Computes ILR transformations.
Arguments
- object
A CompositionMatrix object.
- ...
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.
See also
Other log-ratio transformations:
transform_alr()
,
transform_clr()
,
transform_inverse()
,
transform_lr()
,
transform_plr()
Examples
## Coerce to compositional data
data("hongite")
coda <- as_composition(hongite)
## Pairwise log-ratio
lr <- transform_lr(coda)
## Centered log-ratio
clr <- transform_clr(coda)
## Additive log-ratio
alr <- transform_alr(coda)
## Isometric log-ratio
ilr <- transform_ilr(coda)
plr <- transform_plr(coda)
## Inverse transformation
inv_clr <- transform_inverse(clr)
all.equal(coda, inv_clr)
#> [1] TRUE
inv_alr <- transform_inverse(alr)
all.equal(coda, inv_alr)
#> [1] TRUE
inv_ilr <- transform_inverse(ilr)
all.equal(coda, inv_ilr)
#> [1] TRUE
inv_plr <- transform_inverse(plr)
all.equal(coda, inv_plr)
#> [1] TRUE