grofit (version 1.1.1-1)

initgompertz.exp: Function to generate initial values for parameter estimation

Description

The function receives time points, growth data, values for $A$, $\mu$ and $\lambda$ and returns a list object which entrys are used as initial values in the nonlinear fit procedure nls. In this case the function is serve to define initial values for scaling parameter $\alpha$ and shifting parameter $t_{shift}$

Usage

initgompertz.exp(time, y, A, mu, lambda)

Arguments

time

Time points.

y

Growth data.

A

Maximum of the curve. If a vector is provided only the first entry is used.

mu

Maximum slope. If a vector is provided only the first entry is used.

lambda

Lag-phase. If a vector is provided only the first entry is used.

Value

A

Maximum of the curve.

mu

Maximum slope.

lambda

Lag-phase.

addpar

Two element vector defining scaling parameter $\alpha$ and shifting parameter $t_{shift}$.

See Also

gompertz.exp, gcFitModel