The additive log-ratio transformation and its inverse {Compositional} | R Documentation |
The additive log-ratio transformation and its inverse.
alr(x) alrinv(y)
x |
A numerical matrix with the compositional data. |
y |
A numerical matrix with data to be closed into the simplex. |
The additive log-ratio transformation with the first component being the common divisor is applied. The inverse of this transformation is also available. This means that no zeros are allowed.
A matrix with the alr transformed data (if alr is used) or with the compositional data (if the alrinv is used).
Michail Tsagris
R implementation and documentation: Michail Tsagris mtsagris@uoc.gr
Aitchison J. (1986). The statistical analysis of compositional data. Chapman & Hall.
bc, pivot, fp, green, alfa, alfainv alfa.profile, alfa.tune
library(MASS) x <- as.matrix(fgl[, 2:9]) x <- x / rowSums(x) y <- alr(x) x1 <- alrinv(y)