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 \(X_{t+1} = K^{1-S} X_{t}^S \epsilon_{t}\), 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, ricker, and the tutorials at https://kingaa.github.io/pomp.

Examples

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