R: Centred log-ratio transformation

cenLR {robCompositions} | R Documentation

## Centred log-ratio transformation

### Description

The cenLR transformation moves D-part compositional data from the simplex into a D-dimensional real space.

### Usage

    cenLR(x, base = exp(1))

### Arguments

`x` | multivariate data ideally of class data.frame or matrix
`base` | a positive or complex number: the base with respect to which logarithms are computed. Defaults to `exp(1)`.

### Details

Each composition is divided by the geometric mean of its parts before the logarithm is taken.

### Value

The transformed data, including

`x.clr` | clr transformed data
`gm` | the geometric means of the original composition.

### Note

The resulting transformed data set is singular by definition.

### Author(s)

Matthias Templ

### References

Aitchison, J. (1986) The Statistical Analysis of Compositional Data Monographs on Statistics and Applied Probability. Chapman \& Hall Ltd., London (UK). 416p.

### See Also

`cenLRinv`, `addLR`, `pivotCoord`, `addLRinv`, `pivotCoordInv`

### Examples

    data(expenditures)
    eclr <- cenLR(expenditures)
    inveclr <- cenLRinv(eclr)
    head(expenditures)
    head(inveclr)
    head(pivotCoordInv(eclr$x.clr))

[Package robCompositions version 2.0.6 Index]