Class of objects that characterize the error distribution of a regression-scale model.
This class of objects is returned by a call to a family.rsm
generator function. See rsm.families for the
distributions which are supported by the marg package. The
object includes a list of functions and expressions that
characterize the error distribution of a regression-scale model.
These are used by the IRLS algorithm implemented in the
rsm fitting routine. New families can be added to the
ones already supported. See the demonstration file
margdemo.R that ships with the package. There is a
print method for family.rsm objects which
produces a simple summary without any detail; use
unclass(family.rsm.object) to see the contents.
The following components, with the corresponding functionality,
are required for a family.rsm object:
familya character vector giving the family name.
g0a function that yields minus the log density of the error distribution in the regression-scale model.
g1a function that yields the first derivative of minus the log density.
g2a function that yields the second derivative of minus the log density.
dfargument with NULL value; must be included to guarantee
compatibility with the existing code.
kargument with NULL value; must be included to guarantee
compatibility with the existing code.