An implementation of the Likelihood ratio Test (LRT) for testing that,
in a (non)linear mixed effects model, the variances of a subset of the random
effects are equal to zero. There is no restriction on the subset of variances
that can be tested: for example, it is possible to test that all the variances
are equal to zero. Note that the implemented test is asymptotic.
This package should be used on model fits from packages 'nlme', 'lmer', and 'saemix'.
Charlotte Baey, Paul-Henry Cournède and Estelle Kuhn (2019)