alr_basis {coda.base} | R Documentation |

## Additive log-ratio basis

### Description

Compute the transformation matrix to express a composition using the oblique additive log-ratio coordinates.

### Usage

```
alr_basis(dim, denominator = dim, numerator = which(denominator != 1:dim))
```

### Arguments

`dim` |
number of parts |

`denominator` |
part used as denominator (default behaviour is to use last part) |

`numerator` |
parts to be used as numerator. By default all except the denominator parts are chosen following original order. |

### Value

matrix

### References

Aitchison, J. (1986)
*The Statistical Analysis of Compositional Data*.
Monographs on Statistics and Applied Probability. Chapman & Hall Ltd., London (UK). 416p.

### Examples

```
alr_basis(5)
# Third part is used as denominator
alr_basis(5, 3)
# Third part is used as denominator, and
# other parts are rearranged
alr_basis(5, 3, c(1,5,2,4))
```

[Package

*coda.base*version 0.5.5 Index]