tring">by</span> <span class="string">hyperparameters</span>                         <span class="string">[ E  x P*E]</span>
dSdX      <span class="string">output</span> <span class="string">covariance</span> <span class="string">by</span> <span class="string">hyperparameters</span>                   <span class="string">[E*E x P*E]</span>
dVdX      <span class="string">inv(s)</span> <span class="string">times</span> <span class="string">input-output</span> <span class="string">covariance</span> <span class