R: vgram2lrvgram

lrvgram {compositions} | R Documentation

## vgram2lrvgram

### Description

Transforms model functions for different types of compositional (logratio)(co)variograms.

### Usage

    cgram2vgram(cgram)
    vgram2lrvgram(vgram)

### Arguments

`cgram` | A (matrix valued) covariance function.
`vgram` | A (matrix valued) variogram functions.

### Details

The variogram is given by `cgram(0)-cgram(h)` and `lrvgram(h)[,i,j]==vgram(h)[,i,i]+vgram(h)[,i,j]-2*vgram(h)[,i,j]`.

The logratio-variogram is the set of variograms of each of the pairwise logratios. It can be proven that it carries the same information as a usual multivariate variogram. The great advantage is that all the funcitions have a direct interpreation and can be estimated even with (MAR) missings in the dataset.

### Value

A function that takes the same parameters as the input function (through a ... parameterlist), but provides the correponding variogram values (cgram2vgram) or logratio Variogram (vgram2lrvgram) values.

### Author(s)

K.Gerald v.d. Boogaart http://www.stat.boogaart.de

### References

Tolosana, van den Boogaart, Pawlowsky-Glahn (2009) Estimating and modeling variograms of compositional data with occasional missing variables in R, StatGis09

### See Also

`logratioVariogram`, `CompLinModCoReg`, `vgmFit`

### Examples

    data(juraset)
    comp <- acomp(juraset,c("Cd","Cu","Pb","Co","Cr"))
    vg <- CompLinModCoReg(~nugget()+sph(0.5)+R1*exp(0.7),comp)
    vg(1:3)
    vgram2lrvgram(vg)(1:3)

[Package compositions version 2.0-4 Index]