perturbe {compositions} | R Documentation |

## Perturbation of compositions

### Description

The perturbation is the addition operation in the Aitchison geometry of the simplex.

### Usage

```
perturbe(x,y)
## Methods for class "acomp"
## x + y
## x - y
## - x
```

### Arguments

`x` |
compositions of class |

`y` |
compositions of class |

### Details

The perturbation is the basic addition operation of the Aitichson simplex as a vector space. It is defined by:

` (x+y)_i = clo( (x_i y_i)_i )_i `

`perturbe`

and `+`

compute this operation. The only
difference is that `+`

checks the class of its argument, while
`perturbe`

does not check the type of the arguments and can thus
directly be applied to a composition in any form (unclassed, acomp,
rcomp).

The `-`

operation is the inverse of the addition in the usual way
and defined by:

`(x-y)_i:=clo( (x_i/y_i)_i )_i`

and as unary operation respectively as:

`(-x)_i:=clo( (1/y_i)_i )_i`

### Value

An `acomp`

vector or matrix.

### Author(s)

K.Gerald v.d. Boogaart http://www.stat.boogaart.de, Raimon Tolosana-Delgado

### References

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

### See Also

### Examples

```
tmp <- -acomp(1:3)
tmp + acomp(1:3)
```

*compositions*version 2.0-8 Index]