anchor.diff:    a(:,:) = b(lb1, lb2)
     sync all
     if (this_image() == 1) then
  -    caf(:,:)[this_image()] = b(lb1, lb2)
  +    caf(:,:)[num_images()] = b(lb1, lb2)
     end if
     sync all
     if (this_image() == num_images()) then
  
positive.code:   a(:,:) = b(:, :)
    sync all
    if (this_image() == 1) then
      caf(:,:)[this_image()] = b(:, :)
    end if
    sync all
    if (this_image() == num_images()) then
  
negative.code:   a(:,:) = b(:, :)
    sync all
    if (this_image() == 1) then
      caf(:,:)[num_images()] = b(:, :)
    end if
    sync all
    if (this_image() == num_images()) then
  