ape(yfit,length(x1),length(x2));
0091   <span class="keyword">if</span> (type==<span class="string">'c'</span>)
0092     [C h] = contour(x1,x2,yfit',plotargs{:});
0093     clabel(C,h);
0094     <span class="keyword">if</span> (showdata)
0095       hold on;
0096       <a href="plotbyfactor.html" class="code" title="function plotbyfactor(x,y,f)">plotbyfactor</a>(xdata(:,1),xdata(:,2),cdata);
0097       hold off;
0098     <span class="keyword">end</span>;
0099   <span class="keyword">else</span>
0100