univariate_ilr: Univariate Isometric Log-Ratios (ILR)

In nexus: Sourcing Archaeological Materials by Chemical Composition

Univariate Isometric Log-Ratios (ILR)

Description

Computes univariate ILR coordinates.

Usage

univariate_ilr(object, ...)

## S4 method for signature 'numeric'
univariate_ilr(object)

## S4 method for signature 'matrix'
univariate_ilr(object)

Arguments

object	A CompositionMatrix object.
...	Currently not used.

Details

The ILR transformation provides the coordinates of any composition with respect to a given orthonormal basis. transform_ilr() uses the orthonormal basis (Helmert matrix) originally defined by Egozcue et al. (2003).

Value

Same as object.

Author(s)

N. Frerebeau

References

Filzmoser, P., Hron, K. & Reimann, C. (2009). Univariate Statistical Analysis of Environmental (Compositional) Data: Problems and Possibilities. Science of The Total Environment, 407(23), 6100-6108. \Sexpr[results=rd]{tools:::Rd_expr_doi("10.1016/j.scitotenv.2009.08.008")}.

Filzmoser, P., Hron, K. & Reimann, C. (2010). The Bivariate Statistical Analysis of Environmental (Compositional) Data. Science of The Total Environment, 408(19), 4230-4238. \Sexpr[results=rd]{tools:::Rd_expr_doi("10.1016/j.scitotenv.2010.05.011")}.

Examples

## Data from Aitchison 1986
data("hongite")

## Coerce to compositional data
coda <- as_composition(hongite)

## Isometric log-ratio
ilr <- transform_ilr(coda)
plr <- transform_plr(coda)

## Inverse transformation
inv_ilr <- transform_inverse(ilr)
all.equal(coda, inv_ilr)

inv_plr <- transform_inverse(plr)
all.equal(coda, inv_plr)

nexus documentation built on Sept. 11, 2024, 6:43 p.m.