pomp (version 0.45-8)

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 $X_{t+1} = K^{1-S} X_{t}^S \epsilon_{t}$, where $S=e^{-r}$ and the $\epsilon_t$ 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-class and the introductory vignette vignette("intro_to_pomp").

Examples

pompExample(gompertz)
plot(gompertz)
coef(gompertz)
coef(gompertz,transform=TRUE)