transform_plr: Pivot Log-Ratios (PLR)

In nexus: Sourcing Archaeological Materials by Chemical Composition

Pivot Log-Ratios (PLR)

Description

Computes PLR transformations.

Usage

transform_plr(object, ...)

## S4 method for signature 'CompositionMatrix'
transform_plr(object, pivot = 1)

Arguments

object	A CompositionMatrix object.
...	Currently not used.
pivot	An integer giving the index of the pivotal variable.

Value

A PLR object.

Author(s)

N. Frerebeau

References

Fišerová, E. & Hron, K. (2011). On the Interpretation of Orthonormal Coordinates for Compositional Data. Mathematical Geosciences, 43(4), 455‑468. \Sexpr[results=rd]{tools:::Rd_expr_doi("10.1007/s11004-011-9333-x")}.

Greenacre, M. J. (2019). Compositional Data Analysis in Practice. Boca Raton: CRC Press.

Greenacre, M. J. (2021). Compositional Data Analysis. Annual Review of Statistics and Its Application, 8(1): 271-299. \Sexpr[results=rd]{tools:::Rd_expr_doi("10.1146/annurev-statistics-042720-124436")}.

Hron, K., Filzmoser, P., de Caritat, P., Fišerová, E. & Gardlo, A. (2017). Weighted Pivot Coordinates for Compositional Data and Their Application to Geochemical Mapping. Mathematical Geosciences, 49(6), 797-814. \Sexpr[results=rd]{tools:::Rd_expr_doi("10.1007/s11004-017-9684-z")}.

See Also

Other log-ratio transformations: transform_alr(), transform_clr(), transform_ilr(), transform_inverse(), transform_lr()

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.