 class="comment">%* safeguards                                *</span>
0375       <span class="comment">%*********************************************</span>
0376       
0377       <span class="keyword">if</span> (alp1 == 0)
0378         error(<span class="string">'programming error in extrapolation step of line search (alp1==0)'</span>);
0379       <span class="keyword">elseif</span> (alp2 == 0)
0380         <span class="comment">% only long steps mu&lt;1/2</span>
0381         <span class="keyword">if</spa