R: Specify Multiple Instances of a Nonlinear Term in a gnm Model...

instances {gnm} | R Documentation

## Specify Multiple Instances of a Nonlinear Term in a gnm Model Formula

### Description

A symbolic wrapper, for use in the formula argument to `gnm`, to specify multiple instances of a term specified by a function with an `inst` argument.

### Usage

    instances(term, instances = 1)

### Arguments

`term` | a call to a function with an inst argument, which specifies some term.
`instances` | the desired number of instances of the term.

### Value

A deparsed expression representing the summation of `term` specified with `inst = 1`, `inst = 2`, ..., `inst = instances`, which is used to create an expanded formula.

### Author(s)

Heather Turner

### See Also

`gnm`, `formula`, `nonlin.function`, `Mult`, `MultHomog`

### Examples

    ## Not run:
    ## (this example can take quite a while to run)
    ##
    ## Fitting two instances of a multiplicative interaction (i.e. a
    ## two-component interaction)
    yield.scaled <- wheat$yield * sqrt(3/1000)
    treatment <- factor(paste(wheat$tillage, wheat$summerCrop, wheat$manure,
                              wheat$N, sep = ""))
    bilinear2 <- gnm(yield.scaled ~ year + treatment +
                     instances(Mult(year, treatment), 2),
                     family = gaussian, data = wheat)

    ## End(Not run)

[Package gnm version 1.1-2 Index]