arctan_second_deriv_ft: Second derivative of the arctangent model function for the...

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

Description

Second derivative of the arctangent model function for the parametric nonlinear mixed effects model (nlme) procedure

Usage

arctan_second_deriv_ft(gam1, gam2, gam3, logage)

Arguments

gam1	a scale parameter.
gam2	a parameter for an inflection point.
gam3	a parameter, which determines steepness of the arctangent model.
logage	a vector of time points (log-scaled ages), which is generated around gam2. It can be an any length of numeric vector.

Value

a vector of the second derivative of the arctangent function with respect to (logage-gam2).

Examples

library(HDChangePoint)

## Specify parameters
gam1=2.45/pi
gam2=0
gam3=pi/1.1

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

## Obtain a vector of the second derivative of the arctangent model
arct_sec_derv<-arctan_second_deriv_ft(gam1=2.45/pi, gam2=0, gam3=pi/1.1, logage=logage)

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

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