logist_first_deriv_ft: First derivative of the logistic model function for the...

In unkyunglee/HDChangePoint: Estimating disease onset from change points of markers measured with error

Description

First derivative of the logistic model function for the parametric nonlinear mixed effects model (nlme) procedure

Usage

logist_first_deriv_ft(theta1, theta2, theta3, logage)

Arguments

theta1	a scale parameter, which determines steepness of the logistic model.
theta2	a parameter for an inflection point.
theta3	a parameter, which determines the maximum (asymptote) of the logistic model.
logage	a vector of time points (log-scaled ages), which is generated around theta2. It can be an any length of numeric vector.

Value

a vector of the first derivative of the logistic function with respect to (logage-theta2).

Examples

library(HDChangePoint)

## Specify parameters
theta1=6;
theta2=0;
theta3=1;


## Specify the time points (log-scaled ages)
logage<-seq(-0.5, 0.5, by=0.1)

## Obtain a vector of the first derivative of the logistic model
logit_first_derv<-logist_first_deriv_ft(6, 0, 1,  logage);

## Plot the first derivative of the arctangent model
plot(logage, logit_first_derv, type='l')

unkyunglee/HDChangePoint documentation built on Nov. 27, 2021, 2:57 p.m.