27     bin_tree.points =  [index(1),index(end)];
0028 <span class="keyword">else</span>
0029     <span class="comment">%% otherwise go on</span>
0030     bin_tree.allow    = 1;    
0031     diff_x = c_x(end) - c_x(1);
0032     diff_y = c_y(end) - c_y(1);
0033     
0034     <span class="comment">%%  line approximation is locus of a x + b y + c =0</span>
0035     <span class="comment">%% a,b,c are calculated from the endpoint locations</span>
0036     <span class="keyword">if</span> diff_y~=0,
0037         b=