R: Coerce Linear Model to gnm Object

asGnm {gnm} | R Documentation

## Coerce Linear Model to gnm Object

### Description

`asGnm` is a generic function which coerces objects of class "glm" or "lm" to an object of class "gnm".

### Usage

    asGnm(object, ...)

### Arguments

`object` | an object of class "glm" or "lm".
`...` | additional arguments for method functions.

### Details

Components are added to or removed from `object` to produce an object of class "gnm". This can be useful in model building, see examples.

### Value

An object of class "gnm" - see `gnm` for full description.

### Author(s)

Heather Turner

### References

Vargas, M, Crossa, J, van Eeuwijk, F, Sayre, K D and Reynolds, M P (2001). Interpreting treatment by environment interaction in agronomy trials. Agronomy Journal 93, 949–960.

### See Also

`gnm`, `glm`, `lm`

### Examples

    set.seed(1)

    ##  Scale yields to reproduce analyses reported in Vargas et al (2001)
    yield.scaled <- wheat$yield * sqrt(3/1000)
    treatment <- interaction(wheat$tillage, wheat$summerCrop, wheat$manure,
                             wheat$N, sep = "")
    ##  Fit linear model
    mainEffects <- lm(yield.scaled ~ year + treatment, data = wheat)

    ##  Convert to gnm object to allow addition of Mult() term
    svdStart <- residSVD(mainEffects, year, treatment, 3)
    bilinear1 <- update(asGnm(mainEffects), . ~ . +
                        Mult(year, treatment),
                        start = c(coef(mainEffects), svdStart[,1]))

[Package gnm version 1.1-2 Index]