asGnm
is a generic function which coerces objects of class
"glm" or "lm" to an object of class "gnm".
asGnm(object, ...)
An object of class "gnm" - see gnm
for full description.
an object of class "glm" or "lm".
additional arguments for method functions.
Heather Turner
Components are added to or removed from object
to produce an
object of class "gnm". This can be useful in model building,
see examples.
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.
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]))
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