gompertz_fn {drda}R Documentation

Gompertz function

Description

Evaluate at a particular set of parameters the Gompertz function.

Usage

gompertz_fn(x, theta)

Arguments

x

numeric vector at which the Gompertz function is to be evaluated.

theta

numeric vector with the four parameters in the form c(alpha, beta, eta, phi).

Details

The Gompertz function ⁠f(x; theta)⁠ is defined here as

⁠alpha + (beta - alpha) exp(-exp(-eta * (x - phi)))⁠

where theta = c(alpha, beta, eta, phi), alpha is the lower horizontal asymptote, beta > alpha is the upper horizontal asymptote, eta is the steepness of the curve or growth rate, and phi related to the function value at x = 0.

Value

Numeric vector of the same length of x with the values of the Gompertz function.


[Package drda version 1.0.0 Index]