Obtain empirical start value for unstructured covariance
Usage
emp_start(
y_vector,
x_matrix,
full_frame,
visit_var,
subject_var,
subject_groups,
...
)
Arguments
- y_vector
(numeric) response variable.
- x_matrix
(matrix) design matrix.
- full_frame
(data.frame) full data frame used for model fitting.
- visit_var
(string)
visit variable.
- subject_var
(string)
subject id variable.
- subject_groups
(factor)
subject group assignment.
- ...
not used.
Value
A numeric vector of starting values.
Details
This emp_start only works for unstructured covariance structure.
It uses linear regression to first obtain the coefficients and use the residuals
to obtain the empirical variance-covariance, and it is then used to obtain the
starting values.
