d, allows the caller to obtain iteration performance statistics. </td></tr>
    <tr><td class="paramdir">[out]</td><td class="paramname">err</td><td>An optional errors-based object that if provided can be used to retrieve information relating to any errors encountered during execution. If not provided, a default implementation of the errors class is used internally to provide error handling. Possible errors and warning messages that may be encountered are as follows.<ul>
<li>NL_INVALID_OPERATION_ERROR: Occu