engine(bnet, 'exact');
</pre>
For pedagogical purposes, an implementation of BK-FF that uses an HMM
instead of junction tree is available at
<tt>bk_ff_hmm_inf_engine</tt>.



<h2><a name="cts">Continuous hidden nodes</h2>

If all the hidden nodes are linear-Gaussian, <em>and</em> the observed nodes are
linear-Gaussian,
the model is a <a href="http://www.cs.berkeley.edu/~murphyk/Bayes/kalman.html">
linear dynamical system</a> (LDS).
A DBN can be converted to an LDS if all the hidden nodes are linear-Gaussian