psi_func-class: Class of "Psi Functions" for M-Estimation
Description
The class "psi_func" is used to store $\psi \ (psi)$
functions for M-estimation. In particular, an object of the class
contains $\rho(x) \ (\code{rho})$, its derivative
$\psi(x) \ (psi)$, the weight function $\psi(x)/x$, and
first derivative of $\psi$, Dpsi = $\psi'(x)$.
Arguments
Objects from the Class
Objects can be created by calls of the form new("psi_func", ...),
but preferably by psiFunc(...).
Methods
No methods defined with class "psi_func" in the signature.