  We present an alternative method for calculating likelihoods in molecular
phylogenetics. Our method is based on partial likelihood tensors, which are
generalizations of partial likelihood vectors, as used in Felsenstein's
approach. Exploiting a lexicographic sorting and partial likelihood tensors, it
is possible to obtain significant computational savings. We show this on a
range of simulated data by enumerating all numerical calculations that are
required by our method and the standard approach.
