CompositionalClust (version 1.2)

The alpha-transformation: The \(\alpha\)-transformation

Description

The \(\alpha\)-transformation.

Usage

alfa(x, a)

Value

The \(\alpha\)-transformed data.

Arguments

x

A matrix with the compositional data.

a

The value of the power transformation, it has to be between -1 and 1. If zero values are present it has to be greater than 0. If \(\alpha=0\) the isometric log-ratio transformation is applied.

Author

Michail Tsagris.

R implementation and documentation: Michail Tsagris .

Details

The \(\alpha\)-transformation is applied to the compositional data.

References

Tsagris M.T., Preston S. and Wood A.T.A. (2011). A data-based power transformation for compositional data. In Proceedings of the 4th Compositional Data Analysis Workshop, Girona, Spain. https://arxiv.org/pdf/1106.1451.pdf

See Also

alfa.kmeans

Examples

y <- as.matrix(iris[, 1:4])
y <- y / rowSums(y)
ya <- alfa(y, 0.2)