Function computes the Robust ilr Stability for two parts of a composition following the procedure in Filzmoser et al. (2010), see details below.
ilr.stab(xx1, xx2, ifwarn = T)
a column vector from a matrix or data frame of compositional data,
another column vector from the matrix or data frame of compositional data,
The ilr transform of two parts of a composition is
ilr.xy = 1/(sqrt(2)) * log(x1/x2). The Robust ilr Stability (Filzmoser et al., 2010) is computed from the MAD of the
ilr.xy values. This is normalized into the
(0,1) interval as
exp(-ilr.MAD * ilr.MAD), following the procedure of Buccianti and Pawlowsky-Glahn (2005).
Any less than detection limit values represented by negative values, or zeros or other numeric codes representing blanks in the data, must be removed prior to executing this function, see
Any data vectors (rows) containing
NAs are removed prior to computation.
Robert G. Garrett
Buccianti, a. and Pawlowsky-Glahn, V., 2005. New perspectives on water chemistry and compositional data analysis. Mathematical Geology, 37(7):703-727.
Filzmoser, P, Hron, K. and Reimann, C., 2010. The bivariate statistical analysis of environmental (compositional) data. Science of the Total Environment, 408(19):4230-4238.
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