std_start {mmrm}

Standard Starting Value

Description

Obtain standard start values.

Usage

std_start(cov_type, n_visits, n_groups, ...)

Arguments

cov_type

(string)
name of the covariance structure.

n_visits

(int)
number of visits.

n_groups

(int)
number of groups.

...

not used.

Details

std_start will try to provide variance parameter from identity matrix. However, for ar1 and ar1h the corresponding values are not ideal because the \rho is usually a positive number thus using 0 as starting value can lead to incorrect optimization result, and we use 0.5 as the initial value of \rho.

Value

A numeric vector of starting values.