asv.asreml {asreml} | R Documentation |
Function to compute the approximate stratum variances, degrees of freedom and coefficients for simple variance component models.
## S3 method for class 'asreml' asv(object, order = c("as.is", "noeff"), vvp = FALSE, ...)
object |
An object of class |
order |
The sequence in which to consider the random terms: may
be one of |
vvp |
If |
... |
Any additional arguments. |
Approximate stratum variances and degrees of freedom for simple
variance components models are returned. For the linear mixed-effects
model, it is often possible to consider a natural ordering of the
variance component parameters, including the residual. Based on an
idea due to Thompson, 1980, asreml
computes approximate
stratum degrees of freedom and stratum variances by a modified
Cholesky diagonalisation of the average information matrix.
If vvp
is FALSE
, a rectangular matrix containing the
degrees of freedom, approximate variances and the component coefficients
for each random term. If vvp
is TRUE
, a list of length two
containing the matrix of approximate stratum variances and the inverse
average information matrix of the variance components in list components
asv
and vvp
, respectively.
Thompson R (1980). “Maximum likelihood estimation of variance components.” Series Statistics, 11(4), 545-561.