This returns a numeric matrix instead of character matrix
# S3 method for nlmixrNlme
VarCorr(x, sigma = NULL, ...)a fitted model object, usually an object inheriting from
class "lme".
an optional numeric value used as a multiplier for the
standard deviations. The default is x$sigma or 1
depending on class(x).
further optional arguments passed to other methods (none for the methods documented here).
Extract the VarCorr from the nlmixr nlme object