pomp (version 1.10)

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 $X[t+1]=K^(1-S) X[t]^S eps[t]$, where $S=e^{-r}$ and the $eps[t]$ are i.i.d. lognormal random deviates with variance $sigma^2$. The observed variables $Y_t$ are distributed as $lognormal(log(X[t]),tau)$. 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

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