function [Node] = sgnt_vhp_1(node)
  [nr,nc]= size(node);
 m = nc - 4;
 
 for i=2:1:nr                       % -------------------------- 1 end
    
    if node(i,m+2) > 0 & node(node(i,m+2),m+2) > 0    % -------- 2 end
        parent_pt= node(i,m+2);
        grandparent_pt= node(parent_pt,m+2);
        
        wn = node(i,1:m);
        wp = node(parent_pt,1:m);
        wg = node(grandparent_pt,1:m); 
       
        dnp=sum((wn - wp).^2);
        dng=sum((wn - wg).^2);
        
        if dnp > dng                          % --------------------------- 3 end
             % update np 
             temp = node(parent_pt,m+1);
             node(parent_pt,m+1)= node(parent_pt,m+1)- node(i,m+1);
             if node(parent_pt,m+1) <= 0    node(parent_pt,m+1) = 1;       end
             
             node(parent_pt,1:m)= (node(parent_pt,1:m).*temp - node(i,1:m)*node(i,m+1))/node(parent_pt,m+1);
                        
             % connect(n,ng)
                         
             if node(parent_pt,m+3) == i             % node i is a first sibling (the most left sibling)
                 node(parent_pt,m+3) = node(i,m+4);
             else                                   % node i isn't a first sibling 
                 jj =  node(parent_pt,m+3);            
                 while (jj > 0 & node(jj,m+4)~=i )
                     jj = node(jj,m+4);
                 end
                 
                if jj > 0   
                    node(jj,m+4)= node(i,m+4);                    
                end                
            end
             node(i,m+2) = grandparent_pt;   %  1
             node(i,m+4) = node(grandparent_pt, m+3);
             node(grandparent_pt, m+3) = i;
             
        end                            % --------------------------- 3 end
     end                                                  % -------- 2 end
 end                                    % -------------------------- 1 end
 Node = node;