optimx (>= 2013.8.6), mgcv, numDeriv, Rsolnp
optimx (>= 2013.8.6), mgcv, methods, numDeriv, Rsolnp
optimx (>= 2013.8.6), mgcv, methods, numDeriv, nloptr, Rsolnp
testthat, covr, knitr, rmarkdown, bookdown