coordinates: Coordinates of compositions with respect to a basis

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

Coordinates of compositions with respect to a basis

Description

Compute coordinates of a composition or a compositional data set with respect to a given log-ratio basis.

The 'basis' argument can be either:

• a character string identifying a predefined coordinate system, or

• a matrix whose columns define a system of log-contrasts.

The predefined options are:

• '"ilr"': isometric log-ratio coordinates,

• '"olr"': orthonormal log-ratio coordinates,

• '"clr"': centered log-ratio coordinates,

• '"alr"': additive log-ratio coordinates,

• '"pw"': pairwise log-ratios,

• '"pc"': principal component log-ratio coordinates,

• '"pb"': principal balance coordinates,

• '"cdp"': CoDaPack default balances.

Usage

coordinates(X, basis = "ilr")

coord(..., basis = "ilr")

alr_c(X)

clr_c(X)

ilr_c(X)

olr_c(X)

Arguments

X	A compositional data set. It can be a numeric matrix, a data frame, or a numeric vector.
basis	Basis used to compute the coordinates. Either a character string naming a predefined basis or a matrix with log-ratio basis vectors in columns.
...	components of the composition

Value

Coordinates of 'X' with respect to the given 'basis'. The returned object has the same general type as the input when possible.

See Also

ilr_basis, alr_basis, clr_basis, sbp_basis, composition

Examples

coordinates(1:5)

B <- ilr_basis(5)
coordinates(1:5, B)

X <- rbind(1:5, 2:6)
coordinates(X, "clr")

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