acompmargin {compositions} | R Documentation

## Marginal compositions in Aitchison Compositions

### Description

Compute marginal compositions of selected parts, by computing the rest as the geometric mean of the non-selected parts.

### Usage

              acompmargin(X,d=c(1,2),name="*",pos=length(d)+1)

### Arguments

`X` | composition or dataset of compositions
`d` | vector containing the indices xor names of the columns selected
`name` | The new name of the amalgamation column
`pos` | The position where the new amalgamation column should be stored. This defaults to the last column.

### Details

The amalgamation column is simply computed by taking the geometric mean of the non-selected components. This is consistent with the `acomp` approach and gives clear ternary diagrams. However, this geometric mean is difficult to interpret.

### Value

A closed compositions with class `"acomp"` containing the variables given by `d` and the the amalgamation column.

### Missing Policy

MNAR has the highest priority, MAR afterwards, and WZERO (BDL,SZ) values are considered as 0 and finally reported as BDL.

### Author(s)

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

### References

Vera Pawlowsky-Glahn (2003) personal communication. Universitat de Girona. vera.pawlowsky@udg.es

van den Boogaart, K.G. and R. Tolosana-Delgado (2007) "compositions": a unified R package to analyze Compositional Data, Computers & Geosciences. (in press).

### See Also

`rcompmargin`, `acomp`

### Examples

    data(SimulatedAmounts)
    plot.acomp(sa.lognormals5,margin="acomp")
    plot.acomp(acompmargin(sa.lognormals5,c("Pb","Zn")))
    plot.acomp(acompmargin(sa.lognormals5,c(1,2)))

[Package compositions version 0.91-6 Index]