make.link               package:stats               R Documentation

Create a Link for GLM families

Description:

     This function is used with the 'family' functions in 'glm()'.
     Given a link, it returns a link function, an inverse link
     function, the derivative dmu/deta and a function for domain
     checking.

Usage:

     make.link(link)

Arguments:

    link: character or numeric; one of '"logit"', '"probit"',
          '"cloglog"', '"identity"', '"log"',  '"sqrt"',  '"1/mu^2"',
          '"inverse"', or number, say lambda resulting in power link mu
          ^ lambda.

Value:

     A list with components 

 linkfun: Link function 'function(mu)'

 linkinv: Inverse link function 'function(eta)'

  mu.eta: Derivative 'function(eta)' dmu/deta

valideta: 'function(eta)'{ 'TRUE' if all of 'eta' is in the domain of
          'linkinv' }.

See Also:

     'glm', 'family'.

Examples:

     str(make.link("logit"))

     l2 <- make.link(2)
     l2$linkfun(0:3)# 0 1 4 9
     l2$mu.eta(eta= 1:2)#= 1/(2*sqrt(eta))

