growthmodels (version 1.3.1)

loglogistic: Log-logistic growth model

Description

Computes the Log-logistic growth model $$ y(t) = \frac{\alpha}{1 + \beta exp(-k log(t)}$$

Usage

loglogistic(t, alpha, beta, k)
loglogistic.inverse(x, alpha, beta, k)

Arguments

t

time

alpha

upper asymptote

beta

growth range

k

growth rate

x

size

Author

Daniel Rodriguez

References

A. Khamiz, Z. Ismail, and A. T. Muhammad, "Nonlinear growth models for modeling oil palm yield growth," Journal of Mathematics and Statistics, vol. 1, no. 3, p. 225, 2005.

Examples

growth <- loglogistic(0:10, 10, 0.5, 0.3)

# Calculate inverse function
time <- loglogistic.inverse(growth, 10, 0.5, 0.3)