box {flowClust} | R Documentation

## Box-Cox Transformation

### Description

This function performs Box-Cox transformation on the inputted data matrix.

### Usage

    box(data, lambda)

### Arguments

`data` | A numeric vector, matrix or data frame of observations. Negative data values are permitted.
`lambda` | The transformation to be applied to the data. If negative data values are present, `lambda` has to be positive.

### Details

To allow for negative data values, a slightly modified version of the original Box-Cox (1964) is used here. This modified version originated from Bickel and Doksum (1981), taking the following form:

f(y) = ( sgn(y) abs(y)^(lambda) -1 ) / lambda

When negative data values are involved, the transformation parameter, \code{lambda}, has to be positive in order to avoid discontinuity across zero.

### Value

A numeric vector, matrix or data frame of the same dimension as `data` is returned.

### References

Bickel, P. J. and Doksum, K. A. (1981) An Analysis of Transformations Revisited. J. Amer. Statist. Assoc. 76(374), 296-311.

Box, G. E. P. and Cox, D. R. (1964) An Analysis of Transformations. J. R. Statist. Soc. B 26, 211-252.

### See Also

`rbox`

### Examples

    data(rituximab)
    library(flowCore)
    data <- exprs(rituximab)
    summary(data)
    # Transform data using Box-Cox with lambda=0.3
    dataTrans <- box(data, 0.3)
    # Reverse transform data; this should return back to the original rituximab data
    summary(rbox(dataTrans, 0.3))

[Package flowClust version 3.18.0 Index]