gompertz_fn {drda}R Documentation

Gompertz function


Evaluate at a particular set of parameters the Gompertz function.


gompertz_fn(x, theta)



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


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


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

⁠g(x; theta) = exp(-exp(-eta * (x - phi)))⁠ ⁠f(x; theta) = alpha + delta g(x; theta)⁠

where theta = c(alpha, delta, eta, phi), alpha is the value of the function when x -> -Inf, delta is the (signed) height of the curve, eta > 0 is the steepness of the curve or growth rate, and phi is related with the value of function at x = 0.

When delta < 0 the curve is monotonically decreasing while it is monotonically increasing for delta > 0.


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

[Package drda version 2.0.3 Index]