tomatic grid search.</p>
<p>(3) Convergence criteria are very strict as they are based on the
derivatives of the log-likelihood in addition to the parameter stability and
log-likelihood stability.  In some cases, the program may not converge and
reach the maximum number of iterations fixed at 100.  In this case, the user
should check that parameter estimates at the last iteration are not on the
boundaries of the parameter space.  If the parameters are on the boundaries
of the parameter space, the identifiab