rgr: orthonorm – R documentation

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orthonorm

Computation of an Orthonormal Basis Matrix

Description

Computes an othonormal basis matrix to be used for the back-transformation of ilr-based data and statistics to clr-based data and statistics.

Usage

orthonorm(p)

Arguments

`p`	the dimension of the `p`-space, the number of original variables.

Value

`V`	the `p` by `(p-1)` orthormal basis matrix.

Author(s)

Based on a function by Peter Filzmoser and Karel Hron

References

Filzmoser, P., Hron, K., Reimann, C. and Garrett, R., 2009. Robust factor analysis for compositional data. Computers & Geosciences, 35(9):1854-1861.

Examples

## Make test data available
data(sind.mat2open)

## Compute and display clr transformed data
prmatrix(clr(sind.mat2open))

## Compute and display ilr transformed data
sind.ilr <-ilr(sind.mat2open)
prmatrix(sind.ilr)

## Compute and display orthonormal basis matrix
## sind.mat2open is a 25 by 6 matrix (data set)
V <- orthonorm(6)
prmatrix(V)

## Back-transform ilr transformed data to clr form and display
temp <- sind.ilr %*% t(V)
dimnames(temp)[[2]] <- dimnames(sind.mat2open)[[2]]
prmatrix(temp)

## Clean-up
rm(sind.ilr)
rm(V)
rm(temp)

rgr

Applied Geochemistry EDA

v1.1.15

GPL-2

Authors

Robert G. Garrett

Initial release

2018-03-05