R: Loadings of relations of two amounts

ratioLoadings {compositions} | R Documentation

## Loadings of relations of two amounts

### Description

In a compositional dataset the relation of two objects can be interpreted safer than a single amount. These functions compute, display and plot the corresponding pair-information for the various principal component analysis results.

### Usage

    relativeLoadings(x,...)
    ## S3 method for class 'princomp.acomp'
    relativeLoadings(x,...,log=FALSE,scale.sdev=NA,
                                                      cutoff=0.1)
    ## S3 method for class 'princomp.aplus'
    relativeLoadings(x,...,log=FALSE,scale.sdev=NA,
                                                      cutoff=0.1)
    ## S3 method for class 'princomp.rcomp'
    relativeLoadings(x,...,scale.sdev=NA,
                                                      cutoff=0.1)
    ## S3 method for class 'princomp.rplus'
    relativeLoadings(x,...,scale.sdev=NA,
                                                      cutoff=0.1)
    ## S3 method for class 'relativeLoadings.princomp.acomp'
    print(x,...,cutoff=attr(x,"cutoff"),
                                                      digits=2)
    ## S3 method for class 'relativeLoadings.princomp.aplus'
    print(x,...,cutoff=attr(x,"cutoff"),
                                                     digits=2)
    ## S3 method for class 'relativeLoadings.princomp.rcomp'
    print(x,...,cutoff=attr(x,"cutoff"),
                                                     digits=2)
    ## S3 method for class 'relativeLoadings.princomp.rplus'
    print(x,...,cutoff=attr(x,"cutoff"),
                                                     digits=2)
    ## S3 method for class 'relativeLoadings.princomp.acomp'
    plot(x,...)
    ## S3 method for class 'relativeLoadings.princomp.aplus'
    plot(x,...)
    ## S3 method for class 'relativeLoadings.princomp.rcomp'
    plot(x,...)
    ## S3 method for class 'relativeLoadings.princomp.rplus'
    plot(x,...)

### Arguments

`x` | a result from an amount PCA `princomp.acomp`/`princomp.aplus`/`princomp.rcomp`/`princomp.rplus`
`log` | a logical indicating to use log-ratios instead of ratios
`scale.sdev` | if not `NA`, a number specifying the multiple of a standard deviation, used to scale the components
`cutoff` | a single number. Changes under that (log)-cutoff are not displayed
`digits` | the number of digits to be displayed
`...` | further parameters to internally-called functions

### Details

The relative loadings of components allow a direct interpretation of the effects of principal components. For acomp/aplus classes the relation is induced by a ratio, which can optionally be log-transformed. For the rcomp/rplus-classes the relation is induced by a difference, which is meaningless when the units are different.

### Value

The value is a matrix of type `"relativeLoadings.princomp.*"`, containing the ratios in the compositions represented by the loadings (optionally scaled by the standard deviation of the components and `scale.sdev`).

### Author(s)

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

### See Also

`princomp.acomp`, `princomp.aplus`, `princomp.rcomp`, `princomp.rplus`, `barplot`

### Examples

    data(SimulatedAmounts)
    pc <- princomp(acomp(sa.lognormals5))
    pc
    summary(pc)
    relativeLoadings(pc,log=TRUE)
    relativeLoadings(pc)
    relativeLoadings(pc,scale.sdev=1)
    relativeLoadings(pc,scale.sdev=2)

    plot(relativeLoadings(pc,log=TRUE))
    plot(relativeLoadings(pc))
    plot(relativeLoadings(pc,scale.sdev=1))
    plot(relativeLoadings(pc,scale.sdev=2))

[Package compositions version 1.40-2 Index]