
Tests if an undirected graph is G-identifiable.
isGident(amat)
amat |
a symmetric matrix with dimnames representing the adjacency matrix of an undirected graph |
An undirected graph is said G-identifiable if every connected component of the complementary graph contains an odd cycle (Stanghellini and Wermuth, 2005). See also Tarantola and Vicard (2002).
a logical value, TRUE if the graph is G-identifiable and
FALSE if it is not.
Giovanni M. Marchetti
Stanghellini, E. \& Wermuth, N. (2005). On the identification of path-analysis models with one hidden variable. Biometrika, 92(2), 337-350.
Stanghellini, E. (1997). Identification of a single-factor model using graphical Gaussian rules. Biometrika, 84, 241–244.
Tarantola, C. \& Vicard, P. (2002). Spanning trees and identifiability of a single-factor model. Statistical Methods \& Applications, 11, 139–152.
Vicard, P. (2000). On the identification of a single-factor model with correlated residuals. Biometrika, 87, 199–205.
## A not G-identifiable UG G1 <- UG(~ a*b + u*v) isGident(G1) ## G-identifiable UG G2 <- UG(~ a + b + u*v) isGident(G2) ## G-identifiable UG G3 <- cmpGraph(UG(~a*b*c+x*y*z)) isGident(G3)
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