
  hold on; plot(z, m); plot(x, y, '+');
</pre>

<p>Here, we have changed the specification by adding the affine mean
function. All the hyperparameters are learnt by optimizing the
marginal likelihood.</p>

<center><img src="f4.gif" alt="f4.gif"></center><br>

<p>This shows that a much better fit is achieved when allowing a mean
function (although the covariance function is still different from
that of the generating process).</p>

<h4>Large scale regression</h4>

<p>In case the number of training inputs <t