R: Extract Design Matrices

model.matrix.egf {epigrowthfit}

R Documentation

Extract Design Matrices

Description

Extracts from a model object fixed and random effects design matrices.

Usage

## S3 method for class 'egf'
model.matrix(object, which = c("fixed", "random"),
             top = NULL, random = NULL, ...)

Arguments

`object`	an `egf` object.
`which`	a character string controlling what is returned: `"fixed"` the fixed effects design matrix `X` corresponding to `top`. `"random"` the random effects design matrix `Z` corresponding to `top` and `random`.
`top`	a character string specifying a top level nonlinear model parameter. `NULL` indicates “all of them”; see ‘Details’.
`random`	a random effect term, which is a call to binary operator `\|`. `NULL` indicates “all of them”; see ‘Details’.
`...`	unused optional arguments.

Details

model.matrix(which = "fixed", top = NULL) returns the result of combining (in the sense of cbind) all fixed effects design matrices.

model.matrix(which = "random", top = "<name>", random = NULL) returns the result of combining all random effects design matrices associated with parameter top.

model.matrix(which = "random", top = NULL, random = NULL) returns the result of combining all random effects design matrices and permuting the columns to obtain a convenient ordering of random effect coefficients. (Coefficients are sorted by relation to a common random vector. Random vectors are sorted by relation to a common covariance matrix.)

None of these “combined” design matrices possesses attributes assign and contrasts.

Value