em.control(maxit = 100, tol = 1e-08, crit = "relative", random.start = TRUE)em.control returns a list of the control parameters.crit sets the convergence criterion to either the
relative change in the log-likelihood or the absolute change in the
log-likelihood. The relative likelihood criterion (the default) assumes
convergence on iteration $i$ when $\frac{\log L(i) - \log
L(i-1)}{\log L(i-1)} < tol$. The absolute likelihood criterion assumes convergence on iteration
$i$ when $\log L(i) - \log L(i-1) < tol$. Use crit="absolute" to invoke the latter
convergence criterion. Note that in that case, optimal values of the
tolerance parameter tol scale with the value of the log-likelihood. Argument random.start This is used for a (limited) random
initialization of the parameters. In particular, if
random.start=TRUE, the (posterior) state probabilities are
randomized at iteration 0 (using a uniform distribution). Random
initialization is useful when no initial parameters can be given to
distinguish between the states. It is also useful for repeated estimation
from different starting values.