TT.chemometrics.alr: Compute the additive log-ratio transformation of compositional data.
Description
Function that compute the additive
log-ratio transformation of compositional data (here texture
data). This a a copy-paste-and-rename of the alr function provided
by the package chemometrics: P. Filzmoser and K. Varmuza (2008).
chemometrics: Multivariate Statistical Analysis in Chemometrics.
R package version 0.4.
The function has been modified so it returns NA when a value
is below or equal to zero (this happens when using a regular
grid of texture data, for practical reasons).
The function has also been modified so it uses column name
rather than column index.Usage
TT.chemometrics.alr(X, divisorvar, css.names)