make.link {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))

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