transfquad: Variance to standard deviation transform.
Description
This function compute the standard deviation of an output from a parameteric nonlinear variance function object, usualy stored as nl.form. The gradient and hessian attributes also will be transformed.
transfquadvec transform a vector similarly.
Usage
transfquad(varcomp)
Arguments
varcomp
Is vector of variances, with (n by p) "gradient" and (three dimentional n by p by p) "hessian" attributes.
Value
Vector of transformed standard deviation, including (n by p) "gradient" and (three dimentional n by p by p) "hessian" attributes.
Details
The standard deviation is simply square root of variance. The gradinet is transformed of square root of gradient. Hessian is transformed of second derivative of square root function as well.
References
Riazoshams H, Midi H, and Ghilagaber G, 2018,. Robust Nonlinear Regression, with
Application using R, Joh Wiley and Sons.