; flipdim(m-2*sqrt(s2),1)]; 
  fill([z; flipdim(z,1)], f, [7 7 7]/8)
  hold on; plot(z, m); plot(x, y, '+')
</pre>

<p>The <tt>gp</tt> function is called with a struct of hyperparameters
<tt>hyp</tt>, and inference method, in this case <a
 href="../inf/infExact.m">@infExact</a> for exact inference and the
mean, covariance and likelihood functions, as well as the inputs and
outputs of the training data. With no test inputs, <tt>gp</tt> returns
the negative log probability of the training data, in this exampl