Function designed to extract the fixed effects from an
MCMCglmm model object. Can either extract all samples from the
fixed effects posteriors or return the posterior means.
Examples
if (FALSE) { # \dontrun{
# a simple MCMCglmm model
data(PlodiaPO)
m <- MCMCglmm(PO ~ 1, random= ~ FSfamily, data=PlodiaPO, verbose=FALSE)
# only extract average fixed effects
fixef(m, use = "mean")
# histogram of posterior samples of fixed effects
hist(fixef(m))
# matches the mean
rowMeans(fixef(m))
} # }