Calculate root variance inflation factors (RVIF) for terms in a
fitted model(s), i.e. the square root of the (generalised) VIFs.

## Arguments

- ...
Arguments to `VIF()`

.

## Value

A numeric vector of the RVIFs, or an array, list of vectors/arrays,
or nested list.

## Details

RVIFs quantify the inflation of estimate standard errors due to
multicollinearity among predictors, and also of estimates themselves
compared to the 'unique' (residualised) effects. RVIFs may often be more
practical than VIFs for assessing multicollinearity, relating more directly
to the parameters of interest.