;
0315         B(k,j)=B(j,k);
0316     <span class="keyword">end</span>
0317 <span class="keyword">end</span>
0318     
0319 <a name="_sub3" href="#_subfunctions" class="code">function checkindex(IDX,n)</a>
0320 a=zeros(n,1);
0321 <span class="keyword">for</span> k=1:numel(IDX)
0322     <span class="keyword">if</span> any(a(IDX{k})); 
0323         error(<span class="string">'!'</span>);
0324     <span class="keyword">end</span>
0325     a(IDX{k})=1;
0326 <span class="keyword">end</span>
0327     
0328</pre>