stoch, <span class="string">'-'</span>, <span class="keyword">...</span>
     parvals, errvals_wc, <span class="string">'-'</span>, [-1;-1], [0; 12], <span class="string">'k--'</span>, <span class="keyword">...</span>
     [1;1], [0; 12], <span class="string">'k--'</span>);
xlabel(<span class="string">'u'</span>);
ylabel(<span class="string">'r(u) = ||A(u)x-b||_2'</span>);
title(<span class="string">'Residual r(u) vs a parameter u for three approximate solutions'</span>);
<span class="comment">% print -deps