Greenacre's power transformation {Compositional} | R Documentation |
Greenacre's power transformation.
green(x, theta)
x |
A matrix with the compositional data. |
theta |
The value of the power transformation, it has to be between -1 and 1. If zero values are present it has to be greater than 0. If θ=0 the log transformation is applied. |
Greenacre's transformation is applied to the compositional data.
A matrix with the power transformed data.
Michail Tsagris
R implementation and documentation: Michail Tsagris mtsagris@uoc.gr.
Greenacre, M. (2009). Power transformations in correspondence analysis. Computational Statistics & Data Analysis, 53(8): 3107-3116. http://www.econ.upf.edu/~michael/work/PowerCA.pdf
library(MASS) x <- as.matrix(fgl[, 2:9]) x <- x / rowSums(x) y1 <- green(x, 0.1) y2 <- green(x, 0.2) rbind( colMeans(y1), colMeans(y2) )