lass="keyword">if</span> (strcmp(varargin{na},<span class="string">'deriv'</span>)) <span class="comment">% numeric row vector, up to deg elements.</span>
0402         deriv = varargin{na+1};
0403         inc = 2;
0404     <span class="keyword">end</span>;
0405     <span class="keyword">if</span> (strcmp(varargin{na},<span class="string">'renorm'</span>)) <span class="comment">% density renormalization.</span>
0406         deren = varargin{na+1};
0407         inc = 2;
0408     <span class="keyword">e