compositions (version 2.0-2)

gsigetBalStruct: An auxiliary functions to compute user-defined ilr and ipt transforms.

Description

Parses the expressions for the balance functions.

Usage

gsi.getBalStruct(descr,names,allowMinus=FALSE,allowOne=FALSE)

Arguments

descr

the expression

names

character: the variables in the dataset

allowMinus

whether to allow for - as a synonym for /

allowOne

whether to allow 1 as a variable name playing the role of a a constant.

Value

provides a list of pairs giving the components in the Numerator and the Denominator of the balances.

Details

These functions will not be usually called on themselves, but through their wrappers, mainly balanceBase.

References

Egozcue J.J., V. Pawlowsky-Glahn, G. Mateu-Figueras and C. Barcel'o-Vidal (2003) Isometric logratio transformations for compositional data analysis. Mathematical Geology, 35(3) 279-300

See Also

ilrBase,ipt,ilr, http://ima.udg.es/Activitats/CoDaWork03/

Examples

# NOT RUN {
#gsi.getBalStruct(~A/B/C,c("A","B","C"))

# }