create.Tau2: Create a variance component of the heterogeneity of the random effects
Description
It creates variance component of the heterogeneity of the
random effects by decomposing the variance component into matrices of
correlation and standard deviations.
The RAM model for testing. no.var is calculated from it.
no.var
If RAM is missing, the user has to specify
the no.var argument. It represents the no.var by no.var of the random effects).
Tau1.labels
Parameter labels in Tau1. The default is
Tau1_1, Tau1_2, etc.
RE.type
Either "Diag", "Symm", "Zero" or "User". If
it is"Diag" (the default if missing), a diagonal matrix is used
for the random effects meaning that the random effects are
independent. If it is "Symm", a symmetric matrix is used for the random effects on the covariances
among the correlation (or covariance) vectors. If it is
"Zero", a zero matrix is assumed on the variance component of
the random effects. If it is "User", users have to specify the
RE.true argument.
RE.User
It represents the no.var by no.var symmetric matrix
of TRUE or FALSE for the variance component. If the
elements are FALSE, they are fixed at 0.
Transform
Either "expLog" or "sqSD". If it is
"expLog", the variances are estimated by applying a log and exp
transformation. If it is "sqSD", the variances are estimated by
applying a square on the SD. The transformation may improve the
estimation when the heterogeneity is small or close to zero.
RE.startvalues
Starting values for the variances.
Value
A list of MxMatrix-class. The variance component is
computed in Tau2.