Calculates and displays the probability that a given observation sample was
generated by the current model parameters.
Usage: likelihood( object1 )
where object is the MTK object containing the observation sample.
Output: Prints both the likelihood and the log-likelihood of the
observation sample in object.
Optimized Likelihood Calculation: As the training method, the
likelihood method has an optimized version, which works, basically in
the same way as training_fast.
Usage: likelihood_fast( object1 )