variation {compositions} | R Documentation |
Compute the variation matrix in the various approaches of compositional and amount data analysis. Pay attention that this is not computing the variance or covariance matrix!
variation(x,...) ## S3 method for class 'acomp': variation(x, ...,robust=getOption("robust")) ## S3 method for class 'rcomp': variation(x, ...,robust=getOption("robust")) ## S3 method for class 'aplus': variation(x, ...,robust=getOption("robust")) ## S3 method for class 'rplus': variation(x, ...,robust=getOption("robust")) ## S3 method for class 'rmult': variation(x, ...,robust=getOption("robust"))
x |
a dataset, eventually of amounts or compositions |
... |
currently unused |
robust |
A description of a robust estimator. FALSE for the classical estimators. See robustnessInCompositions for further details. |
The variation matrix was defined in the acomp
context of
analysis of compositions as the matrix of variances of all
possible log-ratios among components (Aitchison, 1986). The
generalization to rcomp objects is simply to reproduce the
variance of all possible differences between components. The
amount (aplus
, rplus
) and rmult objects
should not be treated with variation
matrices, because this was intended to skip the existence of a closure
(which does not exist in the case of amounts).
The variation matrix of x.
K.Gerald v.d. Boogaart http://www.stat.boogaart.de
cdt
, clrvar2ilr
, clo
,
mean.acomp
, acomp
, rcomp
,
aplus
, rplus
data(SimulatedAmounts) meanCol(sa.lognormals) variation(acomp(sa.lognormals)) variation(rcomp(sa.lognormals)) variation(aplus(sa.lognormals)) variation(rplus(sa.lognormals)) variation(rmult(sa.lognormals))