Apparently Analagous Threads
- degrees of freedom (lme4 and nlme)
- nlme package, fixing variance.covariance matrix of residuals
- Extracting variance-covariance matrix from nlme object
- Accessing the fixed- and random-effects variance-covariance matrices of an nlme model
- Function nlme::lme in Ubuntu (but not Win or OS X): "Non-positive definite approximate variance-covariance"