reStruct Model Matrix

model.matrix.reStruct {nlme}

R Documentation

reStruct Model Matrix

Description

The model matrices for each element of formula(object), calculated using data, are bound together column-wise. When multiple grouping levels are present (i.e. when length(object) > 1), the individual model matrices are combined from innermost (at the leftmost position) to outermost (at the rightmost position).

Usage

## S3 method for class 'reStruct'
model.matrix(object, data, contrast, ...)

Arguments

`object`	an object inheriting from class `"reStruct"`, representing a random effects structure and consisting of a list of `pdMat` objects.
`data`	a data frame in which to evaluate the variables defined in `formula(object)`.
`contrast`	an optional named list specifying the contrasts to be used for representing the `factor` variables in `data`. The components names should match the names of the variables in `data` for which the contrasts are to be specified. The components of this list will be used as the `contrasts` attribute of the corresponding factor. If missing, the default contrast specification is used.
`...`	some methods for this generic require additional arguments. None are used in this method.

Value

a matrix obtained by binding together, column-wise, the model matrices for each element of formula(object).

Author(s)

José Pinheiro and Douglas Bates bates@stat.wisc.edu

Examples

rs1 <- reStruct(list(Dog = ~day, Side = ~1), data = Pixel)
model.matrix(rs1, Pixel)

[Package nlme version 3.1-139 Index]