Computes ILR transformations.
Usage
transform_ilr(object, ...)
# S4 method for class 'CompositionMatrix'
transform_ilr(object)
# S4 method for class 'GroupedComposition'
transform_ilr(object)
# S4 method for class 'CLR'
transform_ilr(object)
# S4 method for class 'GroupedCLR'
transform_ilr(object)
# S4 method for class 'ALR'
transform_ilr(object)
# S4 method for class 'GroupedALR'
transform_ilr(object)Arguments
- object
A
CompositionMatrixobject.- ...
Currently not used.
Value
An ILR object.
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).
References
Egozcue, J. J., Pawlowsky-Glahn, V., Mateu-Figueras, G. & Barceló-Vidal, C. (2003). Isometric Logratio Transformations for Compositional Data Analysis. Mathematical Geology, 35(3), 279-300. doi:10.1023/A:1023818214614 .
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. doi:10.1146/annurev-statistics-042720-124436 .
See also
Other log-ratio transformations:
transform_alr(),
transform_clr(),
transform_inverse(),
transform_lr(),
transform_plr()
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)
#> [1] TRUE
inv_plr <- transform_inverse(plr)
all.equal(coda, inv_plr)
#> [1] TRUE