anchor.diff:    SUBROUTINE Add_qutree_pls_qutree(qA,qB,qC)
       IMPLICIT NONE
       TYPE(QuTree), POINTER       :: qA,qB,qC
  +    REAL(DOUBLE) :: norm
       INTEGER :: add_quadcount
  -
       IF(.NOT.ASSOCIATED(qC))THEN
          CALL NewQuNode(qC,init=.TRUE.)
       ELSE
  
positive.code:   SUBROUTINE DeleteQuad(qA)
      TYPE(QuTree),POINTER :: qA
      CALL SpAMM_DeleteQuad(qA)
  !    DEALLOCATE(qA)
  !    NULLIFY(qA)
    END SUBROUTINE DeleteQuad
  
    RECURSIVE SUBROUTINE SpAMM_DeleteQuad(qA)
  
negative.code:   READ(BUFFER,*)Nel
    CALL GETARG(4,BUFFER)
    READ(BUFFER,*)SpAMM_tolerance
    !--------------------------------------------------
    K=CEILING(LOG10(DBLE(N))/LOG10(2D0))
    N_OLD=N
    N=2**K
    SpAMM_dimension=N
    SpAMM_tiles=CEILING(DBLE(N)/SpAMM_BLOCK_SIZE)
    SpAMM_levels=CEILING(LOG(DBLE(SpAMM_tiles))/LOG(2D0))+1
    ! ~ ~
    ALLOCATE(A_NOPADDING(1:N_OLD,1:N_OLD))
    !--------------------------------------------------
    OPEN(UNIT=66,FILE=TRIM(NAME)//".f_ortho")
  