anchor.diff:            popcnt(xor( key1(2,2,i), key2(2,2)))
         if (degree_x2 > 4) then
           cycle
  -      else if(degree_x2 .ne. 0)then
  +      else if(degree_x2 /= 0)then
           idx(l) = i
           l = l+1
         endif
  
positive.code:           popcnt(xor( key1(3,2,i), key2(3,2)))
        if (degree_x2 > 4) then
          cycle
        else if(degree_x2 .ne. 0)then
          idx(l) = i
          l = l+1
        endif
  
negative.code:           popcnt(xor( key1(1,2,i), key2(1,2)))
        if (degree_x2 > 4) then
          cycle
        else if(degree_x2 /= 0)then
          idx(l) = i
          l = l+1
        endif
  