deleteZeroComponents {cAIC4} | R Documentation |
Is used in the cAIC
function if method = "steinian"
and
family = "gaussian"
. The function deletes all random effects terms
from the call if corresponding variance parameter is estimated to zero and
updates the model in merMod
.
deleteZeroComponents(m)
m |
An object of class |
Uses the cnms
slot of m
and the relative covariance factors to
rewrite the random effects part of the formula, reduced by those parameters
that have an optimum on the boundary. This is necessary to obtain the true
conditional corrected Akaike information. For the theoretical justification
see Greven and Kneib (2010). The reduced model formula is then updated. The
function deleteZeroComponents is then called iteratively to check if in the
updated model there are relative covariance factors parameters on the
boundary.
An updated object of class merMod
For models called via gamm4
no automated update
is available. Instead a warning with terms to omit from the model is
returned.
Benjamin Saefken bsaefke@uni-goettingen.de \& David Ruegamer
Greven, S. and Kneib T. (2010) On the behaviour of marginal and conditional AIC in linear mixed models. Biometrika 97(4), 773-789.
## Currently no data with variance equal to zero... b <- lmer(Reaction ~ Days + (Days | Subject), sleepstudy) deleteZeroComponents(b)