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# last modified 2011-08-06 by J. Fox
fscores <- function(model, ...){
UseMethod("fscores")
}
fscores.sem <- function(model, data=model$data, center=TRUE, scale=FALSE, ...){
m <- model$m
P <- model$P
A <- model$A
var.names <- model$var.names
observed <- var.names %in% rownames(model$C)
if (all(observed)) stop("there are no latent variables")
IAinv <- solve(diag(m) - A)
Sigma <- IAinv %*% P %*% t(IAinv)
B <- solve(Sigma[observed, observed]) %*% Sigma[observed, !observed]
rownames(B) <- var.names[observed]
colnames(B) <- var.names[!observed]
if (is.null(data)) return(B)
X <- as.matrix(data[,var.names[observed]])
if (center || scale) X <- scale(X, center=center, scale=scale)
X %*% B
}
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