stannard {growthmodels}

Stannard growth model

Description

Computes the Stannard growth model

y(t) = \alpha \left[ 1 + exp(-(\beta + k t)/m) \right]^{-m}

Usage

stannard(t, alpha, beta, k, m)

stannard.inverse(x, alpha, beta, k, m)

Arguments

t

time

alpha

upper asymptote

beta

growth displacement

k

growth rate

m

slope of growth

x

size

Author(s)

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 <- stannard(0:10, 1, .2, .1, .5)

# Calculate inverse function
time <- stannard.inverse(growth, 1, .2, .1, .5)