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, ...) ## S3 method for class 'rcomp': variation(x, ...) ## S3 method for class 'aplus': variation(x, ...) ## S3 method for class 'rplus': variation(x, ...) ## S3 method for class 'rmult': variation(x, ...)
x |
a dataset, eventually of amounts or compositions |
... |
currently unused |
The variation matrix was defined in the acomp context for 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 and rmult objects should not be treated with variation matrices, because this implies always the existence of a closure.
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) mean.col(sa.lognormals) variation(acomp(sa.lognormals)) variation(rcomp(sa.lognormals)) variation(aplus(sa.lognormals)) variation(rplus(sa.lognormals)) variation(rmult(sa.lognormals))