contrastModel {randRotation} | R Documentation

## Create transformed model matrix for contrast rotation

### Description

This function takes a model matrix `X` and a contrast matrix `C` and creates a transformed model matrix corresponding to a transformed set of coefficients.

### Usage

    contrastModel(X, C, coef.h = seq_len(ncol(C)))

### Arguments

`X` | `(numeric)` model matrix with dimensions `samples x coefficients`.
`C` | `(numeric)` contrast matrix with dimensions `coefficients x contrasts`. The contrast matrix must have full column rank.
`coef.h` | column numbers of contrasts (in `C`) which should be set as `coef.h` in the transformed model, see `initRandrot`. All columns are set as `coef.h` by default.

### Details

The last n coefficients of the transformed model matrix correspond to the n contrasts. By default, all contrasts are set as `coef.h`. See package vignette for examples of data rotations with contrasts.

### Value

A transformed model matrix with `coef.h` set as attribute.

### Author(s)

Peter Hettegger

### Examples

    group <- c("A", "A", "B", "B")
    X <- model.matrix(~0+group)
    C <- cbind(contrast1 = c(1, -1))
    X2 <- contrastModel(X, C)

[Package randRotation version 1.2.2 Index]