gx.symm.coords.mat: Create a Matrix of Symmetric Coordinates

In rgr: Applied Geochemistry EDA

Description

Function to compute a matrix of symmetric coordinates for any two parts, v1 and v2, of a n by p data frame or matrix of compositions.

Usage

gx.symm.coords.mat(x, v1, v2)

Arguments

x	a data frame or matrix of compositions.
v1	the index of the first part for which symmetric coordinates are required.
v2	the index of the second part for which symmetric coordinates are required.

Value

z	a n by 2 matrix containing the symmetric coordinates of parts v1 and v2. The column names are the names of the parts in the input data frame or matrix x.

Note

Any less than detection limit values represented by negative values, or zeros or other numeric codes representing blanks in the data, must be removed prior to executing this function, see ltdl.fix.df.

For compositional data analysis all the data must be in the same measurement units.

Author(s)

Robert G. Garrett

References

Kynclova, P., Hron, K., and Filzmoser, P., 2017. Correlation Between Compositional Parts Based on Symmetric Balances. Mathematical Geosciences, 49:777-796.

See Also

gx.symm.coords

Examples

## Make test data available
data(nockolds)

## Compute and display symmetric coordinates for Ca and Na
gx.symm.coords.mat(nockolds, 6, 7)

## Detach test data
rm(nockolds)

Example output

Loading required package: MASS
Loading required package: fastICA
  ** Are the data/parts all in the same measurement units? **
              Ca          Na
 [1,] -0.2577968  1.36367492
 [2,]  0.1160958  0.99319806
 [3,]  0.5437502  0.89397413
 [4,]  0.8294690  0.94253243
 [5,]  1.0841879  0.94564880
 [6,]  0.4092016  1.21183792
 [7,]  0.7136419  0.71590217
 [8,]  1.0521978  0.43414250
 [9,]  1.0830857  0.50037570
[10,]  1.2313808  0.35244163
[11,]  1.6314732  0.07995084
[12,]  0.8027899 -0.98094555
[13,]  2.1803971  1.49291991
[14,]  0.1011000  1.63464163
[15,]  1.1900499  0.60444074
[16,]  1.3887250  1.25076028

rgr documentation built on May 2, 2019, 6:09 a.m.