Missing check for constant rate birth-death process simulation

[pveber]

The special implementation for simulating constant rate birth-death seems wrong for lambda = mu, see the equation here, which evaluates to nan in that case. When I try, I find:

> library(TESS)
> length(tess.sim.taxa.age(n = 1, nTaxa = 5, age = 10, lambda = 2, mu = 1)[[1]]$tip.label)
[1] 5
> length(tess.sim.taxa.age(n = 1, nTaxa = 5, age = 10, lambda = 1, mu = 1)[[1]]$tip.label)
[1] 2  ### EXPECTED 5 ###

It is indeed stated in this reference that the equations assume lambda greater than mu. I guess the implementation should check for this condition and call the general purpose implementation otherwise.