an class="string">times</span> <span class="string">input-output</span> <span class="string">covariance</span> <span class="string">by</span> <span class="string">inputs</span>         <span class="string">[D*E x n*D]</span>
dMdt      <span class="string">output</span> <span class="string">mean</span> <span class="string">by</span> <span class="string">targets</span>                                 <span class="string">[ E  x n*E]</span>
dSdt      <span class="string">output</span> <span class="string">cova