Inverse additive logratio mapping
Inverse additive logratio mapping, often called additive logistic transformation.
addLRinv(x, cnames = NULL, ivar = NULL, useClassInfo = TRUE)
x |
data set, object of class “alr”, “matrix” or “data.frame” |
cnames |
column names. If the object is of class “alr” the column names are chosen from therein. |
ivar |
index of the rationing part. If the object is of class “alr” the column names are chosen from therein. If not and ivar is not provided by the user, it is assumed that the rationing part was the last column of the data in the simplex. |
useClassInfo |
if FALSE, the class information of object |
The function allows also to preserve absolute values when class info is provided. Otherwise only the relative information is preserved.
the resulting compositional data matrix
Matthias Templ
Aitchison, J. (1986) The Statistical Analysis of Compositional Data Monographs on Statistics and Applied Probability. Chapman \& Hall Ltd., London (UK). 416p.
data(arcticLake) x <- arcticLake x.alr <- addLR(x, 2) y <- addLRinv(x.alr) ## This exactly fulfills: addLRinv(addLR(x, 3)) data(expenditures) x <- expenditures y <- addLRinv(addLR(x, 5, 2)) head(x) head(y) ## --> absolute values are preserved as well. ## preserve only the ratios: addLRinv(x.alr, ivar=2, useClassInfo=FALSE)
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