Calculate link function and up to one derivative for
families known to the package.
Usage
link(xi, fam, deriv = 0, delta)
Value
a list containing some of the following components:
zeroth
the value of the link function at \(\xi\), a vector
of dimension \(d\), where \(d\)
is the dimension of \(\xi\).
first
the value of the first derivative at \(\xi\), a
\(d \times d\) matrix, where \(d\) is the dimension
of \(\xi\) or a scalar if \(\xi\) is scalar.
Arguments
xi
mean value parameter value, a numeric vector.
fam
an object of class "astfam" produced by one of
the family functions (see families) specifying the
exponential family.
deriv
the number of derivatives wanted. Must be either
zero or one.
delta
direction in which limit is taken. Link
function is for family that is limit of family specified, limit
being for distributions with canonical parameter
\(\theta + s \delta\),
the limit being as \(s \to \infty\). May be missing,
in which case \(\delta = 0\) is assumed, which is the same
as no limit being taken.