R: Transform Compositional Data for a Simplex

Simplex-Transformations {DirichletReg} | R Documentation

## Transform Compositional Data for a Simplex

### Description

These functions transform a matrix with three or four components to fit into a two- or three-dimensional simplex (triangle or tetrahedron).

### Usage

    toSimplex(x)

    toTernary(abc)
    toTernaryVectors(c1, c2, c3)

    toQuaternary(abcd)
    toQuaternaryVectors(c1, c2, c3, c4)

### Arguments

`x` | a matrix-like object with 3 or 4 columns.
`abc` | a matrix-like object with 3 columns.
`abcd` | a matrix-like object with 4 columns.
`c1` | a numeric vector with values of the first component.
`c2` | a numeric vector with values of the second component.
`c3` | a numeric vector with values of the third component.
`c4` | a numeric vector with values of the fourth component.

### Details

Most of these functions are only used internally, but sometimes it might be useful to plot “custom” ternary or quaternary graphics.

Note that, apart from `toSimplex()`, functions do not have any checks, so it is advisable to use this function if elements are added to plots or own graphics are created.

### Value

The function returns a `matrix` object with coordinates in two or three dimensions

### Note

In prior versions (up to 0.5-0), an unexported function `coord.trafo()` was used internally and could also be accessed via `DirichletReg:::coord.trafo()`.

If you have used this in your code, you will get a message that the function is now deprecated and will become defunct in the future. Use `toSimplex()` instead.

### Author(s)

Marco J. Maier

### Examples

    # create a DirichletRegData object from the Arctic Lake data
    "to be added"

[Package DirichletReg version 0.7-0 Index]