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