pars
Vector of parameters:
pars[1] corresponds to lambda_M (speciation rate of the main clade)
pars[2] corresponds to mu_M (extinction rate of the main clade)
pars[3] corresponds to K' (maximum number of species or a proxy for it in case of exponential decline in speciation rate)
pars[4] corresponds to lambda_S (speciation rate of the novel subclade)
pars[5] corresponds to mu_S (extinction rate)
pars[6] tinn, the time the shift in rates occurs in the lineage leading to the subclade
ddmodel
Sets the model of diversity-dependence:
ddmodel == 1.3 : linear dependence in speciation rate with parameter K' (= diversity where speciation = 0); ddmodel = 1 will be interpreted as this model
ddmodel == 2.1 : variant of exponential dependence in speciation rate with offset at infinity; ddmodel = 2 will be interpreted as this model
ddmodel == 2.2 : 1/n dependence in speciation rate
ddmodel == 2.3 : exponential dependence in speciation rate with parameter x (= exponent)