growthmodels (version 1.3.1)

logistic: Logistic growth model

Description

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

Usage

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

Arguments

t

time

alpha

upper asymptote

beta

growth range

k

growth rate

x

size

Author

Daniel Rodriguez

References

D. Fekedulegn, M. Mac Siurtain, and J. Colbert, "Parameter estimation of nonlinear growth models in forestry," Silva Fennica, vol. 33, no. 4, pp. 327-336, 1999.

Examples

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

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