a list containing one or more matrix or bdsmatrix objects.
rescale
if TRUE, each input matrix is rescaled to have a diagonal of 1.
(Kinship matrices for instance are often generated with a diagonal
of .5 and would be multiplied by 2).
pdcheck
check each matrix to ensure that it is positive definite
positive
constrain coefficients to be positive. This may also be a vector of
the same length as varlist
Value
a coxme variance family object, used by coxme in the fitting process.
Details
If two matrices $A$ and $B$ were given, this fits
the variance structure
$V= \sigma_1^2 A + \sigma_2^2 B$,
where the variances $\sigma_1^2$ and $\sigma_2^2$ are
parameters that will be optimized by coxme,
treating $A$ and $B$ as fixed.