getV: Determine V-Matrix for a 'VCA' Object.
Description
Determine the estimated variance-covariance matrix of
observations $y$.Value
- (VCA) object with additional elements in the 'Matrices'
element, including matrix $V$.
Details
A linear mixed model can be written as $y = Xb + Zg +
e$, where $y$ is the column vector of observations,
$X$ and $Z$ are design matrices assigning fixed
($b$), respectively, random ($g$) effects to
observations, and $e$ is the column vector of residual
errors. The variance-covariance matrix of $y$ is equal
to $Var(y) = ZGZ^{-T} + R$, where
$R$ is the variance-covariance matrix of $e$.