% FIGURE 4.6.2
      function DOTA = DTRAN2(Z,J)
      global NWg
      global NSg
%                              DOTA=DOT PRODUCT OF Z AND COLUMN J OF A
      NW = NWg;
      NS = NSg;
      JW = fix((J-1)/NS) + 1;
      JS = mod(J-1,NS) + 1;
      DOTA = Z(JW) + Z(NW+JS);