pomp (version 1.19)

gompertz: Gompertz model with log-normal observations.

Description

gompertz is a pomp object encoding a stochastic Gompertz population model with log-normal measurement error.

Details

The state process is $X_{t+1}=K^{1-S}{X}_t^S{ϵ}_t$, where $S=e^{-r}$ and the ${ϵ}_t$ are i.i.d. lognormal random deviates with variance ${\sigma }^2$. The observed variables $Y_t$ are distributed as $\mathrm{lognormal}(\log X_t,\tau )$. Parameters include the per-capita growth rate $r$, the carrying capacity $K$, the process noise s.d. $\sigma$, the measurement error s.d. $\tau$, and the initial condition $X_0$. The pomp object includes parameter transformations that log-transform the parameters for estimation purposes.

See Also

pomp, ricker, and the tutorials at https://kingaa.github.io/pomp.

Examples

# NOT RUN {
pompExample(gompertz)
plot(gompertz)
coef(gompertz)
coef(gompertz,transform=TRUE)
# }