alr_basis: Additive log-ratio basis

In coda.base: A Basic Set of Functions for Compositional Data Analysis

Additive log-ratio basis

Description

Construct the transformation matrix associated with additive log-ratio (alr) coordinates.

Usage

alr_basis(dim, denominator = NULL, numerator = NULL)

Arguments

dim	Number of parts. It can be a single integer, a matrix or data frame, or a character vector of part names.
denominator	Part used as denominator. By default, the last part is used.
numerator	Parts used as numerators. By default, all parts except the denominator are used, preserving their original order.

Value

A matrix defining the alr coordinate system.

References

Aitchison, J. (1986). The Statistical Analysis of Compositional Data. Chapman & Hall, London.

Examples

alr_basis(5)
alr_basis(5, 3)
alr_basis(5, 3, c(1, 5, 2, 4))

coda.base documentation built on March 4, 2026, 9:06 a.m.