  We introduce an R package, PCMBase, to rapidly calculate the likelihood for
multivariate phylogenetic comparative methods. The package is not specific to
particular models but offers the user the functionality to very easily
implement a wide range of models where the transition along a branch is
multivariate normal. We demonstrate the package's possibilities on the now
standard, multitrait Ornstein-Uhlenbeck process as well as the novel
multivariate punctuated equilibrium model. The package can handle trees of
various types (e.g. ultrametric, nonultrametric, polytomies, e.t.c.), as well
as measurement error, missing measurements or non-existing traits for some of
the species in the tree.
