compositions (version 0.9-11)

idt: Isometric default transform

Description

Compute the isometric default transform of a vector (or dataset) of compositions or amounts in the selected class.

Usage

idt(x)
          ## S3 method for class 'default':
idt( x )
          ## S3 method for class 'acomp':
idt( x )
          ## S3 method for class 'rcomp':
idt( x )
          ## S3 method for class 'aplus':
idt( x )
          ## S3 method for class 'rplus':
idt( x )
          ## S3 method for class 'rmult':
idt( x )
          ## S3 method for class 'factor':
idt( x )

Arguments

x

a classed amount or composition, to be transformed with its isometric default transform

Value

• A corresponding matrix of row-vectors containing the transforms.

Details

The general idea of this package is to analyse the same data with different geometric concepts, in a fashion as similar as possible. For each of the four concepts there exists an isometric transform expressing the geometry in a full-rank euclidean vector space. Such a transformation is computed by idt. For acomp the transform is ilr, for rcomp it is ipt, for aplus it is ilt, and for rplus it is iit. Keep in mind that the transform does not keep the variable names, since there is no guaranteed one-to-one relation between the original parts and each transformed variable.

See Also

cdt, ilr, ipt, ilt, iit

Examples

# the idt is defined by
idt         <- function(x) UseMethod("idt",x)
idt.default <- function(x) x
idt.acomp   <- function(x) ilr(x) 
idt.rcomp   <- function(x) ipt(x) 
idt.aplus   <- ilt 
idt.rplus   <- iit
idt(acomp(1:5))
idt(rcomp(1:5))