clr: Centered log ratio transformation
In Hotelling: Hotelling's T^2 Test and Variants

Description Usage Arguments Details Value Author(s) References See Also Examples

View source: R/clr.R

Aitchison's centered log ratio tranformation for compositional data

1	clr(data, group = NULL)

`data`	a data frame in which the data is stored
`group`	if not NULL then a character string specifying the name of the grouping variable

This function will give a warning if zeros are present because the transformed data will have -Infs.

a data frame with the CLR transformation applied to data. Each row in the data frame is standardized by dividing by the geometric mean of that row. The logarithms of the resulting ratios are returned. If a grouping variable is specified, then this is preserved.

James M. Curran

Aitchison, J. (1986). “The Statistical Analysis of Compositional Data”, Chapman and Hall, reprinted in 2003 with additional material by The Blackburn Press

alr

data(bottle.df)

## transform preserving grouping
clr(bottle.df, "Number")

## transform the data but remove the
## grouping in column 1
clr(bottle.df[,-1])