model. To ensure <code>y[1]</code> has a proper
posterior in case it is missing, we have given it an explicit, albeit
broad, prior.</p>
<p>Another potential application would be filling the
columns of a data matrix of predictors for which some predictors are
missing; matrix columns can be accessed as vectors and assigned the
same way, as in</p>
<pre><code>  x[N_obs_2, 2] = x_obs_2;
  x[N_mis_2, 2] = x_mis_2;</code></pre>
<p>where the relevant variables are all hard coded with index <code>2</code> because
St