t>x</tt> exceeds a few 
thousands, exact inference using
<a href="../inf/infExact.m">infExact.m</a> 
takes too long. We offer the FITC approximation based on a low-rank
plus diagonal approximation to the exact covariance to deal with these
cases. The general idea is to use inducing points <tt>u</tt> and to
base the computations on cross-covariances between training, test and
inducing points only.
</p>

<p>
Using the FITC approximation 
is very simple, we just have to wrap the covariance function
<tt>covfunc