logistic6_fn {drda}R Documentation

6-parameter logistic function

Description

Evaluate at a particular set of parameters the 6-parameter logistic function.

Usage

logistic6_fn(x, theta)

Arguments

x

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

theta

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

Details

The 6-parameter logistic function ⁠f(x; theta)⁠ is defined here as

alpha + (beta - alpha) / (xi + nu * exp(-eta * (x - phi)))^(1 / nu)

where theta = c(alpha, beta, eta, phi, nu, xi), beta > alpha, xi > 0, and nu > 0.

Value

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


[Package drda version 1.0.0 Index]