ModelMatrix: Model Matrix
In sasLM: 'SAS' Linear Model

ModelMatrix

R Documentation

Model Matrix

This model matrix is similar to model.matrix. But it does not omit unnecessary columns.

  ModelMatrix(Formula, Data, KeepOrder=FALSE, XpX=FALSE)

`Formula`	a conventional formula for a linear model
`Data`	a `data.frame` to be analyzed
`KeepOrder`	If `KeepOrder` is `TRUE`, terms in `Formula` will be kept. This is for Type I SS.
`XpX`	If `XpX` is `TRUE`, the cross-product of the design matrix (XpX, X'X) will be returned instead of the design matrix (X).

It makes the model(design) matrix for GLM.

Model matrix and attributes similar to the output of model.matrix.

`X`	design matrix, i.e. model matrix
`XpX`	cross-product of the design matrix, X'X
`terms`	detailed information about terms such as formula and labels
`termsIndices`	term indices
`assign`	assignemnt of columns for each term in order, different way of expressing term indices