> is
called with <code>x</code> as the sole argument, and the results are returned.
Similarly, <code><a href="swSigma0.html">swSigma0()</a></code> is used if <code>i="sigma0"</code>, and <code><a href="swSpice.html">swSpice()</a></code> is used if
<code>i="spice"</code>. Of course, these actions only make sense for objects that
contain the relevant items within their <code>data</code> slot.</p></li>
<li><p>After these possibilities are eliminated, the action depends on whether
<code>j</code> has been provid